How to use AJax and json to implement login verification in php

php uses AJax and json to implement login verification: 1. Create a jsp sample file and import jquery dependency and fastjson dependency files; 2. Create a new login.js file to obtain the user name and password text content; 3. , create a new controller class, query whether the user exists and convert the object into a json string type and return it to the js file; 4. js determines whether it is successful and then jumps to the page.

Operating system for this tutorial: Windows 10 system, php8.1.3 version, Dell G3 computer.

AJAX and Json complete user login

1. Import jquery dependencies and fastjson dependencies in advance

2. Create a new jsp page

nbsp;html>



<script></script>
<script></script>

<meta>
<title>Insert title here</title>


		
	<!-- 不使用submit，用ajax+json实现局部刷新，实现登录 -->
	

用户姓名:
用户密码:

3. Create a new js file

$(function(){
	$("#submit").click(function(){
	
		var username = $("#username").val();
		var password = $("#password").val();
		//获取json格式的文本内容
		$.post("login?mark=login",{"username":username,"password":password},
			function(data){
				if(data.log){
					/*输入要跳转的页面*/
					/*window.location.href="https://www.php.cn/link/3729ff995bfa947622cdf0612e57c332";*/
					alert("success");
				}else{
					$("#msg").css("color","red").html(data.msg);
				}
		},"json"
		
		);
		
	});
});

4. Create a new controller class

Query whether This user exists
Convert the map object into a json string type, write it to the memory, and return it to the js file

private void login(HttpServletRequest request, HttpServletResponse response) throws Exception {
		// 
		response.setContentType("text/html;charset=utf-8");
		PrintWriter writer = response.getWriter();
		String msg = "";
		String username = request.getParameter("username");
		String password = request.getParameter("password");
		Map<string> map = new HashMap();
		
		//查询是否存在此用户
		User user = new LoginServer().login(username, password);

		if(user!=null) {
			map.put("log", true);
			map.put("msg", "成功");
		}else {
			map.put("log", false);
			map.put("msg", "用户名或者密码错误");
		}
		
		//把map对象转换成json字符串类型，写入到内存，并返回给js文件
		writer.write(JSON.toJSONString(map));
		
	}</string>

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