02_mybatis的CRUD操作

1、XML 的实现

1.1 定义SQL映射xml文件

<insert id="insertUser" parameterType="cn.imentors.mybatis.test1.User">
	insert into users(name, age) values(#{name}, #{age});
</insert>
<delete id="deleteUser" parameterType="int">
	delete from users where id=#{id}
</delete>
<update id="updateUser" parameterType="cn.imentors.mybatis.test1.User">
	update users set name=#{name},age=#{age} where id=#{id}
</update>

• parameterType="cn.imentors.mybatis.test1.User"，这个参数类型是一个对象，所以占位符必须是对象的属性#{name}
  

1.2 在config.xml 中注册这个映射文件

	<mappers>
		<mapper resource="cn/imentors/mybatis/test1/UserMapper.xml"/>
	</mappers>
</configuration>

1.3 MyBatisUtils

为了后面测试的方便，将conf.xml文件的加载，写成一个工具类

package cn.imentors.mybatis.util;
public class MybatisUtils {
	public static SqlSessionFactory getFactory() {
		String resource = "conf.xml";
		InputStream is = Test.class.getClassLoader().getResourceAsStream(resource);
		SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
		return factory;
	}
}

1.4 测试CRUD操作的XML实现

• add

@Test
	public void testAdd() {
		SqlSessionFactory factory = MybatisUtils.getFactory();
		//默认是手动提交的
		SqlSession session = factory.openSession();
		String statement = "cn.imentors.mybatis.test2.userMapper.insertUser";
		int insert = session.insert(statement , new User(3, "KK", 23));
		//提交
		session.commit();
		session.close();
		System.out.println(insert);
	}

• update

@Test
	public void testUpate() {
		SqlSessionFactory factory = MybatisUtils.getFactory();
		//默认是手动提交的
		SqlSession session = factory.openSession(true);
		
		String statement = "cn.imentors.mybatis.test2.userMapper.updateUser";
		
		int update = session.update(statement, new User(3, "KK444", 25));
		
		session.close();
		System.out.println(update);
	}

• delete

@Test
	public void testDelete() {
		SqlSessionFactory factory = MybatisUtils.getFactory();
		// 默认是手动提交的
		SqlSession session = factory.openSession(true);
		String statement = "cn.imentors.mybatis.test2.userMapper.deleteUser";
		int delete = session.delete(statement, 3);
		session.close();
		System.out.println(delete);
	}

2、注解的实现

2.1 定义SQL映射的接口

public interface UserMapper {
	@Insert("insert into users(name, age) values(#{name}, #{age})")
	public int insertUser(User user);
	@Delete("delete from users where id=#{id}")
	public int deleteUserById(int id);
			
	@Update("update users set name=#{name},age=#{age} where id=#{id}")
	public int updateUser(User user);
	@Select("select * from users where id=#{id}")
	public User getUserById(int id);
	@Select("select * from users")
	public List<User> getAllUser();
}

2.2 在conf.xml中注册这个映射接口

<mapper class="cn.imentors.mybatis.test3.UserMapper"/>

2.3 测试

@Test
	public void testAdd() {
		SqlSessionFactory factory = MybatisUtils.getFactory();
		//默认是手动提交的
		SqlSession session = factory.openSession(true);
		//加载UserMapper接口
		UserMapper mapper = session.getMapper(UserMapper.class);
		int add = mapper.add(new User(4, "SS", 45));
		System.out.println(add);
		
		session.close();
	}

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