我在服务器模式下使用Redis而不是在群集模式下。我有3个Redis Server运行实例，3个从属对应这3个主服务器。我还有3个哨兵，每个都监控所有三个主人。
要连接到我的Sentinels并创建一个游泳池，我正在使用ShardedJedisSentinelPool。现在，我从这个池中获取连接的类看起来像这样
public class RedisServerConnectionDAL
{
private RedisServerConnectionDAL()
{
}
private static ShardedJedisSentinelPool pool;
private static ShardedJedis jedis;
private static ShardedJedisPipeline pipeline;
private static Set<String> redissentinels;
private static List<String> redismasters;
private static int redistimeout;
private static RedisServerConnectionDAL redisdal;
private static Map<String,String> redisconfmap;
public static int WAIT_IF_FAIL;
public static int RETRIES;
public synchronized static RedisServerConnectionDAL getInstance()
{
if(redisdal==null)
{
Properties redisprops = new Properties();
redisprops = ConfigReader.ReadConfig(Constant.REDIS_CONNECTION_CONFIG_FILE);
GenericObjectPoolConfig config = new GenericObjectPoolConfig();
redisconfmap = new HashMap(redisprops);
redisdal = new RedisServerConnectionDAL();
String redisNodesString = redisconfmap.get(Constant.REDIS_SENTINELS);
redissentinels = new HashSet<String>(Arrays.asList(redisNodesString.split(Constant.CONFIGURATION_FILE_MULTIVALUE_SEPERATOR)));
String redisMastersString = redisconfmap.get(Constant.REDIS_MASTERS);
redismasters = new ArrayList<String>();
redismasters.addAll(Arrays.asList(redisMastersString.split(Constant.CONFIGURATION_FILE_MULTIVALUE_SEPERATOR)));
redistimeout = Integer.parseInt(redisconfmap.get(Constant.REDIS_TIMEOUT));
WAIT_IF_FAIL = Integer.parseInt(redisconfmap.get(Constant.REDIS_WAIT_IF_FAIL));
RETRIES = Integer.parseInt(redisconfmap.get(Constant.REDIS_RETRIES));
pool = new ShardedJedisSentinelPool(redismasters, redissentinels, config, redistimeout);
jedis = pool.getResource();
pipeline = jedis.pipelined();
}
return redisdal;
}
public ShardedJedis getJedisResource()
{
jedis = pool.getResource();
return jedis;
}
public ShardedJedisPipeline getPipelineResource()
{
pipeline = jedis.pipelined();
return pipeline;
}
public ShardedJedisPipeline getPipeline()
{
return pipeline;
}
public ShardedJedis getJedis()
{
return jedis;
}
public static void resetRedisServerConnectionDal()
{
pipeline = null;
jedis = null;
redisdal = null;
}
}
所以，现在，无论我想与Redis互动，我都会做这样的事情
Jedis jedis = RedisServerConnectionDAL.getInstance.getJedis();
try
{
//code.....
}
catch(JedisConnectionException jce)
{
log.error(jce.getMessage());
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
jce.printStackTrace(pw);
log.error("Error:" + sw.toString());
if(retrycount < RedisServerConnectionDAL.RETRIES)
{
retrycount++;
log.error("Waiting for " + RedisServerConnectionDAL.WAIT_IF_FAIL + ", after which it will reconnect to Redis.");
try
{
Thread.sleep(RedisServerConnectionDAL.WAIT_IF_FAIL);
}
catch (InterruptedException e)
{
log.error(e.getMessage());
e.printStackTrace(pw);
log.error("Error:" + sw.toString());
log.error("Error while Sleeing!!!");
}
RedisServerConnectionDAL.resetRedisServerConnectionDal();
jedis = RedisServerConnectionDAL.getInstance();.getJedisResource();
pipeline = redisserverconnectiondal.getPipelineResource();
}
else
{
log.error("Redis retries exhausted");
log.error(jce.getMessage());
StringWriter sw1 = new StringWriter();
PrintWriter pw1 = new PrintWriter(sw1);
jce.printStackTrace(pw1);
log.error("Error:" + sw1.toString());
log.error("Error while executing pipeline in Redis!");
retrycount = 0;;
}
}
catch(Exception e)
{
log.error(e.getMessage());
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
e.printStackTrace(pw);
log.error("Error:" + sw.toString());
log.error("Error while executing pipeline in Redis!");
}
但我不断得到连接拒绝异常，连接关闭异常等异常。
有时我在行
的catch块中也会得到Null指针异常jedis = RedisServerConnectionDAL.getInstance();.getJedisResource();
异常的典型日志类似于
ERROR com.cleartrail.entityprofiling.rediscachecomponent.InMemoryDataAccessLayer - Error:redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketException: Connection reset
at redis.clients.jedis.Protocol.sendCommand(Protocol.java:94)
at redis.clients.jedis.Protocol.sendCommand(Protocol.java:74)
at redis.clients.jedis.Connection.sendCommand(Connection.java:78)
at redis.clients.jedis.BinaryClient.hexists(BinaryClient.java:257)
at redis.clients.jedis.Client.hexists(Client.java:174)
at redis.clients.jedis.Jedis.hexists(Jedis.java:705)
at redis.clients.jedis.ShardedJedis.hexists(ShardedJedis.java:213)
at com.cleartrail.entityprofiling.rediscachecomponent.InMemoryDataAccessLayer.checkForNewEntity(InMemoryDataAccessLayer.java:339)
at com.cleartrail.entityprofiling.rediscachecomponent.InMemoryDataAccessLayer.writeInMemoryData(InMemoryDataAccessLayer.java:215)
at com.cleartrail.entityprofiling.rediscachecomponent.InMemoryDataAccessLayer.run(InMemoryDataAccessLayer.java:715)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.net.SocketException: Connection reset
at java.net.SocketOutputStream.socketWrite(SocketOutputStream.java:113)
at java.net.SocketOutputStream.write(SocketOutputStream.java:153)
at redis.clients.util.RedisOutputStream.flushBuffer(RedisOutputStream.java:31)
at redis.clients.util.RedisOutputStream.writeIntCrLf(RedisOutputStream.java:186)
at redis.clients.jedis.Protocol.sendCommand(Protocol.java:81)
... 10 more
我知道我没有以正确的方式使用连接池。请建议正确的方法。另外，我使用jedis是多线程环境，其中两个线程将调用RedisServerConnectionDAL.getInstance（）。getJedisResource（）方法并与Redis交互。 Jedis线程安全吗？
答案 0 :(得分：0)
Jedis实例不是线程安全的，但您可以使用JedisPool获取每个线程的连接，并确保从池中获得有效连接。
lettuce client是线程安全的，可以为您管理自动重新连接。由于重新连接/连接重置，您不会在代码中看到任何异常。生菜也适用于Redis Sentinel。