mybatis之缓存

1.com.dao(shopMapper)

public interface ShopMapper {
	
	List<Shop> cache();
	
	void delete();
}

<mapper namespace="com.dao.ShopMapper">
	<!-- 开启二级缓存 -->
	<cache/>

	<select id="cache" resultType="shop">
		select * from shop
	</select>
	
	<delete id="delete">
		delete from shop where shopid=100
	</delete>
</mapper>

2.com.pojo(cshop)

public class Shop implements Serializable {

	private static final long serialVersionUID = 1L;

	private String shopId;
	
	private String shopName;
	
	private String shopAddress;
	
	private String contact;
	
	public String getShopId() {
		return shopId;
	}

	public void setShopId(String shopId) {
		this.shopId = shopId;
	}

	public String getShopName() {
		return shopName;
	}

	public void setShopName(String shopName) {
		this.shopName = shopName;
	}

	public String getShopAddress() {
		return shopAddress;
	}

	public void setShopAddress(String shopAddress) {
		this.shopAddress = shopAddress;
	}

	public String getContact() {
		return contact;
	}

	public void setContact(String contact) {
		this.contact = contact;
	}
}

3.com.service(ShopService)

public class ShopService {

	// 测试一级缓存，必须为同一个SqlSession对象
	public List<Shop> cache1() {
		
		SqlSession session = null;
		
		try {
			session = MyBatisUtils.getSqlSession();
			ShopMapper mapper = session.getMapper(ShopMapper.class);
			
			// 首次查询发出sql
			List<Shop> list = mapper.cache();
			
			session.commit(); // 执行commit或rollback操作将会清空一级缓存
			
			// 若未执行commit或rollback操作将不会发出sql，从一级缓存中查找数据，否则发出
			list = mapper.cache();
			
			return list;
		} finally {
			MyBatisUtils.close(session);
		}
	}
	
	// 测试二级缓存，必须为同一个Mapper对象
	public List<Shop> cache2() {
		
		SqlSession session = null;
		
		try {
			session = MyBatisUtils.getSqlSession();
			ShopMapper mapper = session.getMapper(ShopMapper.class);
			
			return mapper.cache();
		} finally {
			MyBatisUtils.close(session);
		}
	}
	
	public void clearCache() {
		
		SqlSession session = null;
		
		try {
			session = MyBatisUtils.getSqlSession();
			ShopMapper mapper = session.getMapper(ShopMapper.class);
			mapper.delete();
			session.commit(); // 执行commit操作将会清空二级缓存
		} finally {
			MyBatisUtils.close(session);
		}
	}
}

4.com.test（TestCrud）

public class TestCrud {

	private ShopService service = new ShopService();
	
	@Test
	public void testCache1() {
		
		List<Shop> list = service.cache1();
		
		for(Shop shop : list) {
			String shopId = shop.getShopId();
			String shopName = shop.getShopName();
			String shopAddress = shop.getShopAddress();
			String contact = shop.getContact();
			
			System.out.println(shopId + "-" + shopName + "-" + shopAddress + "-" + contact);
		}
	}
	
	@Test
	public void testCache2() {
		
		// 首次查询发出sql
		List<Shop> list = service.cache2();
		
		// 执行commit操作将会清空二级缓存
		service.clearCache();
		
		// 若未执行commit操作将不会发出sql，从二级缓存中查找数据，否则发出
		list = service.cache2();
		
		for(Shop shop : list) {
			String shopId = shop.getShopId();
			String shopName = shop.getShopName();
			String shopAddress = shop.getShopAddress();
			String contact = shop.getContact();
			
			System.out.println(shopId + "-" + shopName + "-" + shopAddress + "-" + contact);
		}
	}
}

5.com.util(MyBatisUtil)

public final class MyBatisUtil {

	private static SqlSessionFactory factory = buildSqlSessionFactory();
	
	private MyBatisUtil() {}
	
	private static final SqlSessionFactory buildSqlSessionFactory() {
		
		String resource = "resources/mybatis-config.xml";
		
		try {
			InputStream inputStream = Resources.getResourceAsStream(resource);
			return new SqlSessionFactoryBuilder().build(inputStream);
		} catch (Exception e) {
			e.printStackTrace();
		}
		
		return null;
	}
	
	public static final SqlSession getSqlSession() {
		
		return factory.openSession();
	}
	
	public static final void close(SqlSession sqlSession) {
		
		if(sqlSession != null) {
			sqlSession.close();
		}
	}
}

6.resources(db.properties+mybatis-config.xml)

jdbc.driver=oracle.jdbc.OracleDriver
jdbc.url=jdbc:oracle:thin:@localhost:1521:orcl
jdbc.username=meitao
jdbc.password=123
___________________________________________
<configuration>
	<!-- 外部属性文件 -->
	<properties resource="resources/db.properties"/>

	<settings>
		<!-- 控制台显示sql语句(开发使用) -->
		<setting name="logImpl" value="STDOUT_LOGGING"/>
	</settings>
	
	<typeAliases>
  		<package name="com.pojo"/>
	</typeAliases>

	<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>
		<!-- <mapper resource="resources/ShopMapper.xml"/> -->
		
		<!-- 注册指定包中的所有映射器接口(推荐) -->
		<package name="com.dao"/>
	</mappers>
</configuration>