Suggestion Scheme System

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SUGGESTION SCHEME

SYSTEM

INTRODUCTION

SUGGESTION SCHEME SYSTEM is all about giving your suggestions and sharing yournew innovative ideas to make your department work better.In this project user can give his suggestion related to any department , which he

thinks can make his department work better.He can also give up to five links related to his suggestion and also upload a file or some

text.The next section is share a new idea or concept in which you can share your idea orconcept which you have seen is implemented in some other organization or you have

read about it in some article and you think that concept to b implemented in your

department also.Here also you can give five links and upload one file. Next section can only be controlled by the head of department (HOD), he can show

those ideas or concepts that were suggested or shared by some user and now they are

implemented by the department.He can also change his password. Next section enables you to view all the suggestions, ideas or concept and those

suggestions which are implemented by the department. Here you can view department wise by selecting the department for which you want to

view.You can also view date wise i.e. between a certain intervals of time (for e.g.

07/01/2006-08/02/2006).The next section is for the administrator, he had to give his username and password for

accessing this section, he can change his id or password and he can only delete any

suggestion, idea, concept or implemented share idea if there is a need to do so. Finally the last section is for the user help, if he finds any problem in using this system

he can click on the help and try and solve his problem.

TOOLS AND PLATFORM USEDIn this project the language used is jsp (java server pages) and HTML and the database

used is ms access. The name of the DSN is swa.


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Since the language used involves java codes this application can be used on windows as

well as on the Linux platform.Advantages of using jsp and ms access database are mentioned later in our section.The web server used to create an environment for running jsp files is Jakarta ApacheTomcat server and the jdk is also been used to execute java codes. The pages are created and designed using HTML.

Different Kinds of Server

First on our tour of the web, let's see what the different types of existing server look like

using a W3 browser. (For the fancy demos, skip ahead)

FTP

An FTP server, for example, is simply presented as a hypertext list. The user does nothave to know anything about FTP. This example is a server which has postscripts copies

of preprints of physics papers. We can follow through the directory structure to the

preprints directory, to the preprints from Rice, into the ps directory which I happen toknow contains postscript files, and find a particular preprint of a physics paper.

Gopher

Looking at a Gopher server is very similar. Gopher is like WWW except that there is nohypertext: anything is either a plain document or a menu. Here we see an example of a

gopher menu, and you can see that there are extra menu items which have beenintroduced to look like headings.

News

When a WWW browser reads news, it uses hypertext to give instant links between

related articles and newsgroups. Looking for example at WWW's own newsgroup,comp.infosystems.www, let's select a reply message -- one starting with "Re: [I can't

leave you a link to this as news messages are deleted with time , so you have to pick

one.] Notice that at the top of the article there is a link back to the newsgroup. Also,there is a link to any article references. If you are lucky with your choice, you will see a

link within the text "in article , somebody writes". This is a good example of W3

software making links out of existing information.

W3 servers


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Lastly, let us look at some real hypertext specifically written for W3. Here is the "STING"

Software technology Interest Group service. We are presented with various options as tohow we would like to search for data. Let's suppose we want to know what "objective"

means in "objective C". We first select STING and give "Objective" as a search word. We

get back a summary of what STING has found for us.

As STING is relatively intelligent, it gives us pointers to other good places to look too.

We chose the software engineering glossary entry. This, like the search results, is a"virtual" hypertext document, in that it has been generated on the fly by a server. Itisn't written in a disk file anywhere. It is relatively easy to write servers to generatehypertext spaces like this, allowing complex information to be very simply presented to a

user with no special skills.

We have seen how a W3 client gives access to a vast range of existing data from existingservers, but how the hypertext data from HTTP (native W3) servers is a much richer and

easier to explore.

Application server, Web server: What's the difference?

What is the difference between an application server and a Web server?

Taking a big step back, a Web server serves pages for viewing in a Web browser , whilean application server provides methods that client applications can call. A little more

precisely, you can say that:

A Web server exclusively handles HTTP requests, whereas an application server serves

business logic to application programs through any number of protocols.

Let's examine each in more detail.

The Web server

A Web server handles the HTTP protocol. When the Web server receives an HTTPrequest, it responds with an HTTP response, such as sending back an HTML page. To

process a request, a Web server may respond with a static HTML page or image, send a

redirect, or delegate the dynamic response generation to some other program such asCGI scripts, JSPs (Java Server Pages),Servelets, ASPs (Active Server Pages), server-

side Java Scripts, or some other server-side technology. Whatever their purpose, suchserver-side programs generate a response, most often in HTML, for viewing in a Web

browser.

Understand that a Web server's delegation model is fairly simple. When a request comesinto the Web server, the Web server simply passes the request to the program best ableto handle it. The Web server doesn't provide any functionality beyond simply providingan environment in which the server-side program can execute and pass back the

generated responses. The server-side program usually provides for itself such functionsas transaction processing, database connectivity, and messaging.


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While a Web server may not itself support transactions or database connection pooling ,

it may employ various strategies for fault tolerance and scalability such as loadbalancing, caching, and clusteringfeatures oftentimes erroneously assigned as features

reserved only for application servers.

The application server

As for the application server, according to our definition, an application server exposesbusiness logic to client applications through various protocols, possibly including HTTP.

While a Web server mainly deals with sending HTML for display in a Web browser, an

application server provides access to business logic for use by client applicationprograms. The application program can use this logic just as it would call a method on

an object (or a function in the procedural world).

Such application server clients can include GUIs (graphical user interface) running on a

PC, a Web server, or even other application servers. The information traveling back andforth between an application server and its client is not restricted to simple display

markup. Instead, the information is program logic. Since the logic takes the form of dataand method calls and not static HTML, the client can employ the exposed business logichowever it wants.

