MyBatis系列目录--5. MyBatis一级缓存和二级缓存(redis实现)
2017-07-10 11:15 dogdogwang 阅读(453) 评论(0) 编辑 收藏 举报0. 相关知识:
查询缓存:绝大数系统主要是读多写少。
缓存作用:减轻数据库压力,提供访问速度。
1. 一级缓存测试用例
(1) 默认开启,不需要有什么配置
(2) 示意图
(3) 测试代码
- package com.sohu.tv.cache;
- import org.apache.ibatis.session.SqlSession;
- import org.junit.After;
- import org.junit.Before;
- import org.junit.Test;
- import com.sohu.tv.bean.Player;
- import com.sohu.tv.mapper.PlayerDao;
- import com.sohu.tv.test.mapper.BaseTest;
- /**
- * 一级缓存测试
- *
- * @author leifu
- * @Date 2015-8-3
- * @Time 下午9:51:00
- */
- public class FirstCacheTest extends BaseTest {
- private SqlSession sqlSession;
- private SqlSession sqlSessionAnother;
- @Before
- public void before() {
- sqlSession = sessionFactory.openSession(false);
- sqlSessionAnother = sessionFactory.openSession(false);
- }
- @After
- public void after() {
- sqlSession.close();
- sqlSessionAnother.close();
- }
- @Test
- public void test1() throws Exception {
- PlayerDao playerDao = sqlSession.getMapper(PlayerDao.class);
- Player player = playerDao.getPlayerById(1);
- System.out.println(player);
- playerDao = sqlSession.getMapper(PlayerDao.class);
- player = playerDao.getPlayerById(1);
- System.out.println(player);
- playerDao = sqlSessionAnother.getMapper(PlayerDao.class);
- player = playerDao.getPlayerById(1);
- System.out.println(player);
- }
- @Test
- public void test2() throws Exception {
- PlayerDao playerDao = sqlSession.getMapper(PlayerDao.class);
- Player player = playerDao.getPlayerById(1);
- System.out.println(player);
- //1. session清除或者提交
- // sqlSession1.commit();
- // sqlSession.clearCache();
- //2. 增删改查
- // playerDao.savePlayer(new Player(-1, "abcd", 13));
- // playerDao.updatePlayer(new Player(4, "abcd", 13));
- playerDao.deletePlayer(4);
- player = playerDao.getPlayerById(1);
- System.out.println(player);
- }
- }
2、二级缓存(自带 PerpetualCache)
(0) 示意图
(1) 二级缓存需要开启
总配置文件中,二级缓存也是开启的,不需要设置
- <setting name="cacheEnabled" value="true"/>
mapper级别的cache需要开启,在对应的mapper.xml写入
- <!--开启本mapper的二级缓存-->
- <cache/>
(2) 实体类在二级缓存中需要进行序列化,所以所有实体类需要实现Serializable
(3) 示例:
- package com.sohu.tv.cache;
- import org.apache.ibatis.session.SqlSession;
- import org.junit.After;
- import org.junit.Before;
- import org.junit.Test;
- import com.sohu.tv.bean.Player;
- import com.sohu.tv.mapper.PlayerDao;
- import com.sohu.tv.test.mapper.BaseTest;
- /**
- * 二级缓存测试
- *
- * @author leifu
- * @Date 2015-8-3
- * @Time 下午10:10:34
- */
- public class SecondCacheTest extends BaseTest {
- private SqlSession sqlSession1 = sessionFactory.openSession();
- private SqlSession sqlSession2 = sessionFactory.openSession();
- private SqlSession sqlSession3 = sessionFactory.openSession();
- private PlayerDao playerDao1;
- private PlayerDao playerDao2;
- private PlayerDao playerDao3;
- @Before
- public void before() {
- sqlSession1 = sessionFactory.openSession(false);
- sqlSession2 = sessionFactory.openSession(false);
- sqlSession3 = sessionFactory.openSession(false);
- playerDao1 = sqlSession1.getMapper(PlayerDao.class);
- playerDao2 = sqlSession2.getMapper(PlayerDao.class);
- playerDao3 = sqlSession3.getMapper(PlayerDao.class);
- }
- @After
- public void after() {
- sqlSession1.close();
- sqlSession2.close();
- sqlSession3.close();
- }
- @Test
- public void test1() throws Exception {
- int targetId = 1;
- //session1 查询并提交
- Player player1 = playerDao1.getPlayerById(targetId);
- System.out.println("player1: " + player1);
- sqlSession1.commit();
- //session2 命中后,更新并提交清空缓存
- Player player2 = playerDao2.getPlayerById(targetId);
- System.out.println("player2: " + player2);
- player2.setAge(15);
- playerDao2.update(player2);
- sqlSession2.commit();
- //session3 不命中
- Player player3 = playerDao3.getPlayerById(targetId);
- System.out.println("player3: " + player3);
- }
- @Test
- public void test2() throws Exception {
- int one = 1;
- int two = 2;
- //session1 查询并提交
- Player player1 = playerDao1.getPlayerById(one);
- playerDao1.getPlayerById(two);
- System.out.println("player1: " + player1);
