案例开发-日程管理4（用Ajax实现注册提交前校验用户名是否占用）超详细、超基础

文章目录

[1. 客户端代码编写处理](#1. 客户端代码编写处理)
- [1.1 regist.html页面代码](#1.1 regist.html页面代码)
[2. 服务端代码处理](#2. 服务端代码处理)
- [2.1 创建一个枚举类（业务含义和状态码对应关系的枚举）](#2.1 创建一个枚举类（业务含义和状态码对应关系的枚举）)
- 2.2全局统一响应的JSON格式处理类
- 2.3增加Jackson依赖
- 2.4添加WEBUtil工具类
[3. 用户名校验业务接口代码](#3. 用户名校验业务接口代码)

1. 客户端代码编写处理

1.1 regist.html页面代码

html 复制代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>

        .ht{
            text-align: center;
            color: cadetblue;
            font-family: 幼圆;
        }
        .tab{
            width: 500px;
            border: 5px solid cadetblue;
            margin: 0px auto;
            border-radius: 5px;
            font-family: 幼圆;
        }
        .ltr td{
            border: 1px solid  powderblue;

        }
        .ipt{
            border: 0px;
            width: 50%;

        }
        .btn1{
            border: 2px solid powderblue;
            border-radius: 4px;
            width:60px;
            background-color: antiquewhite;

        }

        .msg {
            color: gold;
        }

        .buttonContainer{
            text-align: center;
        }
    </style>

    <script>

        // 校验用户名的方法
        function checkUsername(){
            // 定义正则
            var usernameReg=/^[a-zA-Z0-9]{5,10}$/
            var username =document.getElementById("usernameInput").value
            var usernameMsgSpan =document.getElementById("usernameMsg")
            if(!usernameReg.test(username)){
                usernameMsgSpan.innerText="不合法"
                return false
            }
            // 发送ajax请求校验用户名是否被占用
            var request;
            if(window.XMLHttpRequest){
                request= new XMLHttpRequest();
            }else{
                request= new ActiveXObject("Microsoft.XMLHTTP");
            }
            request.onreadystatechange= function (){
                // request.readyState == 4 代表请求结束,已经接收到响应结果
                // request.status== 200  表示后端响应状态码是200
                if(request.readyState == 4  && request.status== 200){
                    // 后端的响应的JSON字符串转换为前端的对象
                    var response =JSON.parse(request.responseText)
                    console.log(response)
                    //  判断业务码是否是200
                    if (response.code != 200){
                        usernameMsgSpan.innerText="已占用"
                        return false
                    }
                }
            }
            // 设置请求方式,请求资源路径,是否为异步请求
            request.open("GET",'/user/checkUsernameUsed?username='+username,true)
            // 发送请求
            request.send();
            // 前面校验都通过
            // usernameMsgSpan.innerText="OK"
            // return true

        }


        // 校验密码的方法
        function checkUserPwd(){
            // 定义正则
            var passwordReg=/^[0-9]{6}$/
            var userPwd =document.getElementById("userPwdInput").value
            var userPwdMsgSpan =document.getElementById("userPwdMsg")
            if(!passwordReg.test(userPwd)){
                userPwdMsgSpan.innerText="不合法"
                return false
            }
            userPwdMsgSpan.innerText="OK"
            return true
        }

        // 校验密码的方法
        function checkReUserPwd(){
            // 定义正则
            var passwordReg=/^[0-9]{6}$/
            var userPwd =document.getElementById("userPwdInput").value
            var reUserPwd =document.getElementById("reUserPwdInput").value
            var reUserPwdMsgSpan =document.getElementById("reUserPwdMsg")
            if(!passwordReg.test(userPwd)){
                reUserPwdMsgSpan.innerText="不合法"
                return false
            }
            if(userPwd != reUserPwd){
                reUserPwdMsgSpan.innerText="不一致"
                return false

            }
            reUserPwdMsgSpan.innerText="OK"
            return true
        }

        //表单提交时统一校验
        function checkForm(){
            return checkUsername() && checkUserPwd() && checkReUserPwd()
        }



    </script>
</head>
<body>
<h1 class="ht">欢迎使用日程管理系统</h1>
<h3 class="ht">请注册</h3>
<form method="post" action="/user/regist" onsubmit="return checkForm()">
    <table class="tab" cellspacing="0px">
        <tr class="ltr">
            <td>请输入账号</td>
            <td>
                <input class="ipt" id="usernameInput" type="text" name="username" onblur="checkUsername()">
                <span id="usernameMsg" class="msg"></span>
            </td>
        </tr>
        <tr class="ltr">
            <td>请输入密码</td>
            <td>
                <input class="ipt" id="userPwdInput" type="password" name="userPwd" onblur="checkUserPwd()">
                <span id="userPwdMsg" class="msg"></span>
            </td>
        </tr>
        <tr class="ltr">
            <td>确认密码</td>
            <td>
                <input class="ipt" id="reUserPwdInput" type="password" onblur="checkReUserPwd()">
                <span id="reUserPwdMsg" class="msg"></span>
            </td>
        </tr>
        <tr class="ltr">
            <td colspan="2" class="buttonContainer">
                <input class="btn1" type="submit" value="注册">
                <input class="btn1" type="reset" value="重置">
                <button class="btn1"><a  href="/login.html">去登录</a></button>
            </td>
        </tr>
    </table>
</form>
</body>
</html>