In most cases, the server exposes this business logic through a component API, such as

the EJB (Enterprise Java Bean) component model found on J2EE (Java 2 Platform,Enterprise Edition) application servers. Moreover, the application server manages its own

resources. Such gate-keeping duties include security, transaction processing, resource

pooling, and messaging. Like a Web server, an application server may also employvarious scalability and fault-tolerance techniques.

An example

As an example, consider an online store that provides real-time pricing and availability

information. Most likely, the site will provide a form with which you can choose aproduct. When you submit your query, the site performs a lookup and returns the results

embedded within an HTML page. The site may implement this functionality in numerous

ways. I'll show you one scenario that doesn't use an application server and another thatdoes. Seeing how these scenarios differ will help you to see the application server's

function.

Scenario 1: Web server without an application server

In the first scenario, a Web server alone provides the online store's functionality. The

Web server takes your request, then passes it to a server-side program able to handlethe request. The server-side program looks up the pricing information from a database

or a flat file. Once retrieved, the server-side program uses the information to formulate

the HTML response, then the Web server sends it back to your Web browser.


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To summarize, a Web server simply processes HTTP requests by responding with HTML

pages.

Scenario 2: Web server with an application server

Scenario 2 resembles Scenario 1 in that the Web server still delegates the responsegeneration to a script. However, you can now put the business logic for the pricing

lookup onto an application server. With that change, instead of the script knowing howto look up the data and formulate a response, the script can simply call the application

server's lookup service. The script can then use the service's result when the script

generates its HTML response.

In this scenario, the application server serves the business logic for looking up aproduct's pricing information. That functionality doesn't say anything about display or

how the client must use the information. Instead, the client and application server send

data back and forth. When a client calls the application server's lookup service, theservice simply looks up the information and returns it to the client.

By separating the pricing logic from the HTML response-generating code, the pricing

logic becomes far more reusable between applications. A second client, such as a cashregister, could also call the same service as a clerk checks out a customer. In contrast,

in Scenario 1 the pricing lookup service is not reusable because the information is

embedded within the HTML page.

To summarize, in Scenario 2's model, the Web server handles HTTP requests byreplying with an HTML page while the application server serves application logic by

processing pricing and availability requests.

Recently, XML Web services have blurred the line between application servers and Web

servers. By passing an XML payload to a Web server, the Web server can now processthe data and respond much as application servers have in the past.

Additionally, most application servers also contain a Web server, meaning you canconsider a Web server a subset of an application server. While application serverscontain Web server functionality, developers rarely deploy application servers in that

capacity. Instead, when needed, they often deploy standalone Web servers in tandemwith application servers. Such a separation of functionality aids performance (simpleWeb requests won't impact application server performance), deployment configuration(dedicated Web servers, clustering, and so on), and allows for best-of-breed product

selection.

Types of Database


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A lot of the sites that we visit on the web today are generated by a script of some

description, and a great deal of them will use a database in one form or another. Like itor loathe it, building pages dynamically from databases is a technique that is here to

stay.

There are two main types of database; flat-file and relational. Which is the best one touse for a particular job will depend on factors such as the type and the amount of data

to be processed; not to mention how frequently it will be used.

Flat-File

The flat-file style of database are ideal for small amounts of data that needs to be

human readable or edited by hand. Essentially all they are made up of is a set of stringsin one or more files that can be parsed to get the information they store; great for

storing simple lists and data values, but can get complicated when you try to replicate

more complex data structures.

That's not to say that it is impossible to store complex data in a flat-file database; justthat doing so can be more costly in time and processing power compared to a relational

database. The methods used for storing the more complex data types, are also likely torender the file unreadable and un-editable to anyone looking after the database.

The typical flat-file database is split up using a common delimiter. If the data is simple

enough, this could be a comma, but more complex strings are usually split up using

tabs, new lines or a combination of characters not likely to be found in the record itself.

One of the main problems with using flat files for even a semi-active database is the factthat it is very prone to corruption. There is no inherent locking mechanism that detectswhen a file is being used or modified, and so this has to be done on the script level. Even

if care is taken to lock and unlock the file on each access, a busy script can cause a "racecondition" and it is possible for a file to be wiped clean by two or more processes that

are fighting for the lock; the timing of your file locks will become more and moreimportant as a site gets busy.

Database Management (DBM)

The Database Management Layer allows script programmers to store information as a

pair of strings; a key, which is used to find the associated value. Essentially, a DBM adds


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more functionality and better sortation during storage to the binary flat-files that it uses.

There are several versions of DBMs available, but the most popular is the BerkleyDatabase Manager; also known as the Berkley DB.

The Berkley DB is an improvement over normal flat-files, as it provides a way for

programmers to use the database without having to worry about how the data is storedor how to retrieve the values. Retrieval of data using the Berkley DB is often much faster

than from a flat-file, with the time savings being made by storing data in a way that

speeds up the locating of a specific key-value pair.

Creating, editing and deleting data when using the Berkley DB is actually quite simple;once the database has been tied to the script you just use and manipulate the variables

as normal. The problem of file locking that plagues flat-file databases is still apparent

when using DBM, so you should still take care when planning scripts that utilize it.

Relational

The relational databases such as MySQL, Microsoft SQL Server and Oracle, have a muchmore logical structure in the way that it stores data. Tables can be used to represent real

world objects, with each field acting like an attribute. For example, a table called bookscould have the columns title, author and ISBN, which describe the details of each book

where each row in the table is a new book.

The "relation" comes from the fact that the tables can be linked to each other , for

example the author of a book could be cross-referenced with the authors table(assuming there was one) to provide more information about the author. These kind of

relations can be quite complex in nature, and would be hard to replicate in the standardflat-file format.

One major advantage of the relational model is that, if a database is designed efficiently,there should be no duplication of any data; helping to maintain database integrity. This

can also represent a huge saving in file size, which is important when dealing with largevolumes of data. Having said that, joining large tables to each other to get the data

required for a query can be quite heavy on the processor; so in some cases, particularly

when data is read only, it can be beneficial to have some duplicate data in a relational

database.

