Spring RedisTemplate 批量獲取值的2種方式
阿新 • • 發佈:2019-01-30
1、利用mGet
還有一點,就是查詢返回的結果,和鍵的順序是一一對應的,如果沒查到,會返回null值。
List<String> keys = new ArrayList<>();
//初始keys
List<YourObject> list = this.redisTemplate.opsForValue().multiGet(keys);
2、利用PipeLine其實2者底層都是用到execute方法,multiGet在使用連線是沒用到pipeline,一條命令直接傳給Redis,Redis返回結果。而executePipelined實際上一條或多條命令,但是共用一個連線。List<YourObject> list = this.redisTemplate.executePipelined(new RedisCallback<YourObject>() { @Override public YourObject doInRedis(RedisConnection connection) throws DataAccessException { StringRedisConnection conn = (StringRedisConnection)connection; for (String key : keys) { conn.get(key); } return null; } });
/** * Executes the given action object within a connection that can be exposed or not. Additionally, the connection can * be pipelined. Note the results of the pipeline are discarded (making it suitable for write-only scenarios). * * @param <T> return type * @param action callback object to execute * @param exposeConnection whether to enforce exposure of the native Redis Connection to callback code * @param pipeline whether to pipeline or not the connection for the execution * @return object returned by the action */ 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 = getConnectionFactory(); RedisConnection conn = null; try { if (enableTransactionSupport) { // only bind resources in case of potential transaction synchronization conn = RedisConnectionUtils.bindConnection(factory, enableTransactionSupport); } else { conn = RedisConnectionUtils.getConnection(factory); } boolean existingConnection = TransactionSynchronizationManager.hasResource(factory); RedisConnection connToUse = preProcessConnection(conn, existingConnection); boolean pipelineStatus = connToUse.isPipelined(); if (pipeline && !pipelineStatus) { //開啟管道 connToUse.openPipeline(); } RedisConnection connToExpose = (exposeConnection ? connToUse : createRedisConnectionProxy(connToUse)); T result = action.doInRedis(connToExpose); if (pipeline && !pipelineStatus) {// 關閉管道 connToUse.closePipeline(); } // TODO: any other connection processing? return postProcessResult(result, connToUse, existingConnection); } finally { if (!enableTransactionSupport) { RedisConnectionUtils.releaseConnection(conn, factory); } } }
還有一點,就是查詢返回的結果,和鍵的順序是一一對應的,如果沒查到,會返回null值。