Java中Request请求转发详解

直接来，RequestDemo5代码，get请求和post请求都请求转发了，转发到RequestDemo6请求

 RequestDemo5代码

package com.lingaolu.request;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;

/**
* @author 林高禄
* @create 2020-07-07-12:06
*/
@WebServlet("/requestDemo5")
public class RequestDemo5 extends HttpServlet {

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("requestDemo5进来了......post");
RequestDispatcher requestDispatcher = request.getRequestDispatcher("/requestDemo6");
requestDispatcher.forward(request,response);
}

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("requestDemo5进来了......get");
RequestDispatcher requestDispatcher = request.getRequestDispatcher("/requestDemo6");
requestDispatcher.forward(request,response);

}
}

RequestDemo6代码

package com.lingaolu.request;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;

/**
* @author 林高禄
* @create 2020-07-07-12:06
*/
@WebServlet("/requestDemo6")
public class RequestDemo6 extends HttpServlet {

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("requestDemo6进来了......post");
}

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("requestDemo6进来了......get");
}
}

浏览器访问/requestDemo5接口

控制台输出

从以上结果可以看出

请求过后我们的浏览器地址还是http://localhost:8080/myRequest/requestDemo5

从浏览器的F12调试页面可以看出，转发只是一次请求，只有/requestDemo5请求，说明，可共享数据Request共享数据

我们用Postman进行post请求一下

后台输出：

可见，get请求的转发会转发到get请求，post请求的转发，会转发到post请求

我们改一下RequestDemo5的代码，转发到百度

package com.lingaolu.request;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;

/**
* @author 林高禄
* @create 2020-07-07-12:06
*/
@WebServlet("/requestDemo5")
public class RequestDemo5 extends HttpServlet {

@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("requestDemo5进来了......post");
RequestDispatcher requestDispatcher = request.getRequestDispatcher("/requestDemo6");
requestDispatcher.forward(request,response);
}

@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
System.out.println("requestDemo5进来了......get");
RequestDispatcher requestDispatcher = request.getRequestDispatcher("https://www.baidu.com/");
requestDispatcher.forward(request,response);

}
}

浏览器请求

 后台输出：

从后台输出看出，requestDemo5请求进来了，从浏览器看出，转发失败了，而且从实际转发的路径上看，因为虚拟路径，所以请求转发只能转发到当前服务器内部的资源

请求转发的特点总结：（与之对应的------重定向的详情与特点）

• 浏览器地址栏路径不发生变化

• 转发只是一次请求，可共享数据Request共享数据

• 哪种请求方式只能转发到那种请求方式

• 请求转发只能转发到当前服务器内部的资源

来源：https://blog.csdn.net/lgl782519197/article/details/107183540