Examples of Using Servlets and JSP Representation and Management of Data on the Internet

Examples of Using Servlets and JSP

Representation and Management of Data on the Internet

Working with Xaln

Combining Servlets and XSL

Working With XSL

• Add to the CLASSPATH:– setenv CLASSPATH ${CLASSPATH}:/usr/local/java/apache/xerces/xerces.jar

– setenv CLASSPATH ${CLASSPATH}:/usr/local/java/apache/xalan/xalan.jar

You can download from the Web newer versions ofXalan and Xerces

You can download from the Web newer versions ofXalan and Xerces

<?xml version="1.0"?><ROWSET><ROW><Subject>Java</Subject><Title>Hello Java</Title><Price>19$</Price></ROW><ROW><Subject>XML</Subject><Title>XML for Beginners</Title><Price>12$</Price></ROW>

<ROW><Subject>XSL</Subject><Title>XSL in a Nut Shell</Title><Price>34$</Price></ROW><ROW><Subject>JSP</Subject><Title>Introduction to JSP</Title><Price>17$</Price></ROW><ROW><Subject>JavaScript</Subject><Title>A Path to JavaScript</Title><Price>33$</Price></ROW></ROWSET>

doc.xml

<?xml version="1.0"?><xsl:stylesheet version="1.0"

xmlns:xsl="http://www.w3.org/1999/XSL/Transform"><xsl:output method="html" /><xsl:template match="/"><HTML><HEAD><TITLE>A dbi Example</TITLE></HEAD><BODY bgcolor="F0F0F0" text="550000"> <CENTER><H1>Books List</H1></CENTER> <TABLE BORDER="2" ALIGN="center"> <TR><TH></TH>

<xsl:for-each select="ROWSET/ROW[1]/*"><TH><xsl:value-of select="name()" /></TH>

</xsl:for-each> </TR> <xsl:apply-templates select="ROWSET" /> </TABLE></BODY></HTML></xsl:template>

<xsl:template match="ROW"> <TR><TD><xsl:number /></TD>

<xsl:for-each select="*"> <TD><xsl:value-of select="." /> </TD></xsl:for-each>

</TR></xsl:template>

</xsl:stylesheet>

doc.xsl

TransformServlet

import java.io.*;import javax.servlet.*;import javax.servlet.http.*;import org.apache.xalan.xslt.*;

public class TransformServlet extends HttpServlet { // Respond to HTTP GET requests from browsers. public void doGet (HttpServletRequest request,

HttpServletResponse response) throws ServletException, IOException {

// Set content type for HTML.response.setContentType("text/html; charset=UTF-8");// Output goes to the response PrintWriter.PrintWriter out = response.getWriter();

try{ XSLTProcessor processor =

XSLTProcessorFactory.getProcessor(); // Get the XML input document and the stylesheet, // both in the servlet engine document directory. XSLTInputSource xmlSource =

new XSLTInputSource(new java.net.URL("http://www.cs.huji.ac.il/~yarok/doc.xml").openStream());

XSLTInputSource xslSource = new XSLTInputSource(new java.net.URL("http://www.cs.huji.ac.il/~yarok/doc.xsl").openStream());

// Generate the result. XSLTResultTarget target =

new XSLTResultTarget(out);

// Creating the output processor.process(xmlSource, xslSource, target);}

// If an Exception occurs, //return the error to the client.catch (Exception e) {

out.write(e.getMessage());e.printStackTrace(out);

}// Close the PrintWriter.out.close();

} }

Creating Results to a File

• A More Simple Example (not a servlet)– Gets input from files where file names given as

parameters– Write output to a file whose name given as a

parameter

import org.apache.xalan.xslt.XSLTProcessorFactory;import org.apache.xalan.xslt.XSLTInputSource;import org.apache.xalan.xslt.XSLTResultTarget;import org.apache.xalan.xslt.XSLTProcessor;

/** * Simple sample code to show how * to run the XSL processor * from the API. */public class TransformExample{ public static void main(String[] args)

throws java.io.IOException, java.net.MalformedURLException, org.xml.sax.SAXException

{

{// Have the XSLTProcessorFactory // obtain a interface to a// new XSLTProcessor object.XSLTProcessor processor =

XSLTProcessorFactory.getProcessor();

processor.process(new XSLTInputSource(args[0]), new XSLTInputSource(args[1]), new XSLTResultTarget(args[2])); }}

