Ajax实现登录案例

Ajax登录案例，供大家参考，具体内容如下

Msg

package com.lbl.msg;

public class Msg {
String msg;
int code;

public Msg() {
}

public Msg(String msg, int code) {
this.msg = msg;
this.code = code;
}

public String getMsg() {
return msg;
}

public void setMsg(String msg) {
this.msg = msg;
}

public int getCode() {
return code;
}

public void setCode(int code) {
this.code = code;
}
}

RegisterServlet

package com.lbl.servlet;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.lbl.msg.Msg;

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(\”/register\”)
public class RegisterServlet extends HttpServlet {
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1:获取请求发送的数据
String username = request.getParameter(\”username\”);
response.setContentType(\”text/html;charset=UTF-8\”);
//2:判断用户名是否注册
if(\”abc123\”.equals(username)){
Msg msg = new Msg(\”用户名已经注册\”,0);
//用户名已经注册 {\”flag\”:false,\”info\”:\”用户名已经注册\”};
// String jsonStr = \”{\\\”flag\\\”:false,\\\”info\\\”:\\\”用户名已经注册\\\”}\”;
//响应回浏览器
response.getWriter().write(new ObjectMapper().writeValueAsString(msg));
}else{
Msg msg = new Msg(\”可以注册\”,1);
//用户名没有注册
// String jsonStr = \”{\\\”flag\\\”:true,\\\”info\\\”:\\\”可以注册\\\”}\”;
//响应回浏览器
response.getWriter().write(new ObjectMapper().writeValueAsString(msg));
}

}
}

json_register.html

<!DOCTYPE html>
<html lang=\”en\”>
<head>
<meta charset=\”UTF-8\”>
<title>Title</title>
<script src=\”js/jquery-3.3.1.js\”></script>
<script type=\”application/javascript\”>
$(function () {
//1: 给用户名输入框绑定失去焦点事件(onfocus onblur)
$(\”#username\”).on(\”blur\”,function () {
//获取用户名输入框数据
var username = $(\”#username\”).val();
//2:向服务器发出异步请求，让服务器去查询用户名是否存在
$.post(
\”register\”, //表示服务器的servlet路径
\”username=\”+username, //表示向服务器发送的数据
function (data) { // msg:用户名已经注册 code:0
if(data.code==0){
// alert(data.info);
$(\”#spanId\”).html(data.msg).css(\”color\”,\”green\”);
}else {
$(\”#spanId\”).html(data.msg).css(\”color\”,\”red\”);
}

},
\”json\”
);
});
});

</script>
</head>
<body>
<div>
<font>会员注册</font>USER REGISTER
<form class=\”form-horizontal\” style=\”margin-top: 5px;\”>
<table>
<tr>
<td>用户名</td>
<td>
<input type=\”text\” id=\”username\” name=\”username\” placeholder=\”请输入用户名\”>
<span id=\”spanId\”></span>
</td>
</tr>
<tr>
<td>密码</td>
<td>
<input type=\”password\” placeholder=\”请输入密码\”>
</td>
</tr>
</table>
<input type=\”submit\” value=\”注册\”/>
</form>
</div>