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Web Application Deployment & JDBC CSC 667, Spring 2004 Dr. 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/2001/0 3/15/tomcat.html • http://www.onjava.com/pub/a/onjava/2001/0 4/19/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/~csc667/0424/667_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 document. files contained this Thispublic directory is whereNo servlet and utilityinclasses directory can be served directly to a client. are located. /onjava/WEB-INF/classes /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/WEBINF/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/WEBINF/classes (3.1) • Invoking the servlets – http://host:port/servlet/Packagename.servetN ame 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 App</display-name> <sessiontimeout>30</session-timeout> <servlet> <servlet-name>TestServlet</servlet-name> <servletclass>com.onjava.TestServlet</servlet-class> <load-on-startup>1</load-on-startup> <initparam> <param-name>name</param-name> <param-value>value</param-value> </initparam> </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 Create Connection at Init() 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); } 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 This section is self-study section Relational-Database Model Row /Rec ord Number Name Department Salary Location 23603 Jones 413 1100 New Jersey 24568 Kerwin 413 2000 New Jersey 34589 Larson 642 1800 Los Ang ele s 35761 M yers 611 1400 Orla nd o 47132 Neum ann 413 9000 New Jersey 78321 Step he ns 611 8500 Orla nd o Prima ry key Column/ Fie ld 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 authorID Desc rip tion 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 ta b le fro m books. authorID 1 firstName Harvey lastName Deitel 2 Paul Deitel 3 Tem Nieto 4 Sean Santry Fig. 8.4 Da ta fro m the authors ta b le o f books. Relational Database Overview: The books Database (Cont.) Fie ld publisherID De sc rip tio n 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 ta b le fro m books. publisherID 1 publisherName Prentice Hall 2 Prentice Hall PTG Fig. 8.6 Da ta fro m the publishers ta b le o f books. Relational Database Overview: The books Database (Cont.) Fie ld authorID De sc rip tio n 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 ta b le fro m books. Relational Database Overview: The books Database authorID 1 isbn 0130895725 authorID 2 1 0132261197 2 1 0130895717 2 1 0135289106 2 1 0139163050 2 1 013028419x 2 1 0130161438 2 1 0130856118 2 1 0130125075 2 1 0138993947 2 1 0130852473 2 1 0130829277 2 1 0134569555 2 1 0130829293 3 1 0130284173 3 1 0130284181 3 1 0130895601 3 2 0130895725 3 2 0132261197 3 2 0130895717 3 2 0135289106 4 Fig. 8.8 Da ta fro m the authorISBN ta b le o f books. isbn 0139163050 013028419x 0130161438 0130856118 0130125075 0138993947 0130852473 0130829277 0134569555 0130829293 0130284173 0130284181 0130895601 013028419x 0130161438 0130856118 0134569555 0130829293 0130284173 0130284181 0130895601 Relational Database Overview: The books Database (Cont.) Fie ld isbn De sc rip tio n ISBN number of the book (a string). title editionNumber Title of the book (a string). Edition number of the book (an integer). copyright publisherID Copyright year of the book (a string). 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 ta b le fro m books. Relational Database Overview: The books Database (Cont.) authors authorID firstName lastName 1 authorISBN authorID isbn publishers publisherID publisherName 1 1 Fig. 8.11 Table relationships in books. titles isbn title editionNumber copyright publisherID imageFile price Structured Query Language (SQL) • SQL overview • SQL keywords SQL ke yw o rd SELECT De sc rip tio n 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 q ue ry ke yw o rd s. 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 1 2 3 4 Fig. 8.13 lastName Deitel Deitel Nieto Santry authorID a nd lastName fro m the authors ta b le . 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, lastName FROM authors WHERE lastName LIKE ‘D%’ authorID 1 2 Fig. 8.15 firstName Harvey lastName Deitel Paul Deitel Autho rs w ho se la st na m e sta rts w ith D fro m the authors ta b le . WHERE Clause (Cont.) •SELECT authorID, firstName, lastName FROM authors WHERE lastName LIKE ‘_i%’ authorID 3 firstName Tem lastName Nieto Fig. 8.16 The o nly a utho r fro m the authors ta b le w ho se la st na m e c o nta ins i a s the se c o nd le tte r. 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.) •SELECT authorID, firstName, lastName FROM authors ORDER BY lastName ASC authorID 2 1 3 4 Fig. 8.17 firstName Paul lastName Deitel Harvey Deitel Tem Nieto Sean Santry Autho rs fro m ta b le authors in a sc e nd ing o rd e r b y lastName. ORDER BY Clause (Cont.) •SELECT authorID, firstName, lastName FROM authors ORDER BY lastName DESC authorID 4 3 2 1 Fig. 8.18 firstName Sean lastName Santry Tem Nieto Paul Deitel Harvey Deitel Autho rs fro m ta b le authors in d e sc e nd ing o rd e r b y lastName. ORDER BY Clause (Cont.) •SELECT authorID, firstName, lastName FROM authors ORDER BY lastName, firstName authorID 1 firstName Harvey lastName Deitel 2 Paul Deitel 3 Tem Nieto 4 Sean Santry Fig. 8.19 Autho rs fro m ta b le authors in a sc e nd ing o rd e r b y lastName a nd b y firstName. ORDER BY Clause (Cont.) •SELECT isbn, title, editionNumber, copyright, price FROM titles WHERE title LIKE ‘%How to Program’ ORDER BY title ASC isbn 0130895601 0132261197 0130895725 0135289106 0130895717 0130161438 title edition- copyNumber right Advanced Java 2 Platform How to Program 1 2002 price 69.95 C How to Program 2 1994 49.95 C How to Program 3 2001 69.95 C++ How to Program 2 1998 49.95 C++ How to Program 3 2001 69.95 Internet and World Wide Web How to 1 2000 69.95 Program 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 1 2001 69.95 Program Fig. 8.20 Bo o ks fro m ta b le titles w ho se title e nd s w ith How to Program in a sc e nd ing o rd e r b y 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 Harvey lastName Deitel isbn 0130895601 firstName Harvey lastName Deitel isbn 0130284173 Harvey Harvey Deitel Deitel 0130284181 0134569555 Harvey Paul Deitel Deitel 0130829293 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 A utho rs a nd the ISBN num b e rs fo r the b o o ks the y ha ve w ritte n in a sc e nd ing o rd e r b y lastName a nd 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’ ) authorID 1 2 3 4 5 Fig. 8.22 firstName Harvey lastName Deitel Paul Deitel Tem Nieto Sean Santry Sue Smith Ta b le Authors a fte r a n INSERT INTO o p e ra tio n to a d d a re c o rd . 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’ authorID 1 2 3 4 5 Fig. 8.23 firstName Harvey lastName Deitel Paul Deitel Tem Nieto Sean Santry Sue Jones Ta b le authors a fte r a n UPDATE o p e ra tio n to c ha ng e a re c o rd . DELETE FROM Statement • Remove data from a table – DELETE FROM tableName WHERE criteria •DELETE FROM authors WHERE lastName = ‘Jones’ AND firstName = ‘Sue’ authorID 1 2 3 4 Fig. 8.24 firstName Harvey lastName Deitel Paul Deitel Tem Nieto Sean Santry Ta b le authors a fte r a DELETE o p e ra tio n to re m o ve a re c o rd .