Web Application Deployment & JDBC CSC 667, Spring 2004 Dr. Ilmi Yoon

Web Application Web Application Deployment & JDBCDeployment & JDBC

Web Application Web Application Deployment & JDBCDeployment & JDBC

CSC 667, Spring 2004CSC 667, Spring 2004

Dr. Ilmi YoonDr. Ilmi Yoon

Web Application

• With the release of the Java Servlet Specification 2.2

• Web Application is a collection of servlets, html pages, classes, and other resources that can be bundled and run on multiple containers from multiple vendors

• Each web application has one and only one ServletContext

• http://www.onjava.com/pub/a/onjava/2001/03/15/tomcat.html

• http://www.onjava.com/pub/a/onjava/2001/04/19/tomcat.html

Deployment

• Deployment descriptor (web.xml)• Web applications can be changed

without stopping the server• With a standardized deployment comes

standardized tools• Check

http://unicorn.sfsu.edu/~csc667/04-24/667_files/frame.htm for tips for Ant, TogetherSoft, Tomcat install & deployment

Table 1. The Web Application Directory Structure

Directory Contains

/onjava This is the root directory of the web application. All JSP and XHTML files are stored here.

/onjava/WEB-INF This directory contains all resources related to the application that are not in the document root of the application. This is where your web application deployment descriptor is located. Note that the WEB-INF directory is not part of the public document. No files contained in this directory can be served directly to a client.

/onjava/WEB-INF/classes This directory is where servlet and utility classes are located.

/onjava/WEB-INF/lib This directory contains Java Archive files that the web application depends upon. For example, this is where you would place a JAR file that contained a JDBC driver.

Installation & Setup

• Update CLASSPATH– Identify the Classes (jsp.jar,

jspengine.jar, servlet.jar, jasper.jar) to the java Compiler

– Unix• CLASSPATH=${TOMCAT_HOME}/webserver.jar• CLASSPATH=${CLASSPATH}:${TOMCAT_HOME}/webserver.jar• CLASSPATH=${CLASSPATH}:${TOMCAT_HOME}/lib/servlet/jar• CLASSPATH=${CLASSPATH}:${TOMCAT_HOME}/lib/jsper.jar• CLASSPATH=${CLASSPATH}:${TOMCAT_HOME}/examples/WEB-

INF/classes

– Windows• set CLASSPATH=.;dir\servlet.jar;dir\

jspengine.jar

Installation & Setup

• Compile and Install your servlets– Tomcat

• install_dir/webpages/WEB-INF/classes• install_dir/classes• install_dir/lib (non frequently changing

classes)• install_dir/webapps/ROOT/WEB-INF/classes

(3.1)

• Invoking the servlets– http://host:port/servlet/

Packagename.servetName use /servlet/ regardless the actual directory name

– Register servlet

Calling Servlets From a Browser

• The URL for a servlet has the following general form, where servlet-name corresponds to the name you have given your servlet:

http://machine-name:port/servlet/servlet-name

• Servlet URLs can contain queries, such as for HTTP GET requests. For example, if the servlet's name is bookdetails; the URL for the servlet to GET and display all the information about the bookstore's featured book is: http://localhost:8080/servlet/bookdetails?bookId=203

Web.xml – under WEB_INF

<web-app> <display-name>The OnJava <web-app> <display-name>The OnJava App</display-name> <session-App</display-name> <session-timeout>30</session-timeout> timeout>30</session-timeout> <servlet> <servlet> <servlet-name>TestServlet</servlet-<servlet-name>TestServlet</servlet-name> <servlet-name> <servlet-class>com.onjava.TestServlet</servlet-class>com.onjava.TestServlet</servlet-class> <load-on-startup>1</load-on-class> <load-on-startup>1</load-on-startup> <init-param> <param-startup> <init-param> <param-name>name</param-name> <param-name>name</param-name> <param-value>value</param-value> </init-value>value</param-value> </init-param> </servlet> </web-app>param> </servlet> </web-app>

Packing the Web Application

• Web ARchive file (WAR)• Command : jar cvf onjava.war .• Now you can deploy your web

application by simply distributing this file

Table 5. The Tomcat Directory Structure

/bin

/conf This directory contains the main configuration files for Tomcat. The two most important are the server.xml and the global web.xml.

/server This directory contains the Tomcat Java Archive files.

/lib This directory contains Java Archive files that Tomcat is dependent upon.

/logs This directory contains Tomcat's log files.

/src This directory contains the source code used by the Tomcat server. Once Tomcat is released, it will probably contain interfaces and abstract classes only.

