【java】案例 --- 通过JSON数据和Ajax技术实现校验用户名是否存在

regist.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>注册页面</title>
    <script src="js/jquery-3.3.1.min.js"></script>

    <script>
        //在页面加载完成后
        $(function () {
            //给username绑定blur事件
            $("#username").blur(function () {
                //获取username文本输入框的值
                var username = $(this).val();
                //发送ajax请求
                $.get("findUserServlet",{username:username},function (data) {
                    // alert(data);
                    //判断userExsit键的值是否为true
                    var span = $("#s_username");
                    if(data.userExsit){
                        //用户名存在
                        span.css("color","red");
                        span.html(data.msg);
                    }else{
                        //用户名不存在
                        span.css("color","green");
                        span.html(data.msg);
                    }
                }/*,"json"*/);
            });
        });
    </script>
</head>
<body>
    <from>
        <input type="text" id="username" name="username" placeholder="请输入用户名">
        <span id="s_username"></span>
        <br>
        <input type="password" name="password" placeholder="请输入密码"><br>
        <input type="submit" value="注册"><br>
    </from>
</body>
</html>

FindUserServlet.java

package cn.siyi.web.servlet;

import com.fasterxml.jackson.databind.ObjectMapper;

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;
import java.util.HashMap;
import java.util.Map;

@WebServlet("/findUserServlet")
public class FindUserServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //1.获取用户名
        String username = request.getParameter("username");
        //设置相应的数据格式为json
        response.setContentType("application/json;charset=utf-8");
        Map<String,Object> map = new HashMap<String,Object>();
        //2.调用service层判断用户名是否存在
        if("tom".equals(username)){
            //存在
            map.put("userExsit",true);
            map.put("msg","此用户名太受欢迎，请更换一个");
        }else{
            //不存在
            map.put("userExsit",false);
            map.put("msg","用户名可用");
        }
        //将map转为json，并且传递给客户端
        //将map转为json
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.writeValue(response.getWriter(),map);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doPost(request, response);
    }
}

私忆一秒钟

发布了412 篇原创文章 · 获赞 135 · 访问量 4万+

私信关注

【java】案例 --- 通过JSON数据和Ajax技术实现校验用户名是否存在

【java】案例 --- 通过JSON数据和Ajax技术实现校验用户名是否存在

猜你喜欢