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本文主要研究一下jedis的return行为
spring-data-redis
RedisTemplate
org/springframework/data/redis/core/RedisTemplate.java
代码语言：javascript复制 @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方法先通过RedisConnectionUtils.getConnection获取连接，最后通过RedisConnectionUtils.releaseConnection来归还连接
RedisConnectionUtils
org/springframework/data/redis/core/RedisConnectionUtils.java
代码语言：javascript复制 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方法主要是处理了事务相关的操作，最后执行doCloseConnection，它最后执行的是connection.close()
connection.close()
org/springframework/data/redis/connection/jedis/JedisConnection.java
代码语言：javascript复制 @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方法针对使用连接池的会执行jedis.close，否则执行jedis.quit
jedis.close()
redis/clients/jedis/Jedis.java
代码语言：javascript复制 @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方法会先判断isBroken(
取的redis.clients.jedis.Connection.broken属性)，如果是则执行returnBrokenResource，否则执行returnResource
pool
redis/clients/jedis/util/Pool.java
代码语言：javascript复制 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
代码语言：javascript复制 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方法执行的是destroy方法，该方法会回调factory.destroyObject
destroyObject
redis/clients/jedis/JedisFactory.java
代码语言：javascript复制 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方法则执行jedis.close()关闭client连接
returnObject
org/apache/commons/pool2/impl/GenericObjectPool.java
代码语言：javascript复制 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方法，之后执行factory.passivateObject§，最后根据maxIdle的参数来判断，超出的则执行destroy，否则根据是否Lifo放回到连接池(
idleObjects)中
小结
spring-data-redis的return主要是执行connection的close方法，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方法执行的是destroy方法，该方法会回调factory.destroyObject方法，即执行jedis.close()关闭client连接
- returnObject针对testOnReturn的会执行validateObject方法，之后执行factory.passivateObject§，最后根据maxIdle的参数来判断，超出的则执行destroy，否则根据是否Lifo放回到连接池(
idleObjects)中 - 也就说假设获取连接之后，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，因而归还的时候会触发returnBrokenResource从而关闭坏掉的连接，间接实现
testOnReturn的效果 - 如果在获取连接的时候，redis挂了，但是连接池仍然有连接，若没有testOnBorrow则返回然后使用，但是使用的时候会报错，即redis.clients.jedis.Connection会标记broken为true，同时抛出JedisConnectionException，归还的时候直接销毁；若有testOnBorrow则validate的时候能验证出来连接有问题，则会执行destory然后继续循环获取连接池的连接，直到连接池连接没有了；若获取连接的时候连接池没有空闲连接了，则走create的逻辑，这个时候create直接抛出redis.clients.jedis.exceptions.JedisConnectionException: Failed to create socket.
