1、都是在一个请求中跨越多个Servlet
2、多个Servlet在一个请求中，他们共享request对象。就是在AServle中setAttribute（）保存数据在BServlet中由getAttribute（）取出数据
3、在AServlet转发到BServlet，那么整个请求都是由BServlet来完成，AServlet不再插手
4、AServlet 包含BServlet，那么两个Servlet共同完成请求
5、请求转发和请求包含都需要使用一个对象RequestDispatcher。
AServlet.java
package cn.edu.aynu.rjxy.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class AServlet extends HttpServlet {
/*
* 请求转发
* */
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//设置响应头
response.setContentType("text/html;charset=utf-8");
response.getWriter().print("AServlet...");
request.setAttribute("name", "张三");
//获得RequestDispatcher对象
RequestDispatcher rd = request.getRequestDispatcher("/BServlet");
//将request对象和response对象传递给BServlet
rd.forward(request, response);
}
}
BServlet.java
package cn.edu.aynu.rjxy.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 {
String name = (String) request.getAttribute("name");
response.getWriter().print("BServlet为您服务...");
response.getWriter().print("name="+name);
}
}
CServlet.java
package cn.edu.aynu.rjxy.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class CServlet extends HttpServlet {
/*
* 请求包含
* */
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//设置响应头
response.setContentType("text/html;charset=utf-8");
response.getWriter().print("AServlet为您服务...");
RequestDispatcher rd = request.getRequestDispatcher("/DServlet");
rd.include(request, response);
}
}
DSevler.java
package cn.edu.aynu.rjxy.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 DServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.getWriter().print("DServlet为您服务...");
}
}
1、请求转发是一个请求，而重定向是两个请求
2、请求转发后浏览器地址栏不会发生变化重定向会发生变化
3、请求转发的目标只能在本项目中的资源，重定向的目标可以是其他应用
4、请求转发对Aservlet和Bservlet的请求方法是相同的，就是要么都是get，要么都是post。因为他们是同一个请求
5、请求转发可以在多个Servlet中共享request的数据，而重定向不行。