Relational databases also have functions "built in" that help them to retrieve, sort and

edit the data in many different ways. These functions save script designers from having

to worry about filtering out the results that they get, and so can go quite some way tospeeding up the development and production of web applications.


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Database Comparisons

In most cases, you would want your database to support various types of relations;

such databases, particularly if designed correctly, can dramatically improve the speed ofdata retrieval as well as being easier to maintain. Ideally, you will want to avoid the

replication of data within a database to keep a high level of integrity, otherwise changesto one field will have to be made manually to those that are related.

While several flat-files can be combined in such a way as to be able to emulate some of

the behaviors of a relational database, it can prove to be slower in practice. A single

connection to a relational database can access all the tables within that database;whereas a flat file implementation of the same data would result in a new file open

operation for each table.

All the sorting for flat-file databases need to be done at the script level. Relational

databases have functions that can sort and filter the data so the results that are sent tothe script are pretty much what you need to work with. It is often quicker to sort the

results before they are returned to the script than to have them sorted via a script , fewscripting languages are designed to filter data effectively and so the more functions a

database supports, the less work a script has to do.

If you are only working with a small amount of data that is rarely updated then a fullblown relational database solution can be considered overkill. Flat-file databases are notas scaleable as the relational model, so if you are looking for a suitable database for

more frequent and heavy use then a relational database is probably more suitable.

ABOUT DATABASE USED:In our ms access database there are total of twelve tables used:

1. User: This table contains two attributes username and password, both of themhaving their data type as text.

2. Suggestion,Share,Share the implementation (sh_imp): These tables contains a totalof seven attributes s_id in suggestion, sh_id in share and sh_imp_id in share the

implementation .Data type of all the three attributes is number.Matter,subject,dated,no_of_links,deptt_id and no_of_upload are the common fields orattributes in all the three tables mentioned above ,matter is of data type memo and restof all i.e. subject,dated,no_of_links,deptt_id and no_of_upload have their data type as

text.


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3.Link_s,Link_sh and Link_sh_imp: These tables contains two attributes, the links of

suggestion, share and share the implementation respectively as url and theirrespective id as s_id, sh_id and sh_imp_id.Both id and url have text as their data type.

4. Upload_s, Upload_sh and Upload_sh_imp: These tables contain two attributes, the

path of the uploaded matter and their respective id as s_id, sh_id and sh_imp_id. Data type of id is memo and s_id, sh_id and sh_imp_id have text as their data type astext.

5. User1: This table contains three attributes deptt_id, username and password. All of three have text as their data type.

6. Department (deptt): This table has two fields or attributes deptt_id and deptt_name. Text is their data type.

What Are Java Server Pages? Put succinctly, Java Server Pages is a technology for developing web pages that include

dynamic content. Unlike a plain HTML page, which contains static content that alwaysremains the same, a JSP page can change its content based on any number of variable

items, including the identity of the user, the user's browser type, information providedby the user, and selections made by the user. As you'll see later in the book, this

functionality is key to web applications such as online shopping and employee

directories, as well as for personalized and internationalized content.

A JSP page contains standard markup language elements, such as HTML tags, just like aregular web page. However, a JSP page also contains special JSP elements that allow the

server to insert dynamic content in the page. JSP elements can be used for a variety ofpurposes, such as retrieving information from a database or registering userpreferences. When a user asks for a JSP page, the server executes the JSP elements,

merges the results with the static parts of the page, and sends the dynamically

composed page back to the browser.

Generating dynamic content with JSP elements:

JSP defines a number of standard elements that are useful for any web application, suchas accessing JavaBeans components, passing control between pages and sharing

information between requests, pages, and users. Developers can also extend the JSPsyntax by implementing application-specific elements that perform tasks such as

accessing databases and Enterprise JavaBeans, sending email, and generating HTML to

present application-specific data. One such set of commonly needed custom elements is


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defined by a specification related to the JSP specification: the JSP Standard Tag Library

(JSTL) specification. The combination of standard elements and custom elements allowsfor the creation of powerful web applications.

Why Use JSP?

In the early days of the Web, the Common Gateway Interface (CGI) was the only tool for

developing dynamic web content. However, CGI is not an efficient solution. For everyrequest that comes in, the web server has to create a new operating-system process,

load an interpreter and a script, execute the script, and then tear it all down again. This

is very taxing for the server and doesn't scale well when the amount of traffic increases.

Numerous CGI alternatives and enhancements, such as FastCGI, mod_perl from Apache,NSAPI from Netscape, ISAPI from Microsoft, and Java Servelets from Sun Microsystems,

have been created over the years. While these solutions offer better performance and

scalability, all these technologies suffer from a common problem: they generate webpages by embedding HTML directly in programming language code. This pushes thecreation of dynamic web pages exclusively into the realm of programmers. Java Server

Pages, however, changes all that.

What You Need to Get Started

Before we begin, let's quickly run through what you need to run the examples and

develop your own applications. You really only need three things:

y A PC or workstation, with a connection to the Internet so you can download thesoftware you need

y A Java 2 compatible-Java Software Development Kit (Java 2 SDK)y A JSP 2.0-enabled web server, such as Apache Tomcat from the Jakarta Project

The Apache Tomcat server is the reference implementation for JSP. All the examples inthe book were tested on Tomcat.

Servelets

The JSP specification is based on the Java servlet specification. In fact, JSP pages are

often combined with servlets in the same application. In this section, we take a brief look

at what a servlet is, and then discuss the concepts shared by Servelets and JSP pages.

Advantages over Other Server-Side Technologies

In simple terms, a servlet is a piece of code that adds new functionality to a server(typically a web server), just like CGI and proprietary server extensions such as NSAPI

and ISAPI. But compared to other technologies, servlets have a number of advantages:


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Platform and vendor independence All the major web servers and application servers support servlets, so a servlet-

based solution doesn't tie you to one specific vendor. Also, servlets are written inthe Java programming language, so they can be used on any operating system

with a Java runtime environment.

