MyBatis 注解开发

1. 环境搭建

1.1. 依赖

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.6</version>
        <scope>provided</scope>
    </dependency>
    <!-- log4j 用于mybatis输出日志 -->
    <dependency>
        <groupId>log4j</groupId>
        <artifactId>log4j</artifactId>
        <version>1.2.17</version>
    </dependency>
    <!-- mybatis -->
    <dependency>
        <groupId>org.mybatis</groupId>
        <artifactId>mybatis</artifactId>
        <version>3.5.1</version>
    </dependency>
    <!-- mysql -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
        <version>5.1.32</version>
    </dependency>
</dependencies>

1.2. log4j.properties

用于打印MyBatis日志

# Global logging configuration
log4j.rootLogger=DEBUG, stdout
# Console output...
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n

1.3. jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test?useSSL=true
jdbc.username=root
jdbc.password=123456

1.4. MyBatis全局配置文件mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>

    <properties resource="jdbc.properties"/>

    <settings>
        <setting name="mapUnderscoreToCamelCase" value="true"/>
    </settings>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url"
                          value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <package name="demo.mybatis.mapper"/>
    </mappers>
</configuration>

1.5. 实体类

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Person {
    private Long personId;
    private String firstName;
    private Date birthday;
}

1.6. Mapper

public interface PersonMapper {
    @Select("SELECT * FROM person WHERE person_id = #{personId}")
    Person findById(Long personId);

    @Select("SELECT * FROM person")
    List<Person> listPerson();

    @Select("SELECT * FROM person WHERE person_id = #{personId} AND first_name = #{firstName}")
    Person findByIdAndFirstName(@Param("personId") Long personId, @Param("firstName") String firstName);

    @Delete("DELETE FROM person WHERE person_id = #{personId}")
    int deleteById(Long personId);

    @Update("UPDATE person SET first_name = #{firstName}, birthday = #{birthday} " +
            "WHERE person_id = #{personId}")
    int updateById(Person person);

    @Update("INSERT INTO person (first_name, birthday) VALUES (#{firstName}, #{birthday})")
    int insert(Person perosn);
}

1.7. 测试

public class MybatisTest {
    SqlSessionFactory sqlSessionFactory = null;
    SqlSession sqlSession = null;

    @Before
    public void setup() throws IOException {
        InputStream in = Resources.getResourceAsStream("mybatis-config.xml");
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        sqlSession = sqlSessionFactory.openSession();
    }

    @After
    public void teardown() {
        if (sqlSession != null) {
            sqlSession.close();
        }
    }

    @Test
    public void findById() throws IOException {
        PersonMapper mapper = sqlSession.getMapper(PersonMapper.class);
        Person person = mapper.findById(32L);
        System.out.println(person);
    }

    @Test
    public void listPerson() {
        PersonMapper mapper = sqlSession.getMapper(PersonMapper.class);
        List<Person> list = mapper.listPerson();
        list.forEach(System.out::println);
    }

    @Test
    public void findByIdAndFirstName() throws IOException {
        PersonMapper mapper = sqlSession.getMapper(PersonMapper.class);
        Person person = mapper.findByIdAndFirstName(32L, "李四");
        System.out.println(person);
    }
    
    @Test
    public void deleteById() throws IOException {
        PersonMapper mapper = sqlSession.getMapper(PersonMapper.class);
        mapper.deleteById(3L);
        sqlSession.commit();
    }

    @Test
    public void insert() throws IOException {
        PersonMapper mapper = sqlSession.getMapper(PersonMapper.class);
        Person person = new Person(null, "张三", new Date());
        mapper.insert(person);
        System.out.println(person);
        sqlSession.commit();
    }

    @Test
    public void updateById() throws IOException {
        PersonMapper mapper = sqlSession.getMapper(PersonMapper.class);
        Person person = new Person(32L, "李四", new Date());
        mapper.updateById(person);
        sqlSession.commit();
    }
}