Servlet控制器作用

package com.demo.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class AServlet extends HttpServlet {

	public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
		
		request.setAttribute("theRequestValue", 2014);
		
		request.getRequestDispatcher("/B?param=2013").forward(request, response);
		
//		response.sendRedirect("/Controller/B?param=2013");
		
//		response.sendRedirect("B?param=2013");
	}
}

package com.demo.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class BServlet extends HttpServlet {

	public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException{
		
		PrintWriter out=response.getWriter();
		
		String param=request.getParameter("param");
		
		Integer theRequestValue=(Integer) request.getAttribute("theRequestValue");
		
		out.print("param:"+param);
		
		out.print("<br/>");

		out.print("theRequestValue:"+theRequestValue);
		
		out.flush();
		
		out.close();
	}
}