IntegrationServlets are developed in Java and can therefore take advantage of all other Javatechnologies, such as JDBC for database access, JNDI for directory access, RMI

for remote resource access, etc. Starting with Version 2.2, the servlet

specification is part of the Java 2 Enterprise Edition (J2EE), making servlets animportant ingredient of any large-scale enterprise application, with formalized

relationships to other server-side technologies such as Enterprise JavaBeans.

EfficiencyServlets execute in a process that is running until the servlet-based application is

shut down. Each servlet request is executed as a separate thread in thispermanent process. This is far more efficient that the CGI model, where a new

process is created for each request. First of all (and most obvious), a servletdoesn't have the overhead of creating the process and loading the CGI script and

possibly its interpreter. But another timesaver is that servlets can also access

resources that remain loaded in the process memory between requests, such asdatabase connections and persistent state.

ScalabilityBy virtue of being written in Java and the broad support for servlets, a servlet-

based application is extremely scalable. You can develop and test the application

on a Windows PC using the standalone servlet reference implementation, anddeploy it on anything from a more powerful server running Linux and Apache to a

cluster of high-end servers with an application server that supports loadbalancingand failover.

Robustness and securityJava is a strongly typed programming language. This means that you catch a lot

of mistakes in the compilation phase that you would only catch during runtime if

you used a script language such as Perl. Java's error handling is also much morerobust than C/C++, where an error such as division by zero typically brings down

the whole server.

In addition, servlets use specialized interfaces to server resources that aren't

vulnerable to the traditional security attacks. For instance, a CGI Perl scripttypically uses shell command strings composed of data received from the client to


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ask the server to do things such as send email. People with nothing better to do

love to find ways to send data that will cause the server to crash, remove all fileson the hard disk, or plant a virus or a backdoor when the server executes the

command. While a CGI script programmer must be very careful to screen all input

to avoid these threats, such problems are almost nonexistent with a servletbecause it doesn't communicate with the server in the same insecure way.

Servlet Containers

A servlet container is the connection between a web server and the servlets. It provides

the runtime environment for all the servlets on the server as defined by the servletspecification, and is responsible for loading and invoking those servlets when the time is

right.

The container typically loads a servlet class when it receives the first request for the

servlet, gives it a chance to initialize itself, and then asks it to process the request.Subsequent requests use the same, initialized servlet until the server is shut down. Thecontainer then gives the servlet a chance to release resources and save its state (for

instance, information accumulated during its lifetime).

There are many different types of servlet containers. Some containers are called add-ons, or plug-ins, and are used to add servlet support to web servers without nativeservlet support (such as Apache and IIS). They can run in the same operating-systemprocess as the web server or in a separate process. Other containers are standaloneservers.

A standalone server includes web server functionality to provide full support for HTTP in

addition to the servlet runtime environment. Containers can also beembedded in otherservers, such as a climate-control system, to offer a web-based interface to the system.

A container bundled as part of an application server can distribute the execution of

servlets over multiple hosts. The server can balance the load evenly over all containers ,

and some servers can even provide failover capabilities in case a host crashes.

No matter what type it is, the servlet container is responsible for mapping an incoming

request to a servlet registered to handle the resource identified by the URI and passingthe request message to that servlet. After the request is processed, it's the container's

responsibility to convert the response created by the servlet into an HTTP response

message and send it back to the client.

JSP Overview

JSP is the latest Java technology for web application development and is based on theservlet technology introduced in the previous chapter. While servlets are great in many

ways, they are generally reserved for programmers. In this chapter, we look at the

problems that JSP technology solves, the anatomy of a JSP page, the relationshipbetween servlets and JSP, and how the server processes a JSP page.

In any web application, a program on the server processes requests and generates

responses. In a simple one-page application, such as an online bulletin board, you don'tneed to be overly concerned about the design of this piece of code; all logic can be

lumped together in a single program. However, when the application grows into


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something bigger (spanning multiple pages, using external resources such as databases,

with more options and support for more types of clients), it's a different story.

The way your site is designed is critical to how well it can be adapted to newrequirements and continue to evolve. The good news is that JSP technology can be used

as an important part in all kinds of web applications, from the simplest to the mostcomplex. Therefore, this chapter also introduces the primary concepts in the design

model recommended for web applications and the different roles played by JSP and otherJava technologies in this model.

JSP Processing

Just as a web server needs a servlet container to provide an interface to servlets, the

server needs a JSP container to process JSP pages. The JSP container is responsible forintercepting requests for JSP pages. To process all JSP elements in the page, thecontainer first turns the JSP page into a servlet (known as

the JSP page implementation class). The conversion is pretty straightforward; all

template text is converted to println( ) statements similar to the ones in the hand codedservlet, and all JSP elements are converted to Java code that implements thecorresponding dynamic behavior. The container then compiles the servlet class.

Converting the JSP page to a servlet and compiling the servlet form

thetranslation phase. The JSP container initiates the translation phase for a pageautomatically when it receives the first request for the page. Since the translation phase

takes a bit of time, the first user to request a JSP page notices a slight delay. Thetranslation phase can also be initiated explicitly; this is referred to as precompilation of a

JSP page. Precompiling a JSP page is a way to avoid hitting the first user with this delay.The JSP container is also responsible for invoking the JSP page implementation class (thegenerated servlet) to process each request and generate the response. This is calledtherequest processing phase.

As long as the JSP page remains unchanged, any subsequent request goes straight to

the request processing phase (i.e., the container simply executes the class file). Whenthe JSP page is modified, it goes through the translation phase again before entering the

request processing phase.

The JSP container is often implemented as a servlet configured to handle all requests forJSP pages. In fact, these two containersa servlet container and a JSP containerare

often combined in one package under the name webcontainer.

