HttpServletRequest

HttpServletRequest代表客户端的请求，用户通过Http协议访问服务器，HTTP请求中的所有信息会被封装到HttpServletRequest，通过这个HttpServletRequest的方法，获得客户端的所有信息。

获取前端传递的参数，请求转发

 String getParameter(String var1);
String[] getParameterValues(String var1);

 

LoginServlet.java：

 1 package com.liyu.servlet;
 2 
 3 import javax.servlet.ServletException;
 4 import javax.servlet.http.HttpServlet;
 5 import javax.servlet.http.HttpServletRequest;
 6 import javax.servlet.http.HttpServletResponse;
 7 import java.io.IOException;
 8 import java.util.Arrays;
 9 
10 public class LoginServlet extends HttpServlet {
11     @Override
12     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
13         req.setCharacterEncoding("utf-8");
14         resp.setCharacterEncoding("utf-8");
15 
16         String username = req.getParameter("username");
17         String password = req.getParameter("password");
18         String[] hobbies= req.getParameterValues("hobbies");
19 
20         System.out.println("==================================");
21         //后台接受中文乱码问题
22         System.out.println(username);
23         System.out.println(password);
24         System.out.println(Arrays.toString(hobbies));
25         System.out.println("==================================");
26 
27         //通过请求转发
28         req.getRequestDispatcher("/success.jsp").forward(req,resp);
29     }
30 
31     @Override
32     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
33        doGet(req,resp);
34     }
35 }

 index.jsp:

 1 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
 2 <html>
 3 <head>
 4     <title>登录</title>
 5 </head>
 6 <body>
 7 
 8 <h1>登录</h1>
 9 
10 <div style="text-align: center">
11     <%--这里表单表示的意思是以post的方式提交表单，提交到我们的login请求--%>
12     <form action="${pageContext.request.contextPath}/login" method="post">
13         用户名：<input type="text" name="username"><br>
14         密码：<input type="password" name="password"><br>
15         爱好：
16         <input type="checkbox" name="hobbies" value="女孩">女孩
17         <input type="checkbox" name="hobbies" value="代码">代码
18         <input type="checkbox" name="hobbies" value="唱歌">唱歌
19         <input type="checkbox" name="hobbies" value="电影">电影
20         <br>
21         <input type="submit">
22     </form>
23 </div>
24 </body>
25 </html>

Success.jsp:

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>成功</title>
</head>
<body>
 <h1>
     登录成功
 </h1>
</body>
</html>

w

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
 3          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4          xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
 5         http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd"
 6          version="4.0"
 7          metadata-complete="true">
 8   <display-name>Archetype Created Web Application</display-name>
 9 
10   <servlet>
11     <servlet-name>LoginServlet</servlet-name>
12     <servlet-class>com.liyu.servlet.LoginServlet</servlet-class>
13   </servlet>
14 
15   <servlet-mapping>
16     <servlet-name>LoginServlet</servlet-name>
17     <url-pattern>/login</url-pattern>
18   </servlet-mapping>
19 </web-app>

 

eb.xml:

 

运行测试：

 

重定向和请求转发的区别：

相同点：页面都会实现跳转

不同点：请求转发 url不会产生变化 307

            重定向 url会发生变化 302

 

posted @ 2021-11-11 21:33  liyuSCU  阅读(41)  评论(0)  编辑  收藏  举报