2. 服务端代码处理

2.1 创建一个枚举类（业务含义和状态码对应关系的枚举）

java 复制代码

/**
 * 业务含义和状态码对应关系的枚举
 *
 */
public enum ResultCodeEnum {

    SUCCESS(200,"success"),
    USERNAME_ERROR(501,"usernameError"),
    PASSWORD_ERROR(503,"passwordError"),
    NOTLOGIN(504,"notLogin"),
    USERNAME_USED(505,"userNameUsed")
    ;

    private Integer code;
    private String message;
    private ResultCodeEnum(Integer code, String message) {
        this.code = code;
        this.message = message;
    }
    public Integer getCode() {
        return code;
    }
    public String getMessage() {
        return message;
    }
}

2.2全局统一响应的JSON格式处理类

java 复制代码

/**
 * 全局统一响应的JSON格式处理类
 *
 */
public class Result<T> {
    // 返回码
    private Integer code;
    // 返回消息
    private String message;
    // 返回数据
    private T data;
    public Result(){}
    // 返回数据
    protected static <T> Result<T> build(T data) {
        Result<T> result = new Result<T>();
        if (data != null)
            result.setData(data);
        return result;
    }
    public static <T> Result<T> build(T body, Integer code, String message) {
        Result<T> result = build(body);
        result.setCode(code);
        result.setMessage(message);
        return result;
    }
    public static <T> Result<T> build(T body, ResultCodeEnum resultCodeEnum) {
        Result<T> result = build(body);
        result.setCode(resultCodeEnum.getCode());
        result.setMessage(resultCodeEnum.getMessage());
        return result;
    }
    /**
     * 操作成功
     * @param data  baseCategory1List
     * @param <T>
     * @return
     */
    public static<T> Result<T> ok(T data){
        Result<T> result = build(data);
        return build(data, ResultCodeEnum.SUCCESS);
    }
    public Result<T> message(String msg){
        this.setMessage(msg);
        return this;
    }
    public Result<T> code(Integer code){
        this.setCode(code);
        return this;
    }
    public Integer getCode() {
        return code;
    }
    public void setCode(Integer code) {
        this.code = code;
    }
    public String getMessage() {
        return message;
    }
    public void setMessage(String message) {
        this.message = message;
    }
    public T getData() {
        return data;
    }
    public void setData(T data) {
        this.data = data;
    }
}

2.3增加Jackson依赖

2.4添加WEBUtil工具类

实现JSON串格式的转换

java 复制代码

package com.atguigu.schedule.util;


import com.atguigu.schedule.common.Result;
import com.fasterxml.jackson.databind.ObjectMapper;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;

import java.io.BufferedReader;
import java.io.IOException;
import java.text.SimpleDateFormat;

public class WebUtil {
    private static ObjectMapper objectMapper;
    // 初始化objectMapper
    static{
        objectMapper=new ObjectMapper();
        // 设置JSON和Object转换时的时间日期格式
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
    }
    // 从请求中获取JSON串并转换为Object
    public static <T> T readJson(HttpServletRequest request,Class<T> clazz){
        T t =null;
        BufferedReader reader = null;
        try {
            reader = request.getReader();
            StringBuffer buffer =new StringBuffer();
            String line =null;
            while((line = reader.readLine())!= null){
                buffer.append(line);
            }

            t= objectMapper.readValue(buffer.toString(),clazz);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
        return t;
    }
    // 将Result对象转换成JSON串并放入响应对象
    public static void writeJson(HttpServletResponse response, Result result){
        response.setContentType("application/json;charset=UTF-8");
        try {
            String json = objectMapper.writeValueAsString(result);
            response.getWriter().write(json);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

3. 用户名校验业务接口代码

在SysUserController中实现

java 复制代码

  /** 
     * SysUserController下,注册时校验用户名是否被占用的业务接口
     * @param req
     * @param resp
     * @throws ServletException
     * @throws IOException
     */
    protected void checkUsernameUsed(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String username = req.getParameter("username");
        SysUser registUser = userService.findByUsername(username);

        //封装结果对象
        Result result=null;
        if(null ==registUser){
            // 未占用,创建一个code为200的对象
            result= Result.ok(null);
        }else{
            // 占用, 创建一个结果为505的对象
            result= Result.build(null, ResultCodeEnum.USERNAME_USED);

        }
        // 将result对象转换成JSON并响应给客户端
        WebUtil.writeJson(resp,result);

    }