创建controller/service/mapper/impl过程

先创建entity包，在里面导入实体类

然后创建controller/mapper/service包

然后在service里创建impl包

然后在mapper包里写mapper接口，加上@Mapper注解，继承BaseMapper<Employee>，泛型是实体类

 

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

 由于继承，把常见增删改查都有了

然后创建service，继承IService<Employee>泛型是实体类

 

public interface EmployeeService extends IService<Employee> {
}

然后创建service的实现类，加上@Servise注解，extends ServiceImpl<>泛型是EmployeeMapper和Employee，实现implements EmployeeService

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

然后创建controller，访问路径注解，注入service

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

 创建common包，在里面导入R类，返回结果类

package com.itheima.reggie.common;

import lombok.Data;

import java.util.HashMap;
import java.util.Map;

/**
 * 通用返回结果，服务端响应的数据最终都会封装成此对象
 * @param <T>
 */
@Data
public class R<T> {

    private Integer code; //编码：1成功，0和其它数字为失败

    private String msg; //错误信息

    private T data; //数据

    private Map map = new HashMap(); //动态数据

    public static <T> R<T> success(T object) {
        R<T> r = new R<T>();
        r.data = object;
        r.code = 1;
        return r;
    }

    public static <T> R<T> error(String msg) {
        R r = new R();
        r.msg = msg;
        r.code = 0;
        return r;
    }

    public R<T> add(String key, Object value) {
        this.map.put(key, value);
        return this;
    }

}