JedisPool
获取Jedis实例需要从JedisPool中获取
用完Jedis实例需要返还给JedisPool
如果Jedis在使用过程中出错,则也需要还给JedisPool
案例
import redis.clients.jedis.Jedis; import redis.clients.jedis.JedisPool; import redis.clients.jedis.JedisPoolConfig; public class JedisPoolUtil { private static volatile JedisPool jedisPool = null;//被volatile修饰的变量不会被本地线程缓存,对该变量的读写都是直接操作共享内存。 private JedisPoolUtil() {} public static JedisPool getJedisPoolInstance() { if(null == jedisPool) { synchronized (JedisPoolUtil.class) { if(null == jedisPool) { JedisPoolConfig poolConfig = new JedisPoolConfig(); poolConfig.setMaxActive(1000); poolConfig.setMaxIdle(32); poolConfig.setMaxWait(100*1000); poolConfig.setTestOnBorrow(true); jedisPool = new JedisPool(poolConfig,"127.0.0.1"); } } } return jedisPool; } public static void release(JedisPool jedisPool,Jedis jedis) { if(null != jedis) { jedisPool.returnResourceObject(jedis); } } }
import redis.clients.jedis.Jedis; import redis.clients.jedis.JedisPool; public class Test01 { public static void main(String[] args) { JedisPool jedisPool = JedisPoolUtil.getJedisPoolInstance(); Jedis jedis = null; try { jedis = jedisPool.getResource(); jedis.set("k18","v183"); } catch (Exception e) { e.printStackTrace(); }finally{ JedisPoolUtil.release(jedisPool, jedis); } } }
配置总结all
JedisPool的配置参数大部分是由JedisPoolConfig的对应项来赋值的。 maxActive:控制一个pool可分配多少个jedis实例,通过pool.getResource()来获取;如果赋值为-1,则表示不限制;如果pool已经分配了maxActive个jedis实例,则此时pool的状态为exhausted。 maxIdle:控制一个pool最多有多少个状态为idle(空闲)的jedis实例; whenExhaustedAction:表示当pool中的jedis实例都被allocated完时,pool要采取的操作;默认有三种。 WHEN_EXHAUSTED_FAIL --> 表示无jedis实例时,直接抛出NoSuchElementException; WHEN_EXHAUSTED_BLOCK --> 则表示阻塞住,或者达到maxWait时抛出JedisConnectionException; WHEN_EXHAUSTED_GROW --> 则表示新建一个jedis实例,也就说设置的maxActive无用; maxWait:表示当borrow一个jedis实例时,最大的等待时间,如果超过等待时间,则直接抛JedisConnectionException; testOnBorrow:获得一个jedis实例的时候是否检查连接可用性(ping());如果为true,则得到的jedis实例均是可用的; testOnReturn:return 一个jedis实例给pool时,是否检查连接可用性(ping()); testWhileIdle:如果为true,表示有一个idle object evitor线程对idle object进行扫描,如果validate失败,此object会被从pool中drop掉;这一项只有在timeBetweenEvictionRunsMillis大于0时才有意义; timeBetweenEvictionRunsMillis:表示idle object evitor两次扫描之间要sleep的毫秒数; numTestsPerEvictionRun:表示idle object evitor每次扫描的最多的对象数; minEvictableIdleTimeMillis:表示一个对象至少停留在idle状态的最短时间,然后才能被idle object evitor扫描并驱逐;这一项只有在timeBetweenEvictionRunsMillis大于0时才有意义; softMinEvictableIdleTimeMillis:在minEvictableIdleTimeMillis基础上,加入了至少minIdle个对象已经在pool里面了。如果为-1,evicted不会根据idle time驱逐任何对象。如果minEvictableIdleTimeMillis>0,则此项设置无意义,且只有在timeBetweenEvictionRunsMillis大于0时才有意义; lifo:borrowObject返回对象时,是采用DEFAULT_LIFO(last in first out,即类似cache的最频繁使用队列),如果为False,则表示FIFO队列; ================================================================================================================== 其中JedisPoolConfig对一些参数的默认设置如下: testWhileIdle=true minEvictableIdleTimeMills=60000 timeBetweenEvictionRunsMillis=30000 numTestsPerEvictionRun=-1