So in a way, a JSP page is really just another way to write a servlet without having to be

a Java programming wiz. Except for the translation phase, a JSP page is handled exactlylike a regular servlet; it's loaded once and called repeatedly, until the server is shut

down. By virtue of being an automatically generated servlet, a JSP page inherits all theadvantages of a servlet, platform and vendor independence, integration, efficiency ,scalability, robustness, and security.

JSP Elements

There are three types of JSP elements you can use: directive, action, andscripting. A

new construct added in JSP 2.0 is an Expression Language (EL) expression; let's call this

a forth element type, even though it's a bit different than the other three.


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Directive elements

The directive elements, shown in following table, specify information about the page

itself that remains the same between requestsfor example, if session tracking isrequired or not, buffering requirements, and the name of a page that should be used to

report errors, if any.

Directive elementsElement Description

Defines page-dependent attributes, such as session tracking, error

page, and buffering requirements Includes a file during the translation phaseDeclares a tag library, containing custom actions, that is used in thepage

Custom action elements and the JSP Standard Tag Library

In addition to the standard actions, the JSP specification defines how to

develop custom actions to extend the JSP language, either as Java classes or as text files

with JSP elements. The JSP Standard Tag Library (JSTL) is such an extension, with thespecial status of being defined by a formal specification from Sun and typically bundled

with the JSP container. JSTL contains action elements for the type of processing needed

in most JSP applications, such as conditional processing, database access,internationalization, and more. This book covers all the JSTL actions in detail.

If JSTL isn't enough, your team (or a third party) can use these extension mechanisms

to develop additional custom actions, maybe to access application-specific resources orsimplify application-specific processing. The examples in this book use a few customactions in addition to the JSTL actions.

Scripting elements

Scripting elements, shown in Table, allow you to add small pieces of code (typically Java

code) in a JSP page, such as an if statement to generate different HTML depending on acertain condition. Like actions, they are also executed when the page is requested. You

should use scripting elements with extreme care: if you embed too much code in your

JSP pages, you will end up with the same kind of maintenance problems as with servletsembedding HTML.

Scripting elementsElement Description Scriplets, used to embed scripting code

Expression, used to embed scripting code expressions when the result shallbe added to the response; also used as request-time action attribute values


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Scripting elementsElement Description

Declaration, used to declare instance variables and methods in the JSP page

implementation class

Expression Language expressions

A new feature in JSP 2.0 is the Expression Language (EL), originally developed as part of

the JSTL specification. The EL is a simple language for accessing request data and datamade available through application classes. EL expressions can be used directly in

template text or to assign values to action element attributes. Its syntax is similar to

JavaScript, but much more forgiving; it's constrained in terms of functionality, since it'snot intended to be a full-fledged programming language. Rather, it is a glue for tying

together action elements and other application components. There are way too manyelements of the EL to list here.

JavaBeans components

JSP elements, such as action and scripting elements, are often used to workwith JavaBeans components. Put succinctly, a JavaBeans component is a Java class that

complies with certain coding conventions. JavaBeans components are typically used ascontainers for information that describes application entities, such as a customer or an

order.

Setting Up the JSP Environment

This book contains plenty of examples to illustrate all the JSP features. All exampleswere developed and tested with the JSP reference implementation, known as theApache Tomcat server, which is developed by the Apache Jakarta project. In this chapter

you will learn how to install the Tomcat server and add a web application containing all

the examples used in this book. You can, of course, use any web server that supportsJSP 2.0, but Tomcat is a good server for development and test purposes.

Installing the Java Software Development Kit

Tomcat 5 is a pure Java web server with support for the Servlet 2.4 and JSP 2.0

specifications. In order to use it, you must first install a Java runtime environment.

I recommend that you download and install the Java 2 SDK (a.k.a. JDK), as opposed to

the slimmed-down Runtime Environment (JRE) distribution. The reason is that JSPrequires a Java compiler, included in the SDK but not in the JRE.

Another alternative is to use the JRE plus the Jikes compiler from IBM. Tomcat can be

configured to use Jikes instead of the javac compiler available in the Java 2 SDK fromSun; read the Tomcat documentation if you would like to try this. To make things

simple, though, I suggest installing the Java 2 SDK from Sun. The examples were

developed and tested with Java 2 SDK,Standard Edition, v1.4.2. I suggest that you usethe latest version of the SDK available for your platform.


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If you need an SDK for a platform other than Windows, Linux, or Solaris, there's a partial

list of ports made by other companies.

Also check your operating-system vendor's web site. Most operating-system vendorshave their own SDK implementation available for free.

Installation of the SDK varies per platform but is typically easy to do. Just follow the

instructions on the web site where you download the SDK.

Before you install and run Tomcat, make sure that the JAVA_HOME environment variableis set to the installation directory of your Java environment and that the

Java bin directory is included in the PATH environment variable. On a Windows system,

you can see if an environment variable is set by typing the following command in aCommand Prompt window:

C:\> echo %JAVA_HOME%

C:\jdk1.4.2

If JAVA_HOME isn't set, you can set it and include the bin directory in the PATH on a

Windows system like this (assuming Java is installed in C:\jdk1.4.2):

C:\> set JAVA_HOME=C:\jdk1.4.2

C:\> set PATH=%JAVA_HOME%\bin;% PATH%

On a Windows 95/98/ME system, add these commands to theC:\AUTOEXEC.BAT file to

set them permanently. Just use a text editor, such as Notepad, and add lines with

the set commands. The next time you boot the PC, the environment variables will be set

automatically. For Windows NT, you can set them permanently fromthe Environment tab in the System Propertiestool in the Control Panel, and for Windows

2000 and Windows XP, you can do the same with the Control Panel System tool by firstselecting the advancedtab and then Environment Variables.

Installing the Tomcat Server

Tomcat supports many features and configuration options. In this section, I onlydescribe the basics that you must know to get Tomcat up and running. If you plan to use

Tomcat extensively for development or as a production server, refer to Tomcat: TheDefinitive Guide by Jason Brittain and Ian Darwin (O'Reilly).

