redis分布式算法原理:
本例中我们打开了两个redis服务，一个6379端口，一个6380端口，那么我们存储数据的时候是怎么分配的了，object1经过hsah到了他的位置上，存放到cacheA节点上，其它如object2，object3，object4也到了各自的位置，每个如cacheA的节点其实就是一个redis服务，顺时针分配object1分配到了cacheA上，但是这样有一个问题，那就是分配不均匀，所以就有了cacheA，cacheB，cacheC的虚拟节点（图中没有示例），每个虚拟节点的数据映射回自己的主节点，那么数据的分配最大程度上就分配均匀了
1.redis分布式连接池
public class RedisShardedPool { private static ShardedJedisPool pool;//Sharded Jedis连接池 private static Integer maxTotal = Integer.valueOf(PropertiesUtil.getProperty("redis.max.total","20")); //最大连接数 private static Integer maxIdle = Integer.valueOf(PropertiesUtil.getProperty("redis.max.idle","10"));//在jedispool中最大的idle状态（空闲的）的jedis实例的个数 private static Integer minIdle = Integer.valueOf(PropertiesUtil.getProperty("redis.min.idle","2"));//在jedispool中最小的idle状态（空闲的）的jedis实例的个数 private static Boolean testOnBorrow = Boolean.valueOf(PropertiesUtil.getProperty("redis.test.borrow","true"));//在borrow一个Jedis实例的时候，是否要进行验证操作，如果赋值true，那么得到的jedis实例肯定是可用的 private static Boolean testOnReturn = Boolean.valueOf(PropertiesUtil.getProperty("redis.test.return","true"));//在borrow一个Jedis实例的时候，是否要进行验证操作，如果赋值true，则放回jedispool的jedis实例肯定是可用的 private static String redis1Ip = PropertiesUtil.getProperty("redis1.ip"); private static Integer redis1Port = Integer.valueOf(PropertiesUtil.getProperty("redis1.port")); private static String redis2Ip = PropertiesUtil.getProperty("redis2.ip"); private static Integer redis2Port = Integer.valueOf(PropertiesUtil.getProperty("redis2.port")); private static void initPool(){ JedisPoolConfig config = new JedisPoolConfig(); config.setMaxTotal(maxTotal); config.setMaxIdle(maxIdle); config.setMinIdle(minIdle); config.setTestOnBorrow(testOnBorrow); config.setTestOnReturn(testOnReturn); config.setBlockWhenExhausted(true);//连接耗尽的时候是否阻塞，true：阻塞，false:抛出异常 //pool = new JedisPool(config,redisIp,redisPort,1000*2); JedisShardInfo info1 = new JedisShardInfo(redis1Ip,redis1Port,1000*2); //info1.setPassword("ddddd");//如果有密码的话 JedisShardInfo info2 = new JedisShardInfo(redis2Ip,redis2Port,1000*2); List<JedisShardInfo> jedisShardInfoList = new ArrayList<JedisShardInfo>(2); jedisShardInfoList.add(info1); jedisShardInfoList.add(info2); pool = new ShardedJedisPool(config,jedisShardInfoList, Hashing.MURMUR_HASH, Sharded.DEFAULT_KEY_TAG_PATTERN); } static { initPool(); } /* public static Jedis getJedis(){ return pool.getResource(); }*/ public static ShardedJedis getJedis(){ return pool.getResource(); } public static void returnBrokenResource(ShardedJedis jedis){ pool.returnBrokenResource(jedis); } public static void returnResource(ShardedJedis jedis){ pool.returnResource(jedis); } public static void main (String[] args){ ShardedJedis jedis = pool.getResource(); for (int i=0;i<10;i++){ jedis.set("key"+i,"value"+i); } //jedis.set("geelykey","geelyvalue"); returnResource(jedis); // pool.destroy();//临时调用 System.out.println("program is end"); } }
2.写一个工具类封装redis分布式操作方法
public class RedisShardedPoolUtil { /*设置key的有效期，单位是秒*/ public static Long expire(String key,int exTime){ ShardedJedis jedis = null; Long result = null; try { jedis = RedisShardedPool.getJedis(); result = jedis.expire(key,exTime); } catch (Exception e) { log.error("expire key:{} exTime:{} error",key,exTime,e); RedisShardedPool.returnBrokenResource(jedis); return result; } RedisShardedPool.returnResource(jedis); return result; } //exTime的单位是秒 public static String setEx(String key,String value,int exTime){ ShardedJedis jedis = null; String result = null; try { jedis = RedisShardedPool.getJedis(); result = jedis.setex(key,exTime,value); } catch (Exception e) { log.error("setex key:{} exTime:{} value:{} error",key,exTime,value,e); RedisShardedPool.returnBrokenResource(jedis); return result; } RedisShardedPool.returnResource(jedis); return result; } public static String set(String key,String value){ ShardedJedis jedis = null; String result = null; try { jedis = RedisShardedPool.getJedis(); result = jedis.set(key, value); } catch (Exception e) { log.error("set key:{} value:{} error",key,value,e); RedisShardedPool.returnBrokenResource(jedis); return result; } RedisShardedPool.returnResource(jedis); return result; } public static String getSet(String key,String value){ ShardedJedis jedis = null; String result = null; try { jedis = RedisShardedPool.getJedis(); result = jedis.getSet(key, value); } catch (Exception e) { log.error("getSet key:{} value:{} error",key,value,e); RedisShardedPool.returnBrokenResource(jedis); return result; } RedisShardedPool.returnResource(jedis); return result; } public static Long setnx(String key,String value){ ShardedJedis jedis = null; Long result = null; try { jedis = RedisShardedPool.getJedis(); result = jedis.setnx(key, value); } catch (Exception e) { log.error("set key:{} value:{} error",key,value,e); RedisShardedPool.returnBrokenResource(jedis); return result; } RedisShardedPool.returnResource(jedis); return result; } public static String get(String key){ ShardedJedis jedis = null; String result = null; try { jedis = RedisShardedPool.getJedis(); result = jedis.get(key); } catch (Exception e) { log.error("get key:{} error",key,e); RedisShardedPool.returnBrokenResource(jedis); return result; } RedisShardedPool.returnResource(jedis); return result; } public static Long del(String key){ ShardedJedis jedis = null; Long result = null; try { jedis = RedisShardedPool.getJedis(); result = jedis.del(key); } catch (Exception e) { log.error("del key:{} error",key,e); RedisShardedPool.returnBrokenResource(jedis); return result; } RedisShardedPool.returnResource(jedis); return result; } public static void main (String[] args){ Jedis jedis = RedisPool.getJedis(); RedisPoolUtil.set("keyTest","value"); String value = RedisPoolUtil.get("keyTest"); RedisPoolUtil.setEx("kevex","valueex",60*10); RedisPoolUtil.expire("keyTest",60*20); RedisPoolUtil.del("keyTest"); System.out.println("end"); } }