- sqlSession1.commit();
- //session2 命中后,更新并提交清空缓存
- Player player2 = playerDao2.getPlayerById(one);
- System.out.println("player2: " + player2);
- player2.setAge(15);
- playerDao2.updatePlayer(player2);
- sqlSession2.commit();
- //session3 不命中
- Player player3 = playerDao3.getPlayerById(two);
- System.out.println("player3: " + player3);
- }
- }
(4) 重要日志:
3、二级缓存(Redis版)
(1) redis使用一个简单的单点实例作为数据源:
引入jedis pom依赖:
- <jedis.version>2.8.0</jedis.version>
- <protostuff.version>1.0.8</protostuff.version>
- <dependency>
- <groupId>redis.clients</groupId>
- <artifactId>jedis</artifactId>
- <version>${jedis.version}</version>
- </dependency>
- <dependency>
- <groupId>com.dyuproject.protostuff</groupId>
- <artifactId>protostuff-runtime</artifactId>
- <version>${protostuff.version}</version>
- </dependency>
- <dependency>
- <groupId>com.dyuproject.protostuff</groupId>
- <artifactId>protostuff-core</artifactId>
- <version>${protostuff.version}</version>
- </dependency>
jedis获取工具(使用jedispool)
- package com.sohu.tv.redis;
- import org.apache.commons.pool2.impl.GenericObjectPoolConfig;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
- import redis.clients.jedis.JedisPool;
- /**
- * jedisPool获取工具
- *
- * @author leifu
- * @Date 2015年8月4日
- * @Time 上午9:01:45
- */
- public class RedisStandAloneUtil {
- private final static Logger logger = LoggerFactory.getLogger(RedisStandAloneUtil.class);
- /**
- * jedis连接池
- */
- private static JedisPool jedisPool;
- /**
- * redis-host
- */
- private final static String REDIS_HOST = "10.10.xx.xx";
- /**
- * redis-port
- */
- private final static int REDIS_PORT = 6384;
- static {
- try {
- jedisPool = new JedisPool(new GenericObjectPoolConfig(), REDIS_HOST, REDIS_PORT);
- } catch (Exception e) {
- logger.error(e.getMessage(), e);
- }
- }
- public static JedisPool getJedisPool() {
- return jedisPool;
- }
- public static void main(String[] args) {
- System.out.println(RedisStandAloneUtil.getJedisPool().getResource().info());
- }
- }
(2) 如果自己实现mybatis的二级缓存,需要实现org.apache.ibatis.cache.Cache接口,已经实现的有如下:
序列化相关工具代码:
- package com.sohu.tv.redis.serializable;
- import com.dyuproject.protostuff.LinkedBuffer;
- import com.dyuproject.protostuff.ProtostuffIOUtil;
- import com.dyuproject.protostuff.Schema;
- import com.dyuproject.protostuff.runtime.RuntimeSchema;
- import java.util.concurrent.ConcurrentHashMap;
- public class ProtostuffSerializer {
- private static ConcurrentHashMap<Class<?>, Schema<?>> cachedSchema = new ConcurrentHashMap<Class<?>, Schema<?>>();
- public <T> byte[] serialize(final T source) {
- VO<T> vo = new VO<T>(source);
- final LinkedBuffer buffer = LinkedBuffer.allocate(LinkedBuffer.DEFAULT_BUFFER_SIZE);
- try {
- final Schema<VO> schema = getSchema(VO.class);
- return serializeInternal(vo, schema, buffer);
- } catch (final Exception e) {
- throw new IllegalStateException(e.getMessage(), e);
- } finally {
- buffer.clear();
- }
- }
- public <T> T deserialize(final byte[] bytes) {
- try {
- Schema<VO> schema = getSchema(VO.class);
- VO vo = deserializeInternal(bytes, schema.newMessage(), schema);
- if (vo != null && vo.getValue() != null) {
- return (T) vo.getValue();
- }
- } catch (final Exception e) {
- throw new IllegalStateException(e.getMessage(), e);
- }
- return null;
- }
- private <T> byte[] serializeInternal(final T source, final Schema<T> schema, final LinkedBuffer buffer) {
- return ProtostuffIOUtil.toByteArray(source, schema, buffer);
- }
- private <T> T deserializeInternal(final byte[] bytes, final T result, final Schema<T> schema) {
- ProtostuffIOUtil.mergeFrom(bytes, result, schema);
- return result;
- }
- private static <T> Schema<T> getSchema(Class<T> clazz) {
- @SuppressWarnings("unchecked")
- Schema<T> schema = (Schema<T>) cachedSchema.get(clazz);
- if (schema == null) {
- schema = RuntimeSchema.createFrom(clazz);
- cachedSchema.put(clazz, schema);
- }
- return schema;
- }
- }
- package com.sohu.tv.redis.serializable;
- import java.io.Serializable;