You can download the Tomcat server in binary format or as source code that you compile

yourself. If you're primarily interested in learning about JSP, I recommend that you use

the binary download for running the examples in this book and to develop your ownapplications. If you're a Java programmer and are interested in seeing how Tomcat is

implemented, feel free to download the source as well and take a look at the internals.

On this page you find three types of builds: release builds, milestone builds, and nightly

builds. Release builds are stable releases that have been tested extensively and verifiedto comply with the servlet and JSP specifications.Milestone builds are created as

intermediary steps towards a release build. They often contain new features that aren'tyet fully tested but are generally known to work. A nightly build, however, may be very

unstable. It's actually a snapshot of the latest source code and may have been tested


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only by the person who made the latest change. You should use a nightly build only if

you're involved in the development of Tomcat.

Testing Tomcat

The Tomcat installation directory contains a number of subdirectories. All of them aredescribed in the README.txt file, but the most important ones are:

binScripts for starting and stopping the Tomcat server.

confTomcat configuration files.

webappsDefault location for web applications served by Tomcat.

Two more subdirectories under the Tomcat home directory are created the first time you

start the server:

logsServer log files. If something doesn't work as expected, look in the files in this

directory for clues as to what's wrong.

workA directory for temporary files created by the JSP container and other files. This

directory is where the servlets generated from JSP pages are stored.

5.4.1 JSP Comments

JSP comment looks like:

Everything between is ignored when the JSP page is processed. You can

use this type of comment to describe what's going on in the page or to temporarilycomment out pieces of the page to test different alternatives. Since a JSP comment is a

JSP element, it's never sent to the browser.


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familiar with XML syntax, you may recognize that the prefix is used as an XML

namespace. You define the namespace prefix you want to use for the library withthe taglib directive described earlier:

...

The prefix serves two purposes: it makes it possible for actions in different libraries to

have the same name, and it makes it possible for the container to figure out to which

library a specific action belongs. When the container finds an action element, it locatesthe taglib directive that declares the library that corresponds to the action name prefix.

The taglib directive's uri attribute is a unique identifier for the tag library, which thecontainer uses to find the information it needs to process the action.

Actions can be grouped into three categories: standard, custom, and JSP Standard TagLibrary.

Standard actions are the actions defined by the JSP specification itself.Following table

lists all standard actions that you can use in a regular JSP page. The JSP standardactions use the prefix jsp. Since the prefix is fixed, and the behavior for all standard

actions is defined by the specification, you don't declare the standard actions with

a taglib directive.

Standard action elementsAction element Description

Makes a JavaBeans component available in a page Gets a property value from a JavaBeans component and adds it to

the response

Set a JavaBeans property value Includes the response from a servlet or JSP page during the request

processing phase

Forwards the processing of a request to a servlet or JSP page Adds a parameter value to a request handed off to another servlet

or JSP page using or Generates HTML that contains the appropriate browser-dependent

elements (OBJECT or EMBED) needed to execute an applet with theJava Plugin software

Sets the value of an action attribute based on the body of thiselement

Sets the action element body based on the body of this element.Required when the action element body

contains action elements


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Standard action elementsAction element Description

Dynamically generates an XML element, optionally with attributes

and a body defined by

nested and actions Used to encapsulate template text that should be used verbatim;

typically only needed in JSP pages written as XML documents The JSP specification also defines how to develop new actions that can be used in any

JSP page. Such actions are called custom actions.

The JSP Expression Language

Expression Language operators Operator Operation performed.

Access a bean property or Map entry

[]Access an array or List element

( )Group a subexpression to change the evaluation order

? :Conditional test: condition ? ifTrue : ifFalse

+Addition

-Subtraction or negation of a value

*Multiplication

/ or div Division% or mod Modulo (remainder)== or eq Test for equality!= or ne Test for inequality< or lt Test for less than> or gt Test for greater than= or ge Test for greater than or equal && or and Test for logical AND|| or or Test for logical OR! or not Unary Boolean complementempty Test for empty variable values (null, an empty String or an array,Map,


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Expression Language operators Operator Operation performed

or Collection without entries)func(arg) A function call, where funcis the function name and arg is a function

argumentAn EL expression can also contain variables. Variables are named references to data

(objects), created by the application or made available implicitly by the EL.

Accessing a Database

Almost all the web applications that you see on the Internet access a database.

Databases store customer information, order information, product information, evendiscussion forum messagesin short, all information that needs to survive a server

restart and is too complex to handle in plain-text files.

There are many types of databases used in the industry today. However, relational

databases are by far the most common. A relational database uses tables to representthe information it handles. A table consi sts of rows of columns, with each column holding

a single value of a predefined data type. Examples of these data types are text data,numeric data, dates, and binary data such as images and sound. A specialized language

called Structured Query Language (SQL) is used to access the data. SQL is an ANSI

standard and is supported by all major database vendors.

Relational database engines come in all shapes and sizes, from simple one-persondatabases with limited features, to sophisticated databases capable of handling largenumbers of concurrent users with support for transactions distributed over multipleservers and extremely optimized search algorithms.

Even though they all use SQL as the data access language, the API used to execute SQL

statements is different for each database engine. To help programmers write code that'sportable between database engines, the standard Java libraries include an API called theJava Database Connectivity (JDBC) API. JDBC defines a set of classes that can executeSQL statements the same way in any relational database.

The complexity of databases varies extensively. A database for an online discussion

forum, for instance, requires only one or two tables, while a database for a humanresources system may contain hundreds of related tables. In this chapter , we look at a

set of JSTL database actions you can use to build any type of database -driven web

application.

But if the database is complex, you may want to use another approach: hiding thedatabase behind application-specific beans and custom actions, or moving all database

processing to a servlet and using JSP only to show the result.

