HttpServletRequest

Mahe666

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

获取前端参数，并进行请求转发

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 Login extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setCharacterEncoding("UTF-8");
        req.setCharacterEncoding("UTF-8");

        String username = req.getParameter("username");
        String password = req.getParameter("password");
        String[] hobbies = req.getParameterValues("hobbies");

        System.out.println(username);
        System.out.println(password);
        System.out.println(Arrays.toString(hobbies));

        //通过请求转发，同级跳转直接跳 /页面
            //注意！重定向需要写项目名，转发不用
            //req.getContextPath()
        req.getRequestDispatcher("/success.jsp").forward(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doGet(req, resp);
    }
}

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"
         metadata-complete="true">

    <servlet>
        <servlet-name>login</servlet-name>
        <servlet-class>com.mahe666.servlet.Login</servlet-class>
    </servlet>

    <servlet-mapping>
        <servlet-name>login</servlet-name>
        <url-pattern>/login</url-pattern>
    </servlet-mapping>

</web-app>

webapp/index.jsp

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

<div style="text-align: center">
    <%--${pageContext.request.contextPath}代表的是项目名--%>
    <form action="${pageContext.request.contextPath}/login" method="get">
        username:<input type="text" name="username"><br>
        password:<input type="password" name="password"><br>
        hobbies:
        <input type="checkbox" name="hobbies" value="美女">美女
        <input type="checkbox" name="hobbies" value="代码">代码
        <input type="checkbox" name="hobbies" value="唱歌">唱歌
        <input type="checkbox" name="hobbies" value="电影">电影
        <br>
        <input type="submit">
    </form>
</div>

</body>
</html>

webapp/success.jsp

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

<h2>登陆成功</h2>

</body>
</html>