Creation of a Java Bean And How it is Used in Java Server Pages

Here you will see how to create a Java bean and how it is used in Java Server Pages (JSP)



Java bean: It is a development component for performing a task in an application. Any ordinary java class with a set of variables and methods can be called as javabean. The methods present in a java bean must follow a naming convention. A java bean can be used in a web application to store the state of the users.

Creation process of a java bean:

  1. Create a class in a package as the bean class.
  2. Provide the required variables as the properties.
  3. Provide setter and getter methods for each of the variables.
  4. Store the package folder inside a classes folder.
  5. Compile the file as ordinary java file.

Store the following bean file in (E:\Servlet\WEB-INF\classes\pack1)

Example:

package pack1;
public class mybean
{
  private String name,pass;
  public void setName(String n)
   {
      name=n;
    }
     public void setPass(String p)
   {
      pass=p;
    }
  public String getName()
    {
     return name;
      }
    public String getPass()
    {
     return pass;
      }
  }

Compile of bean:- javac mybean.java

JavaBean

How to use this bean in JSP
  1. Use <jsp:useBean>; this tag creates an instance of the javabean in a JSP.

    Attribute

    Class- this contains name of the bean class with its package.
    Id-this contains name of the bean object.
    Scope-this is an optional attribute. This can contain a value such as page/request/session/application.
     
  2. Use <jsp:setProperty>; this tag calls setter methods of the bean.

    Attribute

    Name-this contains name of the bean object.
    Property-this contains name of the property whose setter method required to be called.
    Value-this contains value of the property to be assigned.
     
  3. Use <jsp:getProperty>; this tag can be used to call getter methods of the bean and to print the return value into the response.

    Attribute

    Name-this contains name of the bean object.
    Property-this contains name of the property whose getter method required to be called.

Program beantest.jsp

Save the following beantest.jsp file in your context folder (E:\Servlet)

<html>
<body bgcolor="yellow">
<p> <h3><center>Please enter your user name and
password</center></h3></p>
<form>
<center>username</center>
<center><input type ='text' name ="t1"></center>
<center>Password</center>
<center><input type ='password' name ="p1"></center>
<center><input type ='submit' value="submit" ></center>
</form>
<jsp:useBean class="pack1.mybean" id="mb1" />
<%
String s1=request.getParameter("t1") ;
String s2=request.getParameter("p1") ;
if(s1!= null){ %>
<jsp:setProperty name="mb1" property="name" value="<%= s1 %>" />
<jsp:setProperty name="mb1" property="pass" value="<%= s2 %>" />
<h2>Name is :<jsp:getProperty name="mb1" property="name" /></h2>
<h2>Password is :<jsp:getProperty name="mb1" property="pass" /></h2>
<% } %>
</body>
</html>

Running the file

http://localhost:8082/javaservlet/beantest.jsp

JavaBean