Accessing a Database from a JSP Page

JSTL includes a number of actions for database access to make it easy to develop simpledatabase-driven JSP applications. The actions provide the following features:

y Using a connection pool for better performance and scalability

y Supporting queries, updates, and inserts


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y Handling the most common data type conversions

y Supporting a combination of database operations in one transaction

Using Scriptlets

The scriptlet element can be used to add a whole block of code to a page, includingvariable declarations. The code block must be enclosed by a scriptlet start -

identifier, .Following example shows a scriptlet that

creates test data for action elements.

Example... Scriptlet creating test data (scriptlet.jsp)


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Search result: Authors

Here are all authors matching your search critera:

Name

Id

${fn:escapeXml(current.name)}

${fn:escapeXml(current.id)}

The scriptlet element contains Java code that creates

a java.util.ArrayList withjava.util.HashMap elements and saves the list as a page scopeattribute namedauthors by calling the setAttribute( ) method on the

implicit pageScope object. The ArrayList is then used as the items attribute value in

a action. You can use a scriptlet like this to test the main page functionalitybefore the real data.

JSP vs ASP

Introduction:

5-6 years back it was easy to choose a server-side language as CGI used to be only the

only scripting language available. But in due course of time, the developers found outthat CGI scripts were inefficient and it was very difficult to write server extensions.

At that time, Microsoft came up with Active Server Pages (ASP), which allows

developers to use simple scripting to access the server and its extensions. But ASP had

some disadvantages.


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It limits you to work on Microsoft platforms, and the simplest of mistakes in the script

can cause the server to crash or hang, effectively bringing down your website.

In response to ASP, Sun Microsystems gave the world Java Server Pages (JSP)technology, which is entirely based on Java programming language. Internally, JSP

pages are dynamically converted into Servelets, which are simply Java classes. Thismeans JSP enjoys all the capabilities that Java programming supports.

JSP is a great deal more efficient than many other scripting languages , such as CGI and

ASP. Tags can be defined in tag libraries and then used within any JSP page.

This makes for a better separation of page content from its code, which leads to less

scattered code and hence, the site is easier to maintain. Global changes need to bemade only to the tags defined in these tag libraries, making time-consuming, page-by-

page fixes things of the past.

JSP versus ASP

JSP and ASP have some basic concepts in common.

1) They both make use of simple sever-side scripting to provide access to Web serverinformation and functionality.

2) They both have similar styles of delimiting this scripting from a page's content. In

fact, Microsoft's has recently come up with ASP+ is much more similar to JSP than ASP.

Yet while ASP primarily supports two scripting languages, JScript and VBScript, JSP

actually supports real Java code, not a new scripting language. The difference is that theJava code inside a JSP page is more script-like because it doesn't require Java class and

package definitions. JScript, VBScript, and Java (in JSP) are all object oriented to somedegree as they are all provided with a set of pre-established objects by the Web serverthat they use to generate a dynamic Web page.

The following table lists some of the instantiated objects that are available in both ASP

and JSP.

JSP ASP Definition

Request Request Access to request information.

Response Response Access to response information.


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Session Session Access to session information.

Application Application Access to application information.

Out Response. Write Access to the response output stream

Note that JSP is case sensitive. But VBScript is not.

As I mentioned earlier, both ASP and JSP support a similar way of delimiting scripting

from content on a page. are used to set of sections of script , '' are used to return a value within content, and are used to delimit

page directives.

JSP supports two basic styles of delimiting its scripting elements from page content. Thefirst looks a great deal like ASP, whereas the second can be used to create JSP that is

fully XML compliant. Here, let's examine these styles:

Base Style XML Style Description

Directives are used to specify pageinformation, include other files, and specify tag libraries being used.

Declarative code

You can declare new methods using these tags.

Code fragment

This code is placed within a base method of the generated servlet.

Code expression

This code is appended to the output stream being returned for the page.

Conclusion

In many ways, the biggest difference between JSP and ASP technologies lies in the

approach to the software design itself.


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JSP technology is designed to be both platform and server independent, created with

input from a broader community of tool, server, and database vendors. In contrast, ASPis a Microsoft technology that relies primarily on Microsoft technologies.

Now as we have seen the advantages of JSP over ASP, I'll like to share some

information on JSP with you:

There are a number of servers that support JSP on the market. The popular ones areTomcat, Jrun and Enhydra.

Another powerful feature of JSP that we haven't covered in this article is its ability to

utilize JavaBeans with special tags defined in JSP. For more information about this, you

can refer to Sun's JavaBeans overview.

An Overview of the Technology

Comparing these two technologies is both a difficult and sensitive task but it isimportant to appreciate the differences in the way that the various interface, and the

applications that connect to them, work.

Java Server Pages (JSP) and Microsoft Active Server Pages (ASP) technologies provide a

simplified, fast way to create web pages that display dynamically generated content.While ASP and JSP technologies are similar in many ways, they also differ significantly in

some ways.

Both the technologies follow the same model of separating programming logic frompage design through the use of components that are called from the page itself. And

both provide developers an easier and faster alternative to creating web applications

using CGI scripts.

The biggest difference between JSP and ASP technologies lies in the approach to thesoftware design. ASP is based on ISAPI whereas JSP is implemented as a part of J2EE.

ASP consists of a single DLL (asp.dll) which generates dynamic content when an ASP

page with server-side script combined with HTML is parsed through it. Similarly, the JSP-enabled engine on the web server will process the JSP page, which may includetechnology-specific tags, declarations, and possibly Script lets in JAVA, along with HTMLor XML tags.

Here I have attempted to describe the main strengths of JSP as compared to ASP:

y Portability

A Portable application environment gives organizations the flexibility to migrate servers

and swap tools, as business needs change. Portability also enables developers to share

their work with a wider audience.

Java Server Pages technology delivers "Write Once, Run Anywhere" capability, offering

unprecedented reuse on any platform and on any server.

