Request response application to obtain front-end information


## 首先配置web.xml文件

<?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"
         metadata-complete="true">

    <servlet>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>com.study.servlet.LoginServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LoginServlet</servlet-name>
        <url-pattern>/login</url-pattern>
    </servlet-mapping>
</web-app>


## 新建两个jsp页面

## 1.index.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>登录</title>
</head>
<body>
<h1>登录</h1>
<div style="text-align: center">
    <form action="${pageContext.request.contextPath}/login" method="post">
        用户名:<input type="text"  name="username"> <br>
        密码:<input type="password"  name="password"> <br>
        爱好:
        <input type="checkbox" name="hobby" value="女孩">女孩
        <input type="checkbox" name="hobby" value="代码">代码
        <input type="checkbox" name="hobby" value="唱歌">唱歌
        <input type="checkbox" name="hobby" value="电影">电影
        <br>
        <input type="submit">
    </form>


</div>
</body>
</html>

## 2.success.jsp

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

## request方法

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


public class LoginServlet extends HttpServlet {
    
    


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
        req.setCharacterEncoding("utf-8");
        resp.setCharacterEncoding("utf-8");
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String[] hobbys = req.getParameterValues("hobbys");
        System.out.println("========================");
//        后台乱码问题解决
        System.out.println(username);
        System.out.println(password);
        System.out.println(Arrays.toString(hobbys));
//        打印输出的字段名
        System.out.println("========================");
        System.out.println(req.getContextPath());
//        通过请求转发
        req.getRequestDispatcher("/success.jsp").forward(req,resp);

    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
    
    
        doGet(req,resp);
    }
}
Request response application to obtain front-end information

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