Hi. If you are using a web app to get data from a DB and then showing the data in an HTML form, use MVC Model 2 design
pattern. You can read up about this on the web. Here is a simple example using a
Servlet to query teh DB and populate an ArrayList filled with movie
java beans. The (Array)List is then added to the request as an attribute and then forwarded to a JSP. The jsp used JSTL to access the (Array)List and display the data. I showed it using EL and getProperty to access the data. I hope this helps. Let me know what you think.
Servlet: QueryServlet.java
/*
* Created on Nov 23, 2004
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package com.db.servlets;
import com.db.beans.*;
import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* @author none
*
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class QueryServlet extends HttpServlet {
/* (non-Javadoc)
* @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
Class.forName("oracle.jdbc.driver.OracleDriver");
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
List actionMovies = populateMovieList("Action");
List comedyMovies = populateMovieList("Comedy");
request.setAttribute("ActionMovies", actionMovies);
request.setAttribute("ComedyMovies", comedyMovies);
RequestDispatcher rd = request.getRequestDispatcher("ViewMovies.jsp");
rd.forward(request, response);
}
/* (non-Javadoc)
* @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)
*/
protected void doPost(HttpServletRequest arg0, HttpServletResponse arg1)
throws ServletException, IOException {
doGet(arg0, arg1);
}
private List populateMovieList(
String movieType) {
Connection conn = null;
ArrayList movies = new ArrayList();
try {
conn = DriverManager.getConnection("jdbc
racle:thin:@<machine name>:<port>:<db _sid>", "username", "password");
Statement stmt = conn.createStatement();
ResultSet rset = stmt.executeQuery("Select id, title, description from videos where section = '" + movieType + "' order by title");
Movie movie = null;
while (rset.next()) {
movie = new Movie();
movie.setId(rset.getInt(1));
movie.setTitle(rset.getString(2));
movie.setDesc(rset.getString(3));
System.out.println("Adding " + movie.getTitle() + " to movie list");
movies.add(movie);
}
rset.close();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} finally {
try {
conn.close();
} catch (Exception exp) {}
}
return movies;
}
}
------------------------------------------------------------
JSP: ViewMovies.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jstl/core_rt" %>
<html>
<body>
<center>
<b><h2>Movie List</h2></b>
<p>
<table border=2 width="45%">
<tr>
<td colspan="2" align="center"><b>Comedy Movies</b></td>
</tr>
<tr>
<td><b>Title</b></td>
<td><b>Description</b></td>
</tr>
<c:forEach var="comedy" items="${ComedyMovies}" >
<tr>
<td><jsp:getProperty name="comedy" property="title" /></td>
<td><jsp:getProperty name="comedy" property="desc" /></td>
</tr>
</c:forEach>
</table>
<p>
<table border="2" width="45%">
<tr>
<td colspan="2" align="center"><b>Action Movies</b></td>
</tr>
<tr>
<td><b>Title</b></td>
<td><b>Description</b></td>
</tr>
<c:forEach var="action" items="${ActionMovies}" >
<tr>
<td>${action["title"]}</td>
<td>${action["desc"]}</td>
</tr>
</c:forEach>
</table>
</center>
</body>
</html>
------------------------------------------------------------
file: web.xml
?xml version="1.0" encoding="ISO-8859-1"?>
<web-app
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" version="2.4"
>
<display-name>
Test DB</display-name>
<session-config>
<session-timeout>1</session-timeout>
</session-config>
<!-- The Usual Welcome File List -->
<welcome-file-list>
<welcome-file>Welcome.jsp</welcome-file>
</welcome-file-list>
<servlet>
<servlet-name>QueryDBServlet</servlet-name>
<servlet-class>com.db.servlets.QueryServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>QueryDBServlet</servlet-name>
<url-pattern>/QueryDB.do</url-pattern>
</servlet-mapping>
</web-app>
-------------------------------------------------------
JavaBean: Movie.java
/*
* Created on Nov 23, 2004
*
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
*/
package com.db.beans;
/**
* @author none
* TODO To change the template for this generated type comment go to
* Window - Preferences - Java - Code Style - Code Templates
*/
public class Movie {
private int id;
private String title;
private String desc;
/**
* @return Returns the desc.
*/
public String getDesc() {
return desc;
}
/**
* @param desc The desc to set.
*/
public void setDesc(String desc) {
this.desc = desc;
}
/**
* @return Returns the id.
*/
public int getId() {
return id;
}
/**
* @param id The id to set.
*/
public void setId(int id) {
this.id = id;
}
/**
* @return Returns the title.
*/
public String getTitle() {
return title;
}
/**
* @param title The title to set.
*/
public void setTitle(String title) {
this.title = title;
}
}
----------------
