# Mybatis 로 Mysql 연결하기

#### pom.xml

```xml
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.1</version>
</dependency>

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
</dependency>
```

#### mybatis-spring-boot-starter

* 2.1.x vesrion : MyBatis 3.5+、Java 8+、Spring Boot 2.1+
* 2.0.x vesrion : MyBatis 3.5+、Java 8+、Spring Boot 2.0/2.1
* 1.3.x vesrion : MyBatis 3.4+、Java 6+、Spring Boot 1.5

#### 현재까지 `2.1.x 과 1.3.x 을 많이 사용한다.`

#### application.properties 설정

```properties
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
```

#### application.yml

```yaml
spring:
    datasource:
        driver-class-name: com.mysql.cj.jdbc.Driver
        password: ''
        url: jdbc:mysql://localhost:3306/test
        username: root
```

#### 테이블 생성

```sql
CREATE TABLE `User` (
  `id` bigint NOT NULL AUTO_INCREMENT,
  `name` varchar(100) COLLATE utf8mb4_general_ci DEFAULT NULL,
  `age` int DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci
```

#### User 도메인 생성

```java
@Data
@NoArgsConstructor
public class User {

    private Long id;

    private String name;
    private Integer age;

    public User(String name, Integer age) {
        this.name = name;
        this.age = age;
    }
}
```

#### Mapper interface 작성

```java
@Mapper
public interface UserMapper {

    @Select("SELECT * FROM USER WHERE NAME = #{name}")
    User findByName(@Param("name") String name);

    @Insert("INSERT INTO USER(NAME, AGE) VALUES(#{name}, #{age})")
    int insert(@Param("name") String name, @Param("age") Integer age);

}
```

```java
@Slf4j
@RunWith(SpringRunner.class)
@SpringBootTest
public class MybatisDemoApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Test
    @Rollback
    public void test() throws Exception {
        userMapper.insert("AAA", 20);
        User u = userMapper.findByName("AAA");
        Assert.assertEquals(20, u.getAge().intValue());
    }

}
```

#### @Param  <a href="#shi-yong-param" id="shi-yong-param"></a>

```java
@Insert("INSERT INTO USER(NAME, AGE) VALUES(#{name}, #{age})")
int insert(@Param("name") String name, @Param("age") Integer age);
```

#### Map <a href="#shi-yong-map" id="shi-yong-map"></a>

```java
@Insert("INSERT INTO USER(NAME, AGE) VALUES(#{name,jdbcType=VARCHAR}, #{age,jdbcType=INTEGER})")
int insertByMap(Map<String, Object> map);
```

**Object**

```java
@Insert("INSERT INTO USER(NAME, AGE) VALUES(#{name}, #{age})")
int insertByUser(User user);
```

**C,R,U,D mapper interface 작성**

```java
public interface UserMapper {

    @Select("SELECT * FROM user WHERE name = #{name}")
    User findByName(@Param("name") String name);

    @Insert("INSERT INTO user(name, age) VALUES(#{name}, #{age})")
    int insert(@Param("name") String name, @Param("age") Integer age);

    @Update("UPDATE user SET age=#{age} WHERE name=#{name}")
    void update(User user);

    @Delete("DELETE FROM user WHERE id =#{id}")
    void delete(Long id);
}
```

#### 테스트 코드 작성

```java
@Transactional
@RunWith(SpringRunner.class)
@SpringBootTest
public class MybatisDemoApplicationTests {

	@Autowired
	private UserMapper userMapper;

	@Test
	@Rollback
	public void testUserMapper() throws Exception {
		// insert 후 select 하여 검증
		userMapper.insert("AAA", 20);
		User u = userMapper.findByName("AAA");
		Assert.assertEquals(20, u.getAge().intValue());
		// update 후 select 하여 검증
		u.setAge(30);
		userMapper.update(u);
		u = userMapper.findByName("AAA");
		Assert.assertEquals(30, u.getAge().intValue());
		// 데이터 삭제 및 select 검증
		userMapper.delete(u.getId());
		u = userMapper.findByName("AAA");
		Assert.assertEquals(null, u);
	}
}
```

Result 객체 바인딩

```java
@Results({
    @Result(property = "name", column = "name"),
    @Result(property = "age", column = "age")
})
@Select("SELECT name, age FROM user")
List<User> findAll();
```

테스트 코드 작성

```java
@Test
@Rollback
public void testUserMapper() throws Exception {
	List<User> userList = userMapper.findAll();
	for(User user : userList) {
		Assert.assertEquals(null, user.getId());
		Assert.assertNotEquals(null, user.getName());
	}
}
```

끝!