...
Code to retrieve the image from derby database
- Create a jsp page with the name ImageDownload.jsp.
- Append the jsp with the following code
| Code Block |
|---|
| title | ImageDownload.jsp |
|---|
| borderStyle | solid |
|---|
|
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Download Image</title>
</head>
<body>
<h2>Name a Image to download</h2>
<form action="/WebJDBC/ImageDownload">
<table>
<tr>
<td>
Name of the Image
</td>
<td>
<Input type="text" name="ImageName">
</td>
</tr>
<tr>
<td>
<Input type="submit" value="submit">
</td>
<tr>
</table>
</form>
</body>
</html>
|
As can be seen from <form action="/WebJDBC/ImageDownload"> this jsp requests ImageDownload servlet when the form is submitted. - Create a new servlet ImageDownload.java and add the following code
| Code Block |
|---|
| title | ImageDownload.java |
|---|
| borderStyle | solid |
|---|
|
package jdbc;
import java.io.IOException;
import java.io.OutputStream;
import java.sql.Blob;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import javax.annotation.Resource;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.sql.DataSource;
public class ImageDownload extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
@Resource(name = "jdbc/userds")
private DataSource ds;
static final long serialVersionUID = 1L;
public ImageDownload() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doProcess(request, response);
}
protected void doProcess(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
Connection dbconnect = null;
ResultSet rs = null;
PreparedStatement stmnt = null;
try {
dbconnect = ds.getConnection();
String s=request.getParameter("ImageName");
stmnt = dbconnect.prepareStatement("SELECT PIC FROM PICTURES WHERE NAME=?");
stmnt.setString(1, s);
rs = stmnt.executeQuery();
if (rs.next()) {
// Get as a BLOB
Blob aBlob = rs.getBlob(1);
byte[] b = new byte[4096];
java.io.InputStream ip = aBlob.getBinaryStream();
OutputStream out = null;
int c = 0;
out = response.getOutputStream();
response.setContentType("image/jpeg");
while (c != -1) {
c = ip.read(b);
out.write(b);
out.flush();
}
ip.close();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try{
dbconnect.close();
stmnt.close();
rs.close();
}catch(SQLException e){
e.printStackTrace();
}
}
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doProcess(request, response);
}
}
|
This completes the code for Image download.
Modifying deployment plan
Next step is to modify the deployment plan that is geronimo-web.xml. We need to add the dependency element for JDBC resource. Also we need to add a resource reference element for the userds datasource.
| Code Block |
|---|
| title | geronimo-web.xml |
|---|
| borderStyle | solid |
|---|
|
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://geronimo.apache.org/xml/ns/j2ee/web-1.1" xmlns:nam="http://geronimo.apache.org/xml/ns/naming-1.1" xmlns:sec="http://geronimo.apache.org/xml/ns/security-1.1" xmlns:sys="http://geronimo.apache.org/xml/ns/deployment-1.1">
<sys:environment>
<sys:moduleId>
<sys:groupId>default</sys:groupId>
<sys:artifactId>WebJDBC</sys:artifactId>
<sys:version>1.0</sys:version>
<sys:type>car</sys:type>
</sys:moduleId>
<sys:dependencies>
<sys:dependency>
<sys:groupId>console.dbpool</sys:groupId>
<sys:artifactId>jdbc%2Fuserds</sys:artifactId>
</sys:dependency>
</sys:dependencies>
</sys:environment>
<context-root>/WebJDBC</context-root>
<nam:resource-ref>
<nam:ref-name>jdbc/userds</nam:ref-name>
<nam:pattern>
<nam:groupId>console.dbpool</nam:groupId>
<nam:artifactId>jdbc%2Fuserds</nam:artifactId>
<nam:name>jdbc/userds</nam:name>
</nam:pattern>
</nam:resource-ref>
</web-app>
|
Deploy and Run
