Java: How to send values from Servlet to Servlet

How to send values from Servlet to Servlet

Set the value with request.setAttribute (java.lang.String name, java.lang.Object o) and retrieve the value with getAttribute (java.lang.String name).

sample

--Folder structure - webTest - Hoge.java - Test1.java - Test2.java - webTest2 - Moge.java - WebContent - test.jsp --Run Test1.java and it will work

Test1.java

package webTest;


import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import webTest2.Moge;

/**
 * Servlet implementation class Test1
 */
@WebServlet("/Test1")
public class Test1 extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Test1() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		//response.getWriter().append("Served at: ").append(request.getContextPath());

		Moge m = new Moge(1,2);

		request.setAttribute("bean", m);

		//Transition to JSP
		RequestDispatcher disp = request.getRequestDispatcher("/Test2");
		disp.forward(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

Test2.java

package webTest;


import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import webTest2.Moge;

/**
 * Servlet implementation class Test1
 */
@WebServlet("/Test2")
public class Test2 extends HttpServlet {
	private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public Test2() {
        super();
        // TODO Auto-generated constructor stub
    }

	/**
	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		//response.getWriter().append("Served at: ").append(request.getContextPath());

		Moge m = (Moge)request.getAttribute("bean");
		Hoge h = new Hoge(3,4, m);

		request.setAttribute("bean", h);

		//Transition to JSP
		RequestDispatcher disp = request.getRequestDispatcher("/test.jsp");
		disp.forward(request, response);
	}

	/**
	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doGet(request, response);
	}

}

Moge.java

package webTest2;

public class Moge {
	private int a;
	private int b;

	public Moge(){

	}

	public Moge(int a, int b){
		this.a = a;
		this.b = b;
	}

	public int getA() {
		return a;
	}

	public void setA(int a) {
		this.a = a;
	}

	public int getB() {
		return b;
	}

	public void setB(int b) {
		this.b = b;
	}

	@Override
	public String toString() {
		return "Hoge [a=" + a + ", b=" + b + "]";
	}
}

Hoge.java

package webTest;

import webTest2.Moge;

public class Hoge {
	private int a;
	private int b;
	private Moge m;

	public Moge getM() {
		return m;
	}

	public void setM(Moge m) {
		this.m = m;
	}

	public Hoge(){

	}

	public Hoge(int a, int b, Moge m) {
		super();
		this.a = a;
		this.b = b;
		this.m = m;
	}

	public int getA() {
		return a;
	}

	public void setA(int a) {
		this.a = a;
	}

	public int getB() {
		return b;
	}

	public void setB(int b) {
		this.b = b;
	}

	@Override
	public String toString() {
		return "Hoge [a=" + a + ", b=" + b + ", m=" + m + "]";
	}


}

test.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>

<jsp:useBean
  		id="bean"
  		class="webTest.Hoge"
  		scope="request" />

<%@ page import="webTest2.Moge"%>

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>

	<%= bean.getM() %>
</body>
</html>