Springboot使用Mybatisplus：BaseMapper与IService

    

        
            org.springframework.boot
            spring-boot-starter
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        



        
            com.baomidou
            mybatis-plus-boot-starter
            3.4.0
        
        
            mysql
            mysql-connector-java
        

        
            org.projectlombok
            lombok
        



        
            org.springframework.boot
            spring-boot-starter-web
        

    

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    private Long id;
    private String name;
    private Integer age;
    private String email;
}

连接数据库application.yml

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/mybatis_plus?useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver

接口继承baseMapper，简易测试：【仅使用baseMapper中方法可不编写Mapper.xml文件】

mapper接口：

@Repository//@Mapper更专业
public interface UserMapper extends baseMapper {
}

简易测试：

@SpringBootTest
public class SampleTest {

    @Autowired
    private UserMapper userMapper;

    @Test
    public void testSelect() {
        System.out.println(("----- selectAll method test ------"));
        List userList = userMapper.selectList(null);
        assertEquals(5, userList.size());
        userList.forEach(System.out::println);
    }

    @Test
    public void test02(){
        QueryWrapper queryWrapper=new QueryWrapper<>();
        queryWrapper.ge("age",20)
                .le("id",4);
        List users = userMapper.selectList(queryWrapper);
        for (User user : users) {
            System.out.println(user);
        }
    }

在（一）的完全基础上：

@Repository
public interface UserMapper extends baseMapper {
    User selectUserById(Integer id);
}

    
        select * from user
        where id=#{id}
    

spring:
  datasource:
    username: root
    password: 123456
    url: jdbc:mysql://localhost:3306/mybatis_plus?useUnicode=true&characterEncoding=utf-8
    driver-class-name: com.mysql.cj.jdbc.Driver


mybatis-plus:
  mapper-locations: classpath:/mapper/*Mapper.xml

@Autowired
private UserMapper userMapper;

@Test
public void test03(){
    User user = userMapper.selectUserById(3);
    System.out.println(user);
}

在一的基础上：

public interface UserSerivce extends IService {
}

@Service
public class UserServiceImpl extends ServiceImpl implements UserSerivce {

}

@RestController
public class TestController {
    @Autowired
    UserServiceImpl userServiceImpl;
    @RequestMapping("/select")
    public List select(){
        return userServiceImpl.list();
    }
}