Using Beans in JSP

http://mangal:9999/dbi/jsp/dbconnect.jsp?login=yarok

http://mangal:9999/dbi/jsp/dbinsert.jsp?login=yarok

http://mangal:9999/dbi/jsp/dbinsertmore.jsp?login=yarok

The Bean Object

• The bean object is under the directory <tomcat_home>/lib/dbi

• The bean belongs to the package “dbi”

package dbi;

import java.sql.*; import java.io.*;

/** * Example of using Java Beans in JSP pages */

public class DBBean { String login = null; String url = "jdbc:oracle:thin:"+ login + "/" +

login + "@sol4:1521:stud"; String driver = "oracle.jdbc.driver.OracleDriver"; private Connection connection;

public DBBean() { super(); } public String getLogin() {

return login; } public void setLogin(String login) {

this.login = login; }

public boolean connect()

throws ClassNotFoundException,SQLException { Class.forName(driver); connection = DriverManager.getConnection(url);

return true; } public void close() throws SQLException {

connection.close(); }

public ResultSet poseQuery(String sql)

throws SQLException {

Statement s = connection.createStatement(); ResultSet rs = s.executeQuery(sql); return rs; } public int applyUpdate(String sql)

throws SQLException {

Statement s = connection.createStatement(); int r = s.executeUpdate(sql); return r; } }

The JSP Pages

• There are three JSP pages

• The first page opens the connection

• The third page closes the connection

• All three pages using the same bean

First Page

<HTML> <HEAD><TITLE>Example of using beans in a JSP – Connect</TITLE></HEAD> <BODY>

<%@ page language="Java" import="java.sql.*" %>

<jsp:useBean id="db" scope="session" class="dbi.DBBean" />

<jsp:setProperty name="db" property="login" param="login" />

<%! ResultSet rs = null ; ResultSetMetaData rsmd = null ; int numColumns ; int i; %>

<center> <h2> Created the Table </h2> (in the database of the user <jsp:getProperty name="db" property="login"/>)<hr> <br><br> <font color="blue" size="4"><table border=1>

<% db.connect();

try { db.applyUpdate("DROP TABLE test");} catch (Exception e) {}

try { i = db.applyUpdate("CREATE TABLE test

(name varchar2(10), id number(6))"); rs = db.poseQuery("SELECT * FROM test"); } catch(SQLException e) { throw new ServletException

("Error in the query", e); }

rsmd = rs.getMetaData(); numColumns = rsmd.getColumnCount(); %>

<TR><% for (int column=1; column <= numColumns; column++) { %> <TD><%= rsmd.getColumnName(column) %> </TD> <% } %>

</TR>

<% while(rs.next()) { %> <TR><TD><%= rs.getString("name") %></TD> <TD><%= rs.getString("id") %></TD></TR> <% } %> </table> </font>

<P><font color="red" size="6">Created the Tables</font> <P>

<a href="dbinsert.jsp?login=<jsp:getProperty name="db" property="login"/>">Next</a></body>

</HTML>

Second Page

<HTML> <HEAD><TITLE>Example of using beans in a JSP – Insert</TITLE></HEAD> <BODY>





<center> <h2> Inserting Two Rows </h2> (in the database of the user <jsp:getProperty name="db" property="login"/>)<hr> <br><br> <font color="blue" size="4"><table border=1>

<%try{ i = db.applyUpdate(

"INSERT INTO test VALUES ('aaa', 123)"); i = db.applyUpdate(

"INSERT INTO test VALUES ('bbb', 456)"); rs = db.poseQuery("SELECT * FROM test"); } catch(SQLException e) { throw new ServletException




</TR>


<P><font color="red" size="6">After Insertion</font> <P>

<a href="dbinsertmore.jsp?login=<jsp:getProperty name="db" property="login"/>">Next</a></body>

</HTML>

Third Page

<HTML> <HEAD><TITLE>Example of using beans in a JSP – Insert</TITLE></HEAD> <BODY>





<center> <h2> Inserting Two More Rows </h2> (in the database of the user <jsp:getProperty name="db" property="login"/>)<hr> <br><br> <font color="blue" size="4"><table border=1>

<%try{ i = db.applyUpdate(

"INSERT INTO test VALUES (‘ccc', 789)"); i = db.applyUpdate(

"INSERT INTO test VALUES (‘ddd', 911)"); rs = db.poseQuery("SELECT * FROM test"); } catch(SQLException e) { throw new ServletException




</TR>


<%

db.close();

%> <BR><font color="red" size="6">Done</font> <P>

</body>

</HTML>

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Examples of Using Servlets and JSP Representation and Management of Data on the Internet