JSP and JavaBean

In this tutorial, we will see how a JSP interacts with a JavaBean. This helps to easily program and flexibly manage data at the server side.

A JavaBean is just a standard Java class that:
- all properties are private (access by getters and setters)
- has a public no-argument constructor
- implements the java.io.Serializable interface
Let's create a JavaBean named student as following.
Open the jsplabs project created in previous tutorial.
Right-click on the src folder, select New→Package. Name it as person.bean.
Right-click on the person.bean package, select New→Class. Name it Student and click Finish.

Replace the existing codes by the following:

package person.bean;
 
public class Student implements java.io.Serializable{
	private String firstName = null;
	private String lastName = null;	
	private int age = 0;
 
	public Student(){}
 
	public String getFirstName(){
	      return firstName;
	   }
	   public String getLastName(){
	      return lastName;
	   }
	   public int getAge(){
	      return age;
	   }
	   public void setFirstName(String firstName){
	      this.firstName = firstName;
	   }
	   public void setLastName(String lastName){
	      this.lastName = lastName;
	   }
	   public void setAge(int age){
	      this.age = age;
	   }
}

The class Student is a JavaBean. Now we creates a JSP to interact with this bean.
Right click on the WebContent folder, select New→JSP file.
Name it bean.jsp and click Finish.
JSP use tags: useBean to instantiate a bean, getProperty and setProperty to get and set bean's properties.

For example, insert the following codes between the <body> tags.

<jsp:useBean id="student" 
                    class="person.bean.Student"> 
   <jsp:setProperty name="student" property="firstName"
                    value="Zara"/>
   <jsp:setProperty name="student" property="lastName" 
                    value="Ali"/>
   <jsp:setProperty name="student" property="age" 
                    value="10"/>
</jsp:useBean>
 
<p>Student First Name: 
   <jsp:getProperty name="student" property="firstName"/>
</p>
<p>Student Last Name: 
   <jsp:getProperty name="student" property="lastName"/>
</p>
<p>Student Age: 
   <jsp:getProperty name="student" property="age"/>
</p>

Save the file.
Run it by right clicking on it then selecting Run As→Run on Server. Select Finish.
The student's name and age will be presented on your web browser at the URL: http://localhost:8080/jsplabs/bean.jsp

Exercises

Add a function getFullName() in the JavaBean Student. Then modify the bean.jsp file to show the full name of the current student.
Modify the bean.jsp file to set and get bean properties (firstname, lastname, age) based on request's parameters.

teaching_assistant/servlet-jsp/jsp-bean.txt · Last modified: 2013/07/08 08:44 (external edit)

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