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Implementing Bean with scriptlet in JSP

Example for implementing bean with scriptlet <% code %> in a JSP
page
We can use all of the JSP coding while using Java Beans in a JSP page. There
are three main kinds of JSP scripting elements in JSP.
- <%= expression %> is called Expression to evaluate
value in output
- <% somecode %> is called Scriptlet that
are inserted into serlet's "service" method
- <%! declaration %> is called JSP Declaration for
declaring objects of components.
JSP Scriptlets
If you want to do some coding of multiple lines or of single lines rather
than inserting a single expression then you can use JSP scriptlets in the
following way :
For example if you have to use "if-else" in your JSP page
you can use it like this:
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<%
if(condition) {
some statements..
}
else{
some statements..
}
%>
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In this way, JSP scriptlet lets you do java coding in a JSP page wherever
you want. Following example will describe you to use JSP Scriptlet in a JSP page
using Java Beans. In our example we have made a bean file which is making the
database connection in its constructor and after getting connection according to
getter and setter method it will insert values into database by insert()
method of this bean.
For inserting data into bean file we are using MySQL database and connecting
to the database "messagepaging" and table is "message"
and structure of this database table is given as below:
CREATE TABLE `message` (
`id` int(11) NOT NULL auto_increment,
`message` varchar(256) default NULL,
PRIMARY KEY (`id`)
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Bean file code for this example
bean is given as below:
bean.java
package myexample;
import java.io.*;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.ResultSet;
public class bean
{
private int msgid;
private String message;
private Connection connection=null;
private ResultSet rs = null;
private Statement st = null;
String connectionURL = "jdbc:mysql://192.168.10.59/messagepaging";
public bean()
{
try {
// Load the database driver
Class.forName("com.mysql.jdbc.Driver");
// Get a Connection to the database
connection = DriverManager.getConnection(connectionURL, "root", "root");
}
catch(Exception e){
System.out.println("Exception is ;"+e);
}
}
public void setmsgid(int msgid){
this.msgid = msgid;
}
public int getmsgid(){
return (this.msgid);
}
public void setmessage(String message){
this.message = message;
}
public String getmessage(){
return (this.message);
}
public void insert(){
try{
String sql = "insert into message(id,message)
values('"+msgid+"','"+message+"')";
Statement s = connection.createStatement();
s.executeUpdate (sql);
s.close ();
}
catch(Exception e){
System.out.println("Exception is ;"+e);
}
}
}
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This "bean.java" file has two properties "msgid"
and "message" which are having their setter and getter to set
and get properties values and these properties are being set in the JSP file
using following code
<jsp:useBean id="sample" class="myexample.bean" scope="page">
<jsp:setProperty name="sample" property="*"/>
</jsp:useBean> |
And by using scrpitlet in JSP we are calling insert method when the
form will be submit.
where "sample" is the id assigned for "bean.java"
in myexample package. Full JSP code for "jspBean.jsp" is given
as:
<%@ page language="Java" import="java.sql.*" %>
<html>
<head><title>Using Scriptlet to use Bean</title></head>
<body bgcolor="#ffccff">
<h1>Using JSP Scriptlet to use Bean</h1>
<form name="form1" method="POST">
<table border="0" width="35%">
<tr>
<td width="10%"><b>ID</b></td>
<td width="90%"><input type="text" name ="msgid"></td>
</tr>
<tr>
<td width="10%"><b>Message</b></td>
<td width="90%"><input type="text" name ="message"> </td>
</tr>
<tr>
<td width="100%" colspan="2" align="center"><p align="left">
<input type = "submit" value="Submit">
</td>
</tr>
</table>
<jsp:useBean id="sample" class="myexample.bean" scope="page">
<jsp:setProperty name="sample" property="*"/>
</jsp:useBean>
<!--Bean method called using JSP scriptlet -->
<% sample.insert();%>
</form>
</body>
</html>
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To run this example you can go through the following steps:
- Create and Save "bean.java".
- Compile and put class file into classes folder
- Create and save jspBean.jsp file and put this in a folder (e.g JSPexample
in our example)
- Start Tomcat Server and type the following URL in address bar
http://localhost:8080/JSPexample/jspBean.jsp
Output:

Download Sourcecode

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