广州免费核酸在哪里做西安seo推广公司

一、新建项目

• 新建项目，项目名称logindemo，组名为my，用的java21去写的，用的包管理为maven
  
• 添加依赖，我这边使用的3.4.3版本，添加了4个依赖
  

二、设计数据库

• 设计表单，设置一个自增的主键uid，然后再设置一下账号和密码的类型
  
• 添加测试账号
  

三、配置数据库

• 找到配置文件application.properties
  
• 输入数据库相关配置信息，此处配置了项目端口号为8082，可不配置，默认端口号为8080【注意：配置url处logindemo改为你的数据库名称】

spring.application.name=logindemo# 配置端口号为8082
server.port=8082# 配置数据库
# 配置驱动
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
# 若连接的是云数据库则将localhost改为云端ip
spring.datasource.url=jdbc:mysql://localhost:3306/logindemo?serverTimezone=UTC
# Mysql用户
spring.datasource.username=root
# Mysql对应用户密码
spring.datasource.password=123456# 配置MyBatis
mybatis.mapper-locations=classpath:mybatis
mybatis.type-aliases-package=com.my.logindemo.domain

四、实体类

• 实体类里面的变量名称要与数据库的变量名称对应

package com.my.logindemo.domain;public class User {private int uid;private String uname;private String password;public int getUid() {return uid;}public void setUid(int uid) {this.uid = uid;}public String getUname() {return uname;}public void setUname(String uname) {this.uname = uname;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}
}

四、Dao层的实现

• 这里有2个方法，一个是找对应的账号和密码来实现登录功能，第二个就是查找账号来实现注册功能（账号唯一性）
• 注意这里使用的是mybatis的方法

package com.my.logindemo.repository;import com.my.logindemo.domain.User;@org.apache.ibatis.annotations.Mapper
public interface UserDao {User findByUname(String uname);User findByUnameAndPassword(String uname, String password);int insertUser(User user);
}

五、配置mybatis

• namespace用来映射自己的dao层
• id绑定对应dao层的方法
• user为自己数据库的名字

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="com.my.logindemo.repository.UserDao"><select id="findByUname" resultType="com.my.logindemo.domain.User">SELECT * FROM user WHERE uname = #{uname}</select><select id="findByUnameAndPassword" resultType="com.my.logindemo.domain.User">SELECT * FROM user WHERE uname = #{uname} AND password = #{password}</select><insert id="insertUser" parameterType="com.my.logindemo.domain.User">INSERT INTO user (uname, password) VALUES (#{uname}, #{password})</insert>
</mapper>

六、实现service层

• 我们这里先看一下service

package com.my.logindemo.service;
import com.my.logindemo.domain.User;public interface UserService {/*** 登录业务逻辑* @param uname 账户名* @param password 密码* @return*/User loginService(String uname, String password);/*** 注册业务逻辑* @param user 要注册的User对象，属性中主键uid要为空，若uid不为空可能会覆盖已存在的user* @return*/User registService(User user);
}

• 第二个就是servicelmpl

package com.my.logindemo.service.servicelmpl;import com.my.logindemo.service.UserService;
import com.my.logindemo.domain.User;
import com.my.logindemo.repository.UserDao;
import org.springframework.stereotype.Service;
import jakarta.annotation.Resource;@Service
public class UserServicelmpl implements UserService{@Resourceprivate UserDao userDao;@Overridepublic User loginService(String uname, String password) {User user = userDao.findByUnameAndPassword(uname, password);// 重要信息置空if(user != null){user.setPassword("");}return user;}@Overridepublic User registService(User user) {//当新用户的用户名已存在时if(userDao.findByUname(user.getUname())!=null){// 无法注册return null;}else{// 插入用户到数据库int result = userDao.insertUser(user);if (result > 0) {//返回创建好的用户对象user.setPassword("");return user;} else {return null;}}}
}

七、自定义工具类

• 自定义一个信息回复

package com.my.logindemo.utils;public class Result<T> {private String code;private String msg;private T data;public String getCode() {return code;}public void setCode(String code) {this.code = code;}public String getMsg() {return msg;}public void setMsg(String msg) {this.msg = msg;}public T getData() {return data;}public void setData(T data) {this.data = data;}public Result() {}public Result(T data) {this.data = data;}public static Result success() {Result result = new Result<>();result.setCode("200");result.setMsg("成功");return result;}public static <T> Result<T> success(T data) {Result<T> result = new Result<>(data);result.setCode("200");result.setMsg("成功");return result;}public static <T> Result<T> success(T data,String msg) {Result<T> result = new Result<>(data);result.setCode("200");result.setMsg(msg);return result;}public static Result error(String code, String msg) {Result result = new Result();result.setCode(code);result.setMsg(msg);return result;}
}

八、实现controller层

package com.my.logindemo.controller;import com.my.logindemo.domain.User;
import com.my.logindemo.service.UserService;
import com.my.logindemo.utils.Result;
import org.springframework.web.bind.annotation.*;
import jakarta.annotation.Resource;@RestController
public class UserController {@Resourceprivate UserService userService;@PostMapping("/login")public Result<User> loginController(@RequestBody User newUser){User user = userService.loginService(newUser.getUname(),newUser.getPassword());if(user!=null){return Result.success(user,"登录成功！");}else{return Result.error("403","账号或密码错误！");}}@PostMapping("/register")public Result<User> registController(@RequestBody User newUser){User user = userService.registService(newUser);if(user!=null){return Result.success(user,"注册成功！");} else{return Result.error("403","用户名已存在！");}}
}

九、测试

• 使用postman进行登录和注册功能的测试