/webapps All web applications are deployed in this directory; it contains the WAR file.

/work This is the directory in which Tomcat will place all servlets that are generated from JSPs. If you want to see exactly how a particular JSP is interpreted, look in this directory.

Steps Involved in Deploying a Web Application to Tomcat

1. Copy your WAR file to the TOMCAT_HOME/webapps directory.

2. Add a new Context entry to the TOMCAT_HOME/conf/server.xml file, setting the values for the path and docBase to the name of your web application.

3. <Context path="/onjava" docBase="onjava" debug="0" reloadable="true" />

If you look at the TOMCAT_HOME/webapps directory, you will see a new directory matching the name of your WAR file

JDBC

• Database– Collection of data

• DBMS– Database management system– Storing and organizing data

• SQL– Relational database– Structured Query Language

• JDBC– Java Database Connectivity– JDBC driver

Relational-Database Model

• Relational database– Table– Record– Field, column– Primary key

• Unique data

• SQL statement– Query– Record sets

Manipulating Databases with JDBC

• Connect to a database• Query the database• Display the results of the query

Connecting to and Querying a JDBC Data Source

• DisplayAuthors– Retrieves the entire authors table– Displays the data in a JTextArea

public class SQLGatewayServlet extends HttpServlet{

private Connection connection;

public void init() throws ServletException{ try{ Class.forName("org.gjt.mm.mysql.Driver"); String dbURL = "jdbc:mysql://localhost/murach"; String username = "root"; String password = ""; connection = DriverManager.getConnection( dbURL, username, password); }

Create Connection at Init()

public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException{

String sqlStatement = request.getParameter("sqlStatement"); String message = "";

try{ Statement statement = connection.createStatement(); sqlStatement = sqlStatement.trim(); String sqlType = sqlStatement.substring(0, 6); if (sqlType.equalsIgnoreCase("select")){ ResultSet resultSet = statement.executeQuery(sqlStatement); // create a string that contains a HTML-formatted result set message = SQLUtil.getHtmlRows(resultSet); } else { int i = statement.executeUpdate(sqlStatement); if (i == 0) // this is a DDL statement message = "The statement executed successfully."; else // this is an INSERT, UPDATE, or DELETE statement message = "The statement executed successfully.<br>" + i + " row(s) affected."; } statement.close(); }

From JDBC Example at course web page

public void init() throws ServletException{ connectionPool = MurachPool.getInstance(); }

public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException{

Connection connection = connectionPool.getConnection();

String firstName = request.getParameter("firstName"); String lastName = request.getParameter("lastName"); String emailAddress = request.getParameter("emailAddress"); User user = new User(firstName, lastName, emailAddress);

HttpSession session = request.getSession(); session.setAttribute("user", user);

String message = "";

Processing Multiple ResultSets or Update Counts

• Execute the SQL statements• Identify the result type

– ResultSets– Update counts

• Obtain result– getResultSet– getUpdateCount

JDBC 2.0 Optional Package javax.sql

• Package javax.sql– Included with Java 2 Enterprise Edition

• Interfaces in package javax.sql– DataSource– ConnectionPoolDataSource– PooledConnection– RowSet

Connection Pooling

• Database connection– Overhead in both time and resources

• Connection pools– Maintain may database connections– Shared between the application

clients

Relational DB and SQL statements

Relational DB and SQL statements

This section is self-study sectionThis section is self-study section

Relational-Database Model

Number Name Department Salary Location

23603 J ones 413 1100 New J ersey

24568 Kerwin 413 2000 New J ersey

34589 Larson 642 1800 Los Angeles

35761 Myers 611 1400 Orlando

47132 Neumann 413 9000 New J ersey

78321 Stephens 611 8500 Orlando

Row/Rec ord

Column/ FieldPrimary key

Relational-database structure of an Employee table.

Relational Database Overview: The books

Database

• Sample books database– Four tables

•Authors, publishers, authorISBN and titles

– Relationships among the tables

Relational Database Overview: The books Database

Field Description authorID Author’s ID number in the database. In the books database, this integer

field is defined as an autoincremented field. For each new record inserted in this table, the database automatically increments the authorID value to ensure that each record has a unique authorID. This field represents the table’s primary key.

firstName Author’s first name (a string). lastName Author’s last name (a string). Fig. 8.3 authors table from books. authorID firstName lastName 1 Harvey Deitel

2 Paul Deitel 3 Tem Nieto 4 Sean Santry Fig. 8.4 Data from the authors table of books.


Database (Cont.)

