Servlet（三）

流程分析

代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>登录页面</title>
</head>
<body>
    <form action="/login_war_exploded/login" method="post">
        用户名<input type="text" name="username"><br>
        密码<input type="text" name="password"><br>
        <input type="submit" value="登录">
    </form>
</body>
</html>

配置web.xml文件，将login.html设置为welcome页面

<?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_3_1.xsd"
         version="3.1">
    <!--自定义welcome页面-->
    <welcome-file-list>
        <welcome-file>login.html</welcome-file>
    </welcome-file-list>
</web-app>

LoginServlet

package LoginDemo;
  
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;
  
@WebServlet("/login")
public class LoginServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doGet(request, response);
    }
  
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1. 使用request获取请求参数
        String username = request.getParameter("username");
        String password = request.getParameter("password");
  
        //2. 校验用户名和密码
        if ("jay".equals(username) && "123456".equals(password)) {
            //登录成功
            response.getWriter().write("login success");
        }else {
            //登录失败
            response.getWriter().write("login failed");
        }
    }
}

发布项目，浏览器跳转到welcome页面，输入正确的用户名与密码，点击登录按钮可以看到页面输出login success
而当输入错误的用户名与密码后，点击登录可以看到页面输出login failed

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