Java 小项目开发日记 01（注册接口的开发）

1.项目需求

完成注册接口

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2.项目目录

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3. 配置文件（pom.xml）

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"><modelVersion>4.0.0</modelVersion><!--继承父工程--><parent><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-parent</artifactId><version>3.1.6</version></parent><groupId>com.zhong</groupId><artifactId>big-event</artifactId><version>1.0-SNAPSHOT</version><packaging>jar</packaging><name>big-event</name><url>http://maven.apache.org</url><properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><dependencies><!--web 依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!--MyBatis 依赖--><dependency><groupId>org.mybatis.spring.boot</groupId><artifactId>mybatis-spring-boot-starter</artifactId><version>3.0.0</version></dependency><!--MySQL 依赖--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.29</version></dependency><!--lombok 依赖--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId></dependency><!--参数校验依赖--><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-validation</artifactId></dependency></dependencies>
</project>

SQL 创建表

-- 创建数据库
create database big_event;-- 使用数据库
use big_event;-- 用户表
create table user (id int unsigned primary key auto_increment comment 'ID',username varchar(20) not null unique comment '用户名',password varchar(32)  comment '密码',nickname varchar(10)  default '' comment '昵称',email varchar(128) default '' comment '邮箱',user_pic varchar(128) default '' comment '头像',create_time datetime not null comment '创建时间',update_time datetime not null comment '修改时间'
) comment '用户表';

resources 配置

resources
- application.yml

spring:datasource:driver-class-name: com.mysql.cj.jdbc.Driverurl: jdbc:mysql://localhost:3306/big_eventusername: rootpassword: 123456

Java 代码

controller

UserController

package com.zhong.controller;import com.zhong.pojo.Result;
import com.zhong.pojo.User;
import com.zhong.service.UserService;
import jakarta.validation.constraints.Pattern;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;/*** @ClassName : UserController* @Description : 用户操作* @Author : zhx* @Date: 2024-02-27 20:40*/
@RestController
@RequestMapping("/user")
@Validated
public class UserController {@Autowiredprivate UserService userService;@PostMapping("/register")public Result register(@Pattern(regexp = "^\\S{6,16}$") String username, @Pattern(regexp = "^\\S{6,16}$") String password) {// 查询用户User u = userService.findByUserName(username);if (u == null) {// 没有被占用// 注册userService.registerUser(username, password);return Result.success();} else {// 被占用return Result.error("用户名已被占用......");}}
}

exception

GlobalExceptionHandler

package com.zhong.exception;import com.zhong.pojo.Result;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;/*** @ClassName : GlobalExceptionHandler* @Description : 全局异常处理* @Author : zhx* @Date: 2024-02-27 21:37*/
@RestControllerAdvice
public class GlobalExceptionHandler {@ExceptionHandler(Exception.class)public Result handlerException(Exception e) {e.printStackTrace();return Result.error(StringUtils.hasLength(e.getMessage()) ? e.getMessage() : "操作失败");}
}

mapper

UserMapper

package com.zhong.mapper;import com.zhong.pojo.User;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;
import org.springframework.stereotype.Service;/*** @ClassName : UserMapper* @Description : 用户业务逻辑* @Author : zhx* @Date: 2024-02-27 20:42*/
@Mapper
public interface UserMapper {// 根据用户名查询用户@Select("select * from user where username=#{username}")User findByUserName(String username);// 添加用户@Insert("insert into user(username, password, create_time, update_time) values (#{username}, #{password}, now(), now()) ")void registerUser(String username, String password);
}

pojo

Result

package com.zhong.pojo;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;//统一响应结果
@AllArgsConstructor
@NoArgsConstructor
@Data
public class Result<T> {private Integer code;//业务状态码  0-成功  1-失败private String message;//提示信息private T data;//响应数据//快速返回操作成功响应结果(带响应数据)public static <E> Result<E> success(E data) {return new Result<>(0, "操作成功", data);}//快速返回操作成功响应结果public static Result success() {return new Result(0, "操作成功", null);}public static Result error(String message) {return new Result(1, message, null);}
}

User

package com.zhong.pojo;import lombok.Data;import java.time.LocalDateTime;
@Data
public class User {private Integer id;//主键IDprivate String username;//用户名private String password;//密码private String nickname;//昵称private String email;//邮箱private String userPic;//用户头像地址private LocalDateTime createTime;//创建时间private LocalDateTime updateTime;//更新时间
}

service

impl
- UserServiceImpl

package com.zhong.service.impl;import com.zhong.mapper.UserMapper;
import com.zhong.pojo.User;
import com.zhong.service.UserService;
import com.zhong.utils.Md5Util;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;/*** @ClassName : UserServiceImpl* @Description : 用户接口实现类* @Author : zhx* @Date: 2024-02-27 20:41*/
@Service
public class UserServiceImpl implements UserService {@Autowiredprivate UserMapper userMapper;@Overridepublic User findByUserName(String username) {return userMapper.findByUserName(username);}@Overridepublic void registerUser(String username, String password) {// 加密String md5String = Md5Util.getMD5String(password);// 添加userMapper.registerUser(username, md5String);}
}

UserService

package com.zhong.service;import com.zhong.pojo.User;/*** @ClassName : UserService* @Description : 用户接口* @Author : zhx* @Date: 2024-02-27 20:40*/
public interface UserService {// 根据用户名查询用户User findByUserName(String username);// 注册用户void registerUser(String username, String password);
}

utils

Md5Util

package com.zhong.utils;import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;public class Md5Util {/*** 默认的密码字符串组合，用来将字节转换成 16 进制表示的字符,apache校验下载的文件的正确性用的就是默认的这个组合*/protected static char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};protected static MessageDigest messagedigest = null;static {try {messagedigest = MessageDigest.getInstance("MD5");} catch (NoSuchAlgorithmException nsaex) {System.err.println(Md5Util.class.getName() + "初始化失败，MessageDigest不支持MD5Util。");nsaex.printStackTrace();}}/*** 生成字符串的md5校验值** @param s* @return*/public static String getMD5String(String s) {return getMD5String(s.getBytes());}/*** 判断字符串的md5校验码是否与一个已知的md5码相匹配** @param password  要校验的字符串* @param md5PwdStr 已知的md5校验码* @return*/public static boolean checkPassword(String password, String md5PwdStr) {String s = getMD5String(password);return s.equals(md5PwdStr);}public static String getMD5String(byte[] bytes) {messagedigest.update(bytes);return bufferToHex(messagedigest.digest());}private static String bufferToHex(byte bytes[]) {return bufferToHex(bytes, 0, bytes.length);}private static String bufferToHex(byte bytes[], int m, int n) {StringBuffer stringbuffer = new StringBuffer(2 * n);int k = m + n;for (int l = m; l < k; l++) {appendHexPair(bytes[l], stringbuffer);}return stringbuffer.toString();}private static void appendHexPair(byte bt, StringBuffer stringbuffer) {char c0 = hexDigits[(bt & 0xf0) >> 4];// 取字节中高 4 位的数字转换, >>>// 为逻辑右移，将符号位一起右移,此处未发现两种符号有何不同char c1 = hexDigits[bt & 0xf];// 取字节中低 4 位的数字转换stringbuffer.append(c0);stringbuffer.append(c1);}
}

BigEventApplication

package com.zhong;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
public class BigEventApplication {public static void main(String[] args) {SpringApplication.run(BigEventApplication.class, args);}
}