Field Description publisherID The publisher’s ID number in the database. This autoincremented

integer is the table’s primary-key field. publisherName The name of the publisher (a string). Fig. 8.5 publishers table from books.

publisherID publisherName 1 Prentice Hall

2 Prentice Hall PTG Fig. 8.6 Data from the publishers table of books.


Database (Cont.)

Field Description authorID The author’s ID number, which allows the database to associate

each book with a specific author. The integer ID number in this field must also appear in the authors table.

isbn The ISBN number for a book (a string). Fig. 8.7 authorISBN table from books.


DatabaseauthorID isbn authorID isbn 1 0130895725 2 0139163050

1 0132261197 2 013028419x 1 0130895717 2 0130161438 1 0135289106 2 0130856118 1 0139163050 2 0130125075 1 013028419x 2 0138993947 1 0130161438 2 0130852473 1 0130856118 2 0130829277 1 0130125075 2 0134569555 1 0138993947 2 0130829293 1 0130852473 2 0130284173 1 0130829277 2 0130284181 1 0134569555 2 0130895601 1 0130829293 3 013028419x 1 0130284173 3 0130161438 1 0130284181 3 0130856118 1 0130895601 3 0134569555 2 0130895725 3 0130829293 2 0132261197 3 0130284173 2 0130895717 3 0130284181 2 0135289106 4 0130895601 Fig. 8.8 Data from the authorISBN table of books.


Database (Cont.)

Field Description isbn ISBN number of the book (a string).

title Title of the book (a string). editionNumber Edition number of the book (an integer).

copyright Copyright year of the book (a string). publisherID Publisher’s ID number (an integer). This value must correspond to an

ID number in the publishers table. imageFile Name of the file containing the book’s cover image (a string). price Suggested retail price of the book (a real number). [Note: The prices

shown in this book are for example purposes only.] Fig. 8.9 titles table from books.


Database (Cont.)

authorISBN

authorID

isbn

authors

authorID

firstName

lastName

publishers

publisherID

publisherName

titles

isbn

title

editionNumber

copyright

publisherID

imageFile

price

1 1

1

Fig. 8.11 Table relationships in books.

Structured Query Language (SQL)

• SQL overview• SQL keywords

SQL keyword Description SELECT Select (retrieve) fields from one or more tables.

FROM Tables from which to get fields. Required in every SELECT. WHERE Criteria for selection that determine the rows to be retrieved. GROUP BY Criteria for grouping records. ORDER BY Criteria for ordering records. INSERT INTO Insert data into a specified table. UPDATE Update data in a specified table. DELETE FROM Delete data from a specified table. Fig. 8.12 SQL query keywords.

Basic SELECT Query

• Simplest format of a SELECT query– SELECT * FROM tableName

•SELECT * FROM authors

• Select specific fields from a table– SELECT authorID, lastName FROM authors

authorID lastName 1 Deitel

2 Deitel 3 Nieto 4 Santry Fig. 8.13 authorID and lastName from the authors table.

WHERE Clause

• specify the selection criteria– SELECT fieldName1, fieldName2, … FROM

tableName WHERE criteria• SELECT title, editionNumber, copyright

FROM titles

WHERE copyright > 1999

• WHERE clause condition operators– <, >, <=, >=, =, <>– LIKE

• wildcard characters % and _

WHERE Clause (Cont.)

•SELECT authorID, firstName, lastNameFROM authors

WHERE lastName LIKE ‘D%’

authorID firstName lastName 1 Harvey Deitel

2 Paul Deitel Fig. 8.15 Authors whose last name starts with D from the authors table.

WHERE Clause (Cont.)


WHERE lastName LIKE ‘_i%’

authorID firstName lastName 3 Tem Nieto

Fig. 8.16 The only author from the authors table whose last name contains i as the second letter.

ORDER BY Clause

• Optional ORDER BY clause– SELECT fieldName1, fieldName2, … FROM

tableName ORDER BY field ASC– SELECT fieldName1, fieldName2, … FROM

tableName ORDER BY field DESC

• ORDER BY multiple fields– ORDER BY field1 sortingOrder, field2

sortingOrder, …

• Combine the WHERE and ORDER BY clauses

ORDER BY Clause (Cont.)


ORDER BY lastName ASC

authorID firstName lastName 2 Paul Deitel

1 Harvey Deitel 3 Tem Nieto 4 Sean Santry Fig. 8.17 Authors from table authors in ascending order by lastName.



ORDER BY lastName DESC

authorID firstName lastName 4 Sean Santry

3 Tem Nieto 2 Paul Deitel 1 Harvey Deitel Fig. 8.18 Authors from table authors in descending order by lastName.



ORDER BY lastName, firstName


2 Paul Deitel 3 Tem Nieto 4 Sean Santry Fig. 8.19 Authors from table authors in ascending order by lastName

and by firstName.