- public class VO<T> implements Serializable {
- private T value;
- public VO(T value) {
- this.value = value;
- }
- public VO() {
- }
- public T getValue() {
- return value;
- }
- @Override
- public String toString() {
- return "VO{" +
- "value=" + value +
- '}';
- }
- }
Redis需要自己来实现,代码如下:
- package com.sohu.tv.redis;
- import java.util.concurrent.locks.ReadWriteLock;
- import java.util.concurrent.locks.ReentrantReadWriteLock;
- import org.apache.ibatis.cache.Cache;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
- import redis.clients.jedis.Jedis;
- import redis.clients.jedis.serializable.ProtostuffSerializer;
- /**
- * mybatis redis实现
- *
- * @author leifu
- * @Date 2015年8月4日
- * @Time 上午9:12:37
- */
- public class MybatisRedisCache implements Cache {
- private static Logger logger = LoggerFactory.getLogger(MybatisRedisCache.class);
- private String id;
- private final ReadWriteLock readWriteLock = new ReentrantReadWriteLock();
- private final ProtostuffSerializer protostuffSerializer = new ProtostuffSerializer();
- public MybatisRedisCache(final String id) {
- if (logger.isInfoEnabled()) {
- logger.info("============ MybatisRedisCache id {} ============", id);
- }
- if (id == null) {
- throw new IllegalArgumentException("Cache instances require an ID");
- }
- this.id = id;
- }
- @Override
- public String getId() {
- return this.id;
- }
- @Override
- public int getSize() {
- Jedis jedis = null;
- int size = -1;
- try {
- jedis = RedisStandAloneUtil.getJedisPool().getResource();
- size = Integer.valueOf(jedis.dbSize().toString());
- } catch (Exception e) {
- logger.error(e.getMessage(), e);
- } finally {
- if (jedis != null) {
- jedis.close();
- }
- }
- return size;
- }
- @Override
- public void putObject(Object key, Object value) {
- if (logger.isInfoEnabled()) {
- logger.info("============ putObject key: {}, value: {} ============", key, value);
- }
- Jedis jedis = null;
- try {
- jedis = RedisStandAloneUtil.getJedisPool().getResource();
- byte[] byteKey = protostuffSerializer.serialize(key);
- byte[] byteValue = protostuffSerializer.serialize(value);
- jedis.set(byteKey, byteValue);
- } catch (Exception e) {
- logger.error(e.getMessage(), e);
- } finally {
- if (jedis != null) {
- jedis.close();
- }
- }
- }
- @Override
- public Object getObject(Object key) {
- if (logger.isInfoEnabled()) {
- logger.info("============ getObject key: {}============", key);
- }
- Object object = null;
- Jedis jedis = null;
- try {
- jedis = RedisStandAloneUtil.getJedisPool().getResource();
- byte[] bytes = jedis.get(protostuffSerializer.serialize(key));
- if (bytes != null) {
- object = protostuffSerializer.deserialize(bytes);
- }
- } catch (Exception e) {
- logger.error(e.getMessage(), e);
- } finally {
- if (jedis != null) {
- jedis.close();
- }
- }
- return object;
- }
- @Override
- public Object removeObject(Object key) {
- if (logger.isInfoEnabled()) {
- logger.info("============ removeObject key: {}============", key);
- }
- String result = "success";
- Jedis jedis = null;
- try {
- jedis = RedisStandAloneUtil.getJedisPool().getResource();
- jedis.del(String.valueOf(key));
- } catch (Exception e) {
- logger.error(e.getMessage(), e);
- } finally {
- if (jedis != null) {
- jedis.close();
- }
- }
- return result;
- }
- @Override
- public void clear() {
- if (logger.isInfoEnabled()) {
- logger.info("============ start clear cache ============");
- }
- String result = "fail";
- Jedis jedis = null;
- try {
- jedis = RedisStandAloneUtil.getJedisPool().getResource();
- result = jedis.flushAll();
- } catch (Exception e) {
- logger.error(e.getMessage(), e);
- } finally {
- if (jedis != null) {
- jedis.close();
- }
- }
- if (logger.isInfoEnabled()) {
- logger.info("============ end clear cache result is {}============", result);
- }
- }
- @Override
- public ReadWriteLock getReadWriteLock() {
- return readWriteLock;
- }
- }
(3) mapper配置中加入自定义redis二级缓存:
- <cache type="com.sohu.tv.redis.MybatisRedisCache"/>