JAVAWEB入门：HttpServletRequest的应用·实现一个简单的登陆系统-CFANZ编程社区

HttpServletRequest的应用

1.简介：

在这里插入图片描述

2.index.jsp文件

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
  <title>登录 - IMUST</title>
</head>
<body>
<a href="/Login">点击跳转~</a>
<hr>
<h3>get方法表单</h3>
<form action="/Login" method="get">
  用户名：<input type="text" name="userName"><br>
  密码：<input type="password" name="passWord"><br>
  重新输入密码：<input type="password" name="agPassword"><br>
  <input type="submit" name="Submite">
</form>
<hr>
<h3>post方法表单</h3>
<form action="/Login" method="post">
  用户名：<input type="text" name="userName"><br>
  密码：<input type="password" name="passWord"><br>
  重新输入密码：<input type="password" name="agPassword"><br>
  <input type="checkbox" name="hobby" value="sing"> 唱
  <input type="checkbox" name="hobby" value="dance"> 跳
  <input type="checkbox" name="hobby" value="rap"> rap
  <input type="checkbox" name="hobby" value="basketball"> 篮球<br>
  <input type="submit" name="Submite">
</form>
</body>
</html>

3.Login.java

package IMUSTCTF;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.Map;


public class Login extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/hmtl;charset=utf-8");
        String data = "中华人民共和国";
        PrintWriter out = response.getWriter();
        out.println(data);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        response.setContentType("text/hmtl;charset=utf-8");
        // 登录系统参数的获取,getParameter方法
        String userName = request.getParameter("userName");
        String passWord = request.getParameter("passWord");
        // 登录系统爱好参数的获取，getParameterMap方法
        Map map = new HashMap();
        map = request.getParameterMap();
        // map.get()返回的结果要转成字符串数组，而不能直接转成String，否则会输出：[Ljava.lang.String;
        String[] hobby = (String[])map.get("hobby");

        PrintWriter out = response.getWriter();

        // 获取用户的用户名及密码，测试账户
        String rightUsername = "imust";
        String rightPassword = "imust20";

        // 检测用户输入的正确性
        if(userName.equals(rightUsername) && passWord.equals(rightPassword)){
            out.println("您的用户名:" +userName);
            out.println("您的密码:" +passWord);
            for(int i = 1 ; i <= hobby.length ; i ++){
                out.println("您的第"+ i +"个爱好:" +hobby[i-1]);
            }
        }
        else{
            out.println("用户名或密码错误！！！");
        }
    }
}