Web Application Deployment & JDBC CSC 667, Spring 2007 Dr. Ilmi Yoon

Web Application Web Application Deployment & JDBCDeployment & JDBC

Web Application Web Application Deployment & JDBCDeployment & JDBC

CSC 667, Spring 2007CSC 667, Spring 2007

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://tomcat.apache.org/tomcat-5.5-doc/appdev/index.html

• 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

Installation & Setup

• You may avoid these steps by installing ant & eclipse

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

servlet.jar, jasper.jar) or J2EE.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

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

JSP Tag Library

• In JavaServer Pages technology, actions are elements that can create and access programming language objects and affect the output stream. The JSP specification defines 6 standard actions that must be provided by any compliant JSP implementation.

• In addition to the standard actions, JSP v1.1 technology supports the development of reusable modules called custom actions. A custom action is invoked by using a custom tag in a JSP page. A tag library is a collection of custom tags.

• Before the availability of custom actions, JavaBeans components in conjunction with scriplets were the main mechanism for performing such processing. The disadvantage of using this approach is that it makes JSP pages more complex and difficult to maintain.

• Custom actions alleviate this problem by bringing the benefits of another level of componentization to JSP pages.

What JSP Tags can do?

• They can be customized via attributes passed from the calling page.

• They have access to all the objects available to JSP pages.

• They can modify the response generated by the calling page.

• They can communicate with each other. You can create and initialize a JavaBeans component, create a variable that refers to that bean in one tag, and then use the bean in another tag.

• They can be nested within one another, allowing for complex interactions within a JSP page.

JSP demo

• JSP 1.2 tags – JSTL (JSP Standard Tag Libraries)

• JSP 2.0 tags – JSTL like Tags• Types of Tags

– Simple Tags – Tags With Attributes – Tags With a Body

• Usages of Tags– Choosing Between Passing Information as

Attributes or Body – Tags That Define Scripting Variables – Cooperating Tags

Types of Tags

– Simple Tags • <tlt:greeting />

– Tags With Attributes• <tlt:greeting date="<%= today %>" />

– Tags With a Body • <tlt:greeting> <%= today %> </tlt:greeting>

– Usages of tags• Tags That Define Scripting Variables

– <tlt:lookup id="tx" type="UserTransaction" name="java:comp/UserTransaction" /> <% tx.begin(); %>

• Cooperating Tags – <tlt:tag1 id="obj1" attr2="value" /> <tlt:tag2

name="obj1" /> – <tlt:outerTag> <tlt:innerTag /> </tlt:outerTag>

Defining Tags

• Develop a tag handler and helper classes for the tag

• Declare the tag in a tag library descriptor (.tld)

<taglib> <tlibversion> - The tag library's version <jspversion> - The JSP specification version the tag library depends on <shortname> - A simple default name that could be used by a JSP page authoring tool to create names with a mnemonic value; for example, shortname may be used as the preferred prefix value in taglib directives and/or to create prefixes for IDs. <uri> - A URI that uniquely identifies the tag library <info> - Descriptive information about the tag library <tag>

<tagclass>classname</tagclass> … </tag> ... </taglib>

How is a Tag Handler Invoked?

• ATag t = new ATag();• t.setPageContext(...); • t.setParent(...);• t.setAttribute1(value1);• t.setAttribute2(value2);• t.doStartTag();

– out = pageContext.pushBody();– t.setBodyContent(out); // perform any initialization

needed after body content is set– t.doInitBody(); – t.doAfterBody();

• t.doEndTag(); – t.pageContext.popBody();

• t.release();

What methods need to be implemented?

