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本文次要钻研一下jedis的return行为
spring-data-redis
RedisTemplate
org/springframework/data/redis/core/RedisTemplate.java
@Nullable public <T> T execute(RedisCallback<T> action, boolean exposeConnection, boolean pipeline) { Assert.isTrue(initialized, "template not initialized; call afterPropertiesSet() before using it"); Assert.notNull(action, "Callback object must not be null"); RedisConnectionFactory factory = getRequiredConnectionFactory(); RedisConnection conn = RedisConnectionUtils.getConnection(factory, enableTransactionSupport); try { boolean existingConnection = TransactionSynchronizationManager.hasResource(factory); RedisConnection connToUse = preProcessConnection(conn, existingConnection); boolean pipelineStatus = connToUse.isPipelined(); if (pipeline && !pipelineStatus) { connToUse.openPipeline(); } RedisConnection connToExpose = (exposeConnection ? connToUse : createRedisConnectionProxy(connToUse)); T result = action.doInRedis(connToExpose); // close pipeline if (pipeline && !pipelineStatus) { connToUse.closePipeline(); } return postProcessResult(result, connToUse, existingConnection); } finally { RedisConnectionUtils.releaseConnection(conn, factory, enableTransactionSupport); } }RedisTemplate的execute办法先通过RedisConnectionUtils.getConnection获取连贯，最初通过RedisConnectionUtils.releaseConnection来偿还连贯
RedisConnectionUtils
org/springframework/data/redis/core/RedisConnectionUtils.java
public static void releaseConnection(@Nullable RedisConnection conn, RedisConnectionFactory factory, boolean transactionSupport) { releaseConnection(conn, factory); } public static void releaseConnection(@Nullable RedisConnection conn, RedisConnectionFactory factory) { if (conn == null) { return; } RedisConnectionHolder conHolder = (RedisConnectionHolder) TransactionSynchronizationManager.getResource(factory); if (conHolder != null) { if (conHolder.isTransactionActive()) { if (connectionEquals(conHolder, conn)) { if (log.isDebugEnabled()) { log.debug("RedisConnection will be closed when transaction finished."); } // It's the transactional Connection: Don't close it. conHolder.released(); } return; } // release transactional/read-only and non-transactional/non-bound connections. // transactional connections for read-only transactions get no synchronizer registered unbindConnection(factory); return; } doCloseConnection(conn); } private static void doCloseConnection(@Nullable RedisConnection connection) { if (connection == null) { return; } if (log.isDebugEnabled()) { log.debug("Closing Redis Connection."); } try { connection.close(); } catch (DataAccessException ex) { log.debug("Could not close Redis Connection", ex); } catch (Throwable ex) { log.debug("Unexpected exception on closing Redis Connection", ex); } }releaseConnection办法次要是解决了事务相干的操作，最初执行doCloseConnection，它最初执行的是connection.close()
connection.close()
org/springframework/data/redis/connection/jedis/JedisConnection.java
@Override public void close() throws DataAccessException { super.close(); JedisSubscription subscription = this.subscription; try { if (subscription != null) { subscription.close(); } } catch (Exception ex) { LOGGER.debug("Cannot terminate subscription", ex); } finally { this.subscription = null; } // return the connection to the pool if (pool != null) { jedis.close(); return; } // else close the connection normally (doing the try/catch dance) try { jedis.quit(); } catch (Exception ex) { LOGGER.debug("Failed to QUIT during close", ex); } try { jedis.disconnect(); } catch (Exception ex) { LOGGER.debug("Failed to disconnect during close", ex); } }connection的close办法针对应用连接池的会执行jedis.close，否则执行jedis.quit
jedis.close()
redis/clients/jedis/Jedis.java
@Override public void close() { if (dataSource != null) { JedisPoolAbstract pool = this.dataSource; this.dataSource = null; if (isBroken()) { pool.returnBrokenResource(this); } else { pool.returnResource(this); } } else { super.close(); } }jedis的close办法会先判断isBroken(取的redis.clients.jedis.Connection.broken属性)，如果是则执行returnBrokenResource，否则执行returnResourcepool
redis/clients/jedis/util/Pool.java
public void returnBrokenResource(final T resource) { if (resource != null) { returnBrokenResourceObject(resource); } } public void returnResource(final T resource) { if (resource != null) { returnResourceObject(resource); } } protected void returnBrokenResourceObject(final T resource) { try { internalPool.invalidateObject(resource); } catch (Exception e) { throw new JedisException("Could not return the broken resource to the pool", e); } } protected void returnResourceObject(final T resource) { try { internalPool.returnObject(resource); } catch (RuntimeException e) { throw new JedisException("Could not return the resource to the pool", e); } }returnBrokenResource执行的是internalPool.invalidateObject(resource)，而returnResourceObject执行的是internalPool.returnObject(resource)