•SELECT isbn, title, editionNumber, copyright, priceFROM titles WHERE title LIKE ‘%How to

Program’

ORDER BY title ASC isbn title edition-

Number copy-right

price

0130895601 Advanced Java 2 Platform How to Program 1 2002 69.95

0132261197 C How to Program 2 1994 49.95 0130895725 C How to Program 3 2001 69.95 0135289106 C++ How to Program 2 1998 49.95 0130895717 C++ How to Program 3 2001 69.95 0130161438 Internet and World Wide Web How to

Program 1 2000 69.95

0130284181 Perl How to Program 1 2001 69.95 0134569555 Visual Basic 6 How to Program 1 1999 69.95 0130284173 XML How to Program 1 2001 69.95 013028419x e-Business and e-Commerce How to

Program 1 2001 69.95

Fig. 8.20 Books from table titles whose title ends with How to Program in ascending order by title.

Merging Data from Multiple Tables: Joining

• Join the tables– Merge data from multiple tables into a single view– SELECT fieldName1, fieldName2, … FROM table1, table2

WHERE table1.fieldName = table2.fieldName– SELECT firstName, lastName, isbn FROM authors, authorISBN WHERE authors.authorID =

authorISBN.authorID ORDER BY lastName, firstName

Merging Data from Multiple Tables: Joining (Cont.)

firstName lastName isbn firstName lastName isbn Harvey Deitel 0130895601 Harvey Deitel 0130284173

Harvey Deitel 0130284181 Harvey Deitel 0130829293 Harvey Deitel 0134569555 Paul Deitel 0130852473

Harvey Deitel 0130829277 Paul Deitel 0138993947 Harvey Deitel 0130852473 Paul Deitel 0130125075 Harvey Deitel 0138993947 Paul Deitel 0130856118 Harvey Deitel 0130125075 Paul Deitel 0130161438 Harvey Deitel 0130856118 Paul Deitel 013028419x Harvey Deitel 0130161438 Paul Deitel 0139163050 Harvey Deitel 013028419x Paul Deitel 0135289106 Harvey Deitel 0139163050 Paul Deitel 0130895717 Harvey Deitel 0135289106 Paul Deitel 0132261197 Harvey Deitel 0130895717 Paul Deitel 0130895725 Harvey Deitel 0132261197 Tem Nieto 0130284181 Harvey Deitel 0130895725 Tem Nieto 0130284173 Paul Deitel 0130895601 Tem Nieto 0130829293 Paul Deitel 0130284181 Tem Nieto 0134569555 Paul Deitel 0130284173 Tem Nieto 0130856118 Paul Deitel 0130829293 Tem Nieto 0130161438 Paul Deitel 0134569555 Tem Nieto 013028419x Paul Deitel 0130829277 Sean Santry 0130895601 Fig. 8.21 Authors and the ISBN numbers for the books they have written in

ascending order by lastName and firstName.

INSERT INTO Statement

• Insert a new record into a table– INSERT INTO tableName

( fieldName1, … , fieldNameN ) VALUES ( value1, … , valueN )

•INSERT INTO authors ( firstName, lastName )

VALUES ( ‘Sue’, ‘Smith’ )


2 Paul Deitel 3 Tem Nieto 4 Sean Santry 5 Sue Smith Fig. 8.22 Table Authors after an INSERT INTO operation to add a record.

UPDATE Statement

• Modify data in a table– UPDATE tableName SET fieldName1 = value1, … , fieldNameN

= valueN WHERE criteria

• UPDATE authors

SET lastName = ‘Jones’ WHERE lastName = ‘Smith’ AND firstName = ‘Sue’


2 Paul Deitel 3 Tem Nieto 4 Sean Santry 5 Sue Jones Fig. 8.23 Table authors after an UPDATE operation to change a record.

DELETE FROM Statement

• Remove data from a table– DELETE FROM tableName WHERE

criteria •DELETE FROM authors

WHERE lastName = ‘Jones’ AND firstName = ‘Sue’


2 Paul Deitel 3 Tem Nieto 4 Sean Santry Fig. 8.24 Table authors after a DELETE operation to remove a record.

Documents

Web Application Deployment & JDBC CSC 667, Spring 2004 Dr. Ilmi Yoon