Redis的事件操纵的敕令与实行操纵(代码)【MySQL教程】,redis
序
本文重要研究一下redis的事件操纵
敕令
multi与exec
敕令行
127.0.0.1:6379> multi OK 127.0.0.1:6379> incr total QUEUED 127.0.0.1:6379> incr len QUEUED 127.0.0.1:6379> exec 1) (integer) 2 2) (integer) 2 127.0.0.1:6379> get total "2" 127.0.0.1:6379> get len "2"
lettuce实例
@Test public void testMultiExec(){ RedisClient client = RedisClient.create("redis://192.168.99.100:6379/0"); StatefulRedisConnection<String, String> connection = client.connect(); RedisCommands<String, String> syncCommands = connection.sync(); syncCommands.set("hello","1"); syncCommands.set("world","2"); syncCommands.multi(); syncCommands.incr("hello"); syncCommands.incr("world"); //DefaultTransactionResult[wasRolledBack=false,result=[1, 2, 1, 3, 1]] TransactionResult transactionResult = syncCommands.exec(); System.out.println(transactionResult); System.out.println(syncCommands.get("hello")); System.out.println(syncCommands.get("world")); }
部份实行
敕令行
127.0.0.1:6379> multi OK 127.0.0.1:6379> set a hello QUEUED 127.0.0.1:6379> set b world QUEUED 127.0.0.1:6379> incr a QUEUED 127.0.0.1:6379> set c part QUEUED 127.0.0.1:6379> exec 1) OK 2) OK 3) (error) ERR value is not an integer or out of range 4) OK 127.0.0.1:6379> get a "hello" 127.0.0.1:6379> get b "world" 127.0.0.1:6379> get c "part"
lettuce实例
@Test public void testMultiExecError(){ RedisClient client = RedisClient.create("redis://192.168.99.100:6379/0"); StatefulRedisConnection<String, String> connection = client.connect(); RedisCommands<String, String> syncCommands = connection.sync(); syncCommands.multi(); syncCommands.set("a","hello"); syncCommands.set("b","world"); syncCommands.incr("a"); syncCommands.set("c","part"); //DefaultTransactionResult[wasRolledBack=false,result=[OK, OK, io.lettuce.core.RedisCommandExecutionException: ERR value is not an integer or out of range, OK, 1]] TransactionResult transactionResult = syncCommands.exec(); System.out.println(transactionResult); System.out.println(syncCommands.get("a")); System.out.println(syncCommands.get("b")); System.out.println(syncCommands.get("c")); }
multi与discard
敕令行
127.0.0.1:6379> set sum 1 OK 127.0.0.1:6379> multi OK 127.0.0.1:6379> incr sum QUEUED 127.0.0.1:6379> discard OK 127.0.0.1:6379> get sum "1"
lettuce实例
@Test public void testMultiDiscard(){ RedisClient client = RedisClient.create("redis://192.168.99.100:6379/0"); StatefulRedisConnection<String, String> connection = client.connect(); RedisCommands<String, String> syncCommands = connection.sync(); syncCommands.incr("key1"); syncCommands.multi(); syncCommands.incr("key1"); //须要有multi才够实行discard,胜利返回OK String result = syncCommands.discard(); System.out.println(result); System.out.println(syncCommands.get("key1")); }
check and set
@Test public void testWatch(){ RedisClient client = RedisClient.create("redis://192.168.99.100:6379/0"); StatefulRedisConnection<String, String> connection = client.connect(); RedisCommands<String, String> syncCommands = connection.sync(); String key = "key"; syncCommands.watch(key); //another connection StatefulRedisConnection<String, String> conn2 = client.connect(); RedisCommands<String, String> syncCommands2 = conn2.sync(); syncCommands2.set(key, "a"); syncCommands.multi(); syncCommands.append(key, "b"); //DefaultTransactionResult [wasRolledBack=true, responses=0] TransactionResult transactionResult = syncCommands.exec(); System.out.println(transactionResult); System.out.println(syncCommands.get(key)); }
小结
reids供应multi exec/discard指令,相似open commit/rollback transaction,不过exec碰到范例操纵等错误时不会滚,该胜利实行的敕令照样胜利实行,该失利的照样失利
multi exec保证的是,只需exec敕令有实行胜利,则事件中一系列的敕令都能实行,假如exec由于收集等题目,server端没有接收到,则事件中的一系列敕令都不会被实行
discard须要在有挪用multi的前提下才运用,该敕令会清空事件行列守候实行的敕令
redis供应watch指令,能够合营multi exec来运用,能够完成相似数据库的乐观锁的机制,一旦watch的key被其他client有更新,则全部exec操纵失利
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