1.jsp跳转jsp

jsp1代码

<%--
  Created by IntelliJ IDEA.
  User: 49841
  Date: 2020/9/7
  Time: 21:33
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>ajax</title>
</head>
<body>
    <form action="index.jsp">
        用户名：<input type="text" name="username">
        <input type="submit" value="提交">
    </form>
<%--<%
    String username = request.getParameter("username");
    System.out.println("在登陆界面得到的username值："+username);
    request.getSession().setAttribute("name", username);
%>--%>
</body>
</html>

jsp2代码

<%--
  Created by IntelliJ IDEA.
  User: 49841
  Date: 2020/9/7
  Time: 10:33
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
      <%--<%
          /*String username1 = request.getParameter("username");
          System.out.println("在index界面得到的username值："+username1);*/
          String username = request.getParameter("username");
          request.setAttribute("username", username);
          /*request.getSession().setAttribute("username", username1);
          System.out.println("session中的username值："+request.getSession().getAttribute("username"));*/
      %>--%>
      <h2>欢迎来到主页面，呱？！</h2>
      <span>显示用户名getSession：</span>  <span>${param.username}</span> <br/>
<%--      <span>显示用户名getSession：</span>  <span>${servletname}</span> <br/>--%>

<%--      <span>显示用户名getParameter：</span><span>${username1}</span> <br/>--%>
<%--      <span>显示用户名getParameter：</span><span>username1</span> <br/>--%>
  </body>
</html>

1.这种使用的是${param.username}获取第一个界面传来的数据。

2.也可以在上面先得到前一个jsp页面传来的参数，再讲参数放到request或者其他域中，然后使用${username}得到

 String username = request.getParameter("username");
 request.setAttribute("username", username);

 <span>显示用户名getSession：</span>  <span>${param.username}</span> <br/>

2.jsp跳转servlet跳转jsp

jsp1页面代码

<%--
  Created by IntelliJ IDEA.
  User: 49841
  Date: 2020/9/7
  Time: 21:33
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>ajax</title>
</head>
<body>
    <form action="TestServlet1">
        用户名：<input type="text" name="username">
        <input type="submit" value="提交">
    </form>
<%--<%
    String username = request.getParameter("username");
    System.out.println("在登陆界面得到的username值："+username);
    request.getSession().setAttribute("name", username);
%>--%>
</body>
</html>

servlet代码

package servlet;

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 java.io.IOException;

/**
 * zt
 * 2020/9/7
 * 22:17
 */
@WebServlet(value = "/TestServlet1")
public class TestServlet1 extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String jspname = request.getParameter("username");
        System.out.println("在servlet中得到的值："+jspname);
//        request.setAttribute("servletname", jspname);
        request.getRequestDispatcher("/index.jsp").forward(request, response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doPost(request, response);
    }
}

jsp2页面代码

<%--
  Created by IntelliJ IDEA.
  User: 49841
  Date: 2020/9/7
  Time: 10:33
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title>$Title$</title>
  </head>
  <body>
      <%--<%
          /*String username1 = request.getParameter("username");
          System.out.println("在index界面得到的username值："+username1);*/
          String username = request.getParameter("username");
          request.setAttribute("username", username);
          /*request.getSession().setAttribute("username", username1);
          System.out.println("session中的username值："+request.getSession().getAttribute("username"));*/
      %>--%>
      <h2>欢迎来到主页面，呱？！</h2>
      <span>显示用户名getSession：</span>  <span>${param.username}</span> <br/>
<%--      <span>显示用户名getSession：</span>  <span>${servletname}</span> <br/>--%>

<%--      <span>显示用户名getParameter：</span><span>${username1}</span> <br/>--%>
<%--      <span>显示用户名getParameter：</span><span>username1</span> <br/>--%>
  </body>
</html>

1.这种方法jsp2页面代码不变，还是使用${param.username}来得到传来的参数，它们三个互相传递的也都是参数 2.还可以在servlet中将得到的参数放在域中，然后在jsp2界面里从域中获取属性一样可以得到（不要将参数和属性搞混掉），参数是getParameter得到的，属性是getAttribute得到的。

jsp跳转jsp----------和------------jsp跳转servlet跳转jsp

1.jsp跳转jsp

2.jsp跳转servlet跳转jsp