model层=entity层=实体类

存放我们的实体类，与数据库中的属性值基本保持一致。

// Employee
@Data
public class Employee implements Serializable {
    private static final long serialVersionUID = 1L;
    private Long id;
    private String username;
    private String name;
    private String password;
    private String phone;
    private String sex;
    private String idNumber;
    private Integer status;
    private LocalDateTime createTime;
    private LocalDateTime updateTime;

    // 字段自动填充
    @TableField(fill = FieldFill.INSERT)
    private Long createUser;

    // 字段自动填充
    @TableField(fill = FieldFill.INSERT_UPDATE)
    private Long updateUser;

}

Mapper层=Dao层

对数据库进行数据持久化操作，他的方法语句是直接针对数据库操作的

// mapper
@Mapper
public interface EmployeeMapper extends BaseMapper<Employee> {}

Service层

存放业务逻辑处理，也是一些关于数据库处理的操作

// Service
@Service
public interface EmployeeService extends IService<Employee> {}

// ServiceImpl
@Service
public class EmployeeServiceImpl extends ServiceImpl<EmployeeMapper, Employee> 
	implements EmployeeService {
}

controller层

controller通过接收前端传过来的参数进行业务操作

• 学习MD5加密
• 学习查询数据库
• 学习session的使用

// Controller
@Slf4j
@RestController
@RequestMapping("/employee")
public class EmployeeController {
    @Autowired
    private EmployeeService employeeService;

    @PostMapping("/login")
    public R<Employee> login(HttpServletRequest request, @RequestBody Employee employee) {
        // 1. md5加密
        String password = employee.getPassword();
        password = DigestUtils.md5DigestAsHex(password.getBytes());
        // 2. 查询数据库，通过名称查询用户
        LambdaQueryWrapper<Employee> queryWapper = new LambdaQueryWrapper<>();
        queryWapper.eq(Employee::getUsername, employee.getUsername());
        Employee emp = employeeService.getOne(queryWapper);
        // 3. 判断是否查到
        if(emp == null) {
            return R.error("登录失败");
        }
        // 4. 如果密码不一致
        if(!emp.getPassword().equals(password)) {
            return R.error("密码不一致");
        }
        // 5. 查看用户是否被禁用
        if(emp.getStatus() == 0) {
            return R.error("用户被禁用");
        }
				
				// 设置session
        request.getSession().setAttribute("employee", emp.getId());
        return R.success(emp);
    }

			@PostMapping("/logout")
	    public R<String> logout(HttpServletRequest request) {
	        request.getSession().removeAttribute("employee");
	        return R.success("退出登录成功");
	    }
}