Servlet 请求的转发

视频：​​https://www.bilibili.com/video/av94943573​​

文本：

servlet的转发功能、
其中的一些输出就是我的人工断点。
直接通过浏览器，采用GET输入参数
选中的两行提供跳转功能！
最后还是回到了，servlet1
OK！

代码：

servlet1：

package guigu;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class Servlet1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("this is servlet1");
        String name = "";
         name = request.getParameter("username");
        name = new String(name.getBytes("iso-8859-1"),"utf-8");
        System.out.println("this is servlet1 姓名：" + name);
        request.setAttribute("key","柜台1 first!");
        RequestDispatcher requestDispatcher = request.getRequestDispatcher("/s2");
        System.out.println("倒数前两行！");
        requestDispatcher.forward(request,response);
        System.out.println("最后一行！");
    }
}

servlet2：

package guigu;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class Servlet2 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("this is servlet2");
        String name = request.getParameter("username");
        name = new String(name.getBytes("iso-8859-1"),"utf-8");
        System.out.println("this is servlet2:" + name);
        Object key = request.getAttribute("key");
        System.out.println("this is servlet2是否有章---" + key);
        System.out.println("this is servlet2----servlet2处理自己的事务！");
    }
}

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
         version="4.0">
    <servlet>
        <servlet-name>Servlet1</servlet-name>
        <servlet-class>guigu.Servlet1</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>Servlet2</servlet-name>
        <servlet-class>guigu.Servlet2</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>Servlet1</servlet-name>
        <url-pattern>/s1</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>Servlet2</servlet-name>
        <url-pattern>/s2</url-pattern>
    </servlet-mapping>
</web-app>