Tag Handler Type

Methods

Simple doStartTag, doEndTag, release

Attributes doStartTag, doEndTag, set/getAttribute1...N

Body, no interaction

doStartTag, doEndTag, release

Body, interaction

doStartTag, doEndTag, release, doInitBody, doAfterBody

Simple Tags

• <tlt:simple /> public SimpleTag extends Tag Support {

public int doStartTag() throws JspException { try { pageContext.getOut().print("Hello."); } catch (Exception ex) {

throw new JspTagException("SimpleTag: " + e.getMessage()); }

return SKIP_BODY; }

public int doEndTag() { return EVAL_PAGE; }

}

TLD bodycontent Element Tags without bodies must declare that their body content is empty:

<tag> ... <bodycontent>empty</bodycontent>

</tag>

Tags with Attributes

• <tlt:twa attr1="value1"> Tag Handler should have

private AttributeClass attr1; setAttr1(AttributeClass ac) { ... } AttributeClass getAttr1() { ... }

TLD attribute Element <tag> ...

<attribute> <name>attr1</name> <required>true|false|yes|no</required>

<rtexprvalue>true|false|yes|no</rtexprvalue>

</attribute> </tag>

public class TwaTEI extends TagExtraInfo { public boolean isValid(Tagdata data) {

Object o = data.getAttribute("attr1"); ….return true;

}}

Tags with a Body

• If the body of the tag needs to be evaluated, the doStartTag method needs to return EVAL_BODY_TAG; otherwise it should return SKIP_BODY.

public class QueryTag extends BodyTagSupport { public int doAfterBody() throws JspTagException {

BodyContent bc = getBodyContent(); // get the bc as string String query = bc.getString(); // clean up bc.clearBody(); try { Statement stmt = connection.createStatement();

result = stmt.executeQuery(query); } catch (SQLException e) {

throw new JspTagException("QueryTag: " + e.getMessage()); }

return SKIP_BODY; }

}

JSTL-like Tags with JSP 2.0

• JSP 2.0 has two APIs, called Classic Tags API and Simple Tags API

• Extend SimpleTagSupport or one of its subclasses. The VarTagSupport, IfTag, and WhileTag classes

• http://www.oracle.com/technology/pub/articles/andrei_jsptags.html

• You are strongly encouraged to use as many tag libraries as possible in your term project.

• For easier grading, please demonstrate your tags during term project presentation.

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

Points to remember

• JDBC Driver – Load the proper driver• DB connection• Statement • Executing the statements• ResultSet • Close – close connection Or

connectionPool• PreparedStatement

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

Prepared Statement• Sometimes prepared statement is more convenient and

more efficient for sending SQL statements to the database.

• When to use PreparedStatement– When you want to execute a Statement object many times, it will normally reduce execution time to use a PreparedStatement object instead

• The main feature of a PreparedStatement object is that unlike a Statement object, it is given an SQL statement when it is created. The advantage to this is that in most cases, this SQL statement will be sent to the DBMS right away, where it will be compiled. As a result, the PreparedStatement object contains not just an SQL statement, but an SQL statement that has been precompiled.

• This means that when the PreparedStatement is executed, the DBMS can just run the PreparedStatement's SQL statement without having to compile it first.

PreparedStatement example

try{String _querySelect = “SELECT * FROM MOVIE WHERE title like ?”;

preStatement = connection.prepareStatement(_querySelect, ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_UPDATABLE );

}

Prepared Statement Example

• https://www.sdn.sap.com/irj/sdn/weblogs?blog=/pub/wlg/1938

Connection connection = DriverManager.getConnection("jdbc:sapdb://" + Server + "/" + Database, User, Password);

// Preparing the query to be executedpreStatement = connection.prepareStatement(

"insert into addimage values(?,?,?)"); // Setting the actual values in the querypreStatement.setString(1,fileId);preStatement.setString(2,fileDes);

// A file reader to get the contents of imageFileInputStream fi=new FileInputStream(fileName);byte[] Img= new byte[fi.available()+1];fi.read(Img);preStatement.setBytes(3,Img);

// Executing the SQL QuerypreStatement.execute();System.out.println("Image Successfully inserted into MaxDB!");

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

import util.MurachPool;

public class EmailServlet extends HttpServlet{

private MurachPool connectionPool;

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

public void destroy() { connectionPool.destroy(); } 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);

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 2007 Dr. Ilmi Yoon