invalidateObject
org/apache/commons/pool2/impl/GenericObjectPool.java
public void invalidateObject(final T obj, final DestroyMode destroyMode) throws Exception { final PooledObject<T> p = getPooledObject(obj); if (p == null) { if (isAbandonedConfig()) { return; } throw new IllegalStateException( "Invalidated object not currently part of this pool"); } synchronized (p) { if (p.getState() != PooledObjectState.INVALID) { destroy(p, destroyMode); } } ensureIdle(1, false); } private void destroy(final PooledObject<T> toDestroy, final DestroyMode destroyMode) throws Exception { toDestroy.invalidate(); idleObjects.remove(toDestroy); allObjects.remove(new IdentityWrapper<>(toDestroy.getObject())); try { factory.destroyObject(toDestroy, destroyMode); } finally { destroyedCount.incrementAndGet(); createCount.decrementAndGet(); } }invalidateObject办法执行的是destroy办法，该办法会回调factory.destroyObject
destroyObject
redis/clients/jedis/JedisFactory.java
public void destroyObject(PooledObject<Jedis> pooledJedis) throws Exception { final BinaryJedis jedis = pooledJedis.getObject(); if (jedis.isConnected()) { try { // need a proper test, probably with mock if (!jedis.isBroken()) { jedis.quit(); } } catch (RuntimeException e) { logger.warn("Error while QUIT", e); } try { jedis.close(); } catch (RuntimeException e) { logger.warn("Error while close", e); } } }destroyObject办法则执行jedis.close()敞开client连贯
returnObject
org/apache/commons/pool2/impl/GenericObjectPool.java
public void returnObject(final T obj) { final PooledObject<T> p = getPooledObject(obj); if (p == null) { if (!isAbandonedConfig()) { throw new IllegalStateException( "Returned object not currently part of this pool"); } return; // Object was abandoned and removed } markReturningState(p); final Duration activeTime = p.getActiveDuration(); if (getTestOnReturn() && !factory.validateObject(p)) { try { destroy(p, DestroyMode.NORMAL); } catch (final Exception e) { swallowException(e); } try { ensureIdle(1, false); } catch (final Exception e) { swallowException(e); } updateStatsReturn(activeTime); return; } try { factory.passivateObject(p); } catch (final Exception e1) { swallowException(e1); try { destroy(p, DestroyMode.NORMAL); } catch (final Exception e) { swallowException(e); } try { ensureIdle(1, false); } catch (final Exception e) { swallowException(e); } updateStatsReturn(activeTime); return; } if (!p.deallocate()) { throw new IllegalStateException( "Object has already been returned to this pool or is invalid"); } final int maxIdleSave = getMaxIdle(); if (isClosed() || maxIdleSave > -1 && maxIdleSave <= idleObjects.size()) { try { destroy(p, DestroyMode.NORMAL); } catch (final Exception e) { swallowException(e); } try { ensureIdle(1, false); } catch (final Exception e) { swallowException(e); } } else { if (getLifo()) { idleObjects.addFirst(p); } else { idleObjects.addLast(p); } if (isClosed()) { // Pool closed while object was being added to idle objects. // Make sure the returned object is destroyed rather than left // in the idle object pool (which would effectively be a leak) clear(); } } updateStatsReturn(activeTime); }returnObject针对testOnReturn的会执行validateObject办法，之后执行factory.passivateObject(p)，最初依据maxIdle的参数来判断，超出的则执行destroy，否则依据是否Lifo放回到连接池(idleObjects)中小结
spring-data-redis的return次要是执行connection的close办法，对应到jedis就是jedis.close()，它会先判断isBroken(取的redis.clients.jedis.Connection.broken属性)，如果是则执行returnBrokenResource，否则执行returnResource。
- returnBrokenResource执行的是internalPool.invalidateObject(resource)，invalidateObject办法执行的是destroy办法，该办法会回调factory.destroyObject办法，即执行jedis.close()敞开client连贯
- returnObject针对testOnReturn的会执行validateObject办法，之后执行factory.passivateObject(p)，最初依据maxIdle的参数来判断，超出的则执行destroy，否则依据是否Lifo放回到连接池(
idleObjects)中 - 也就说假如获取连贯之后，执行的时候redis挂了，redis.clients.jedis.Connection会标记broken为true，同时抛出JedisConnectionException；而RedisTemplate是在finally中进行releaseConnection，因此偿还的时候会触发returnBrokenResource从而敞开坏掉的连贯，间接实现
testOnReturn的成果 - 如果在获取连贯的时候，redis挂了，然而连接池依然有连贯，若没有testOnBorrow则返回而后应用，然而应用的时候会报错，即redis.clients.jedis.Connection会标记broken为true，同时抛出JedisConnectionException，偿还的时候间接销毁；若有testOnBorrow则validate的时候能验证进去连贯有问题，则会执行destory而后持续循环获取连接池的连贯，直到连接池连贯没有了；若获取连贯的时候连接池没有闲暇连贯了，则走create的逻辑，这个时候create间接抛出redis.clients.jedis.exceptions.JedisConnectionException: Failed to create socket.