JSP is being developed through an industry-wide initiative led by Sun Microsystems and

is designed to be both platform and server independent. In contrast, ASP is purely aMicrosoft based technology deployed primarily on Windows NT servers.


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JSP technology was designed to support numerous servers, browsers and tools. Apache

web server, which hosts more than 70/% of the websites worldwide, will now fullysupport the JSP technology under the Jakarta Tomcat project.

So, having to hosting a web application on a robust UNIX OS with JSP is not a distant

dream. JSP is also being supported on the NT platform using third party components.

y Performance

Pages built using JSP technology are typically implemented using a translation phase

that is performed once, the first time the page is called. The page is compiled into a Java

Servlet class and remains in server memory, so subsequent calls to the page have veryfast response time whereas in ASP the page is recompiled for every request.

JSP implementations support a Java programming language-based scripting language,

which provides inherent scalability and support for complex operations.

Most JSP pages rely on reusable, cross-platform components (JavaBeans or EnterpriseJavaBeans TM components) to perform the more complex processing required of the

application, instead of relying heavily on scripting within the page itself. Developers canshare and exchange components that perform common operations, or make themavailable to larger customer communities. The component-based approach speedsoverall development and lets organizations leverage their existing expertise and

development efforts for optimal results.

The results of a performance test (ASP vs. JSP) done by a JSP enthusiast is available foryour comments - http://www.geocities.com/gslender/. Be sure the results would

improve if MySQL and UNIX were used in the test configuration.

y Development &Deployment Component-based Architecture

As mentioned earlier, JSP follows the model of separating programming logic from page

design through the use of components like JavaBeans, Enterprise JavaBeans (EJB) andcustom JSP tags.

Assuming that web page developers are not familiar with scripting languages, JSP

technology encapsulates much of the functionality required for dynamic content

generation in easy-to-use JavaBeans components. The page developer can instantiateJavaBeans components set or retrieve bean attributes and perform other functions that

are otherwise more difficult and time-consuming to code.

Microsoft's answer to component architecture relies on COM/DCOM to supplement theASP technology. Given the complexity involved in developing COM components in VC++or VB, it is by no means a comparison to the simplicity of JavaBeans , which can be

easily, developed using Java.

y Custom Tag Libraries

The JSP technology is extensible through the development of customized tag libraries.This lets web page developers work with familiar tools and constructs, such as tags, to


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perform sophisticated functions. ASP does not directly support custom tags like JSP but

supports XML.

y MVC (Model-View-Controller) or Model 2 Architecture

Separation of Presentation and Business Logic has never been so easy with ASP or JSP.

With increasing complexity the pages would clutter with Scriplets and processing code,making it hard to debug or make changes. To counter this problem, the JSP/Servlet's

Model 2 architecture was introduced, providing a cleaner approach to codemanageability.

This is a hybrid approach for serving dynamic content combining the use ofServelets

and JSP. It takes advantage of the strengths of both technologies: JSP is used to

generate the presentation layer and Servelets to perform process-intensive tasks.

The Servlet acts as the controller processing the requests, creating beans (models) orobjects used by the JSP, and depending on the user's actions, dispatches the appropriate

JSP page to the user. The JSP (view) page, which contains no processing logic, is simply

responsible for extracting and inserting the dynamic content from the Servlet into statictemplates.

Being an EX- diehard fan of Microsoft, from experience I have discovered the

JSP/Servelets Technology to be more than just an answer to Microsoft's ASP technology.

Conclusion

JSP has become more robust and scalable with the release of J2EE. With an ever -growing support for the Java technology the JSP solution is gaining prominence and

immense respect from the developer community. Its time to break free from the tyranny

of Microsoft and embrace the technology from the Open Source world.

WHAT IS HTML?

Hypertext Markup Language is the basic language used to write web pages. HTML is amark up language and not a full-blown programming language so is therefore essentially

static in nature. HTML is parsed by your web browser when a web page downloads and

consists of tags (commands to tell the browser how to render the text, where to load in

graphics etc on the web page) as well as the actual text.

There are certain things you'll need to get started. These are...

y A Text Editor


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Any text editor. If it can save in plain (ASCII) text, it will do. This means that anything

from Microsoft Word 6.0 to the DOS Edit program to Teach Text to UNIX vi will work. Allit has to do is save the documents in plain, flat, unstyled ASCII-style text.

y A Web Browser

Netscape Navigator, NCSA Mosaic, Microsoft Internet Explorer, Lynx, MacWeb/WinWeb,Cello, Chimera, Web Explorer, Net Cruiser, whatever. In fact, it's a good idea to keep

more than one browser around for testing purposes (more about that later).

y A Graphics Tool

This gets a bit trickier. Sure, you can draw pictures with no problem, but can you get

them into the right format? In order to include a picture in a Web page, it needs to be in

the Graphic Interchange Format (GIF). Adobe Photoshop will save indexed color files asGIF files, and there are a number of format converters on the market. Whatever you get,

make sure you can get your files A Graphics Tool

This gets a bit trickier. Sure, you can draw pictures with no problem, but can you get

them into the right format? In order to include a picture in a Web page, it needs to be inthe Graphic Interchange Format (GIF). Adobe Photoshop will save indexed color files as

GIF files, and there are into GIF.

y A Web Server

Strictly speaking, this is optional. You can write Web pages in a text editor, save them to

your machine's hard drive, and load the pages into your Web browser in order to seehow they look. You don't even need a network connection to do this. The option to load

pages from your hard drive is typically called something like "Open Local" (Mosaic) or

simply "Open File" (Netscape).

However, if you plan to publish your documents so the rest of the world can benefit fromthem, you'll need to put them on a Web server. As long as you're using a Windows-based PC, a Macintosh, or a UNIX box, and it's connected to the Internet, you can setyour machine up as a Web server. For example, the program Mac HTTP will let you turn

your Mac into a Web server. Check around to see if you can locate something for yourplatform of choice.

Documents

Suggestion Scheme System