Redis中事务操作的命令有哪些

小编给大家分享一下Redis中事务操作的命令有哪些，希望大家阅读完这篇文章之后都有所收获，下面让我们一起去探讨吧！

命令

multi与exec

• 命令行

127.0.0.1:6379> multiOK127.0.0.1:6379> incr totalQUEUED127.0.0.1:6379> incr lenQUEUED127.0.0.1:6379> exec1) (integer) 22) (integer) 2127.0.0.1:6379> 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 connection = client.connect();        RedisCommands 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"));    }

部分执行

• 命令行

127.0.0.1:6379> multiOK127.0.0.1:6379> set a helloQUEUED127.0.0.1:6379> set b worldQUEUED127.0.0.1:6379> incr aQUEUED127.0.0.1:6379> set c partQUEUED127.0.0.1:6379> exec1) OK2) OK3) (error) ERR value is not an integer or out of range4) OK127.0.0.1:6379> 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 connection = client.connect();        RedisCommands 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

• 命令行

127.0.0.1:6379> set sum 1OK127.0.0.1:6379> multiOK127.0.0.1:6379> incr sumQUEUED127.0.0.1:6379> discardOK127.0.0.1:6379> get sum"1"

• lettuce实例

    @Test    public void testMultiDiscard(){        RedisClient client = RedisClient.create("redis://192.168.99.100:6379/0");        StatefulRedisConnection connection = client.connect();        RedisCommands syncCommands = connection.sync();        syncCommands.incr("key1");        syncCommands.multi();        syncCommands.incr("key1");        //需要有multi才可以执行discard，成功返回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 connection = client.connect();        RedisCommands syncCommands = connection.sync();        String key = "key";        syncCommands.watch(key);        //another connection        StatefulRedisConnection conn2 = client.connect();        RedisCommands 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));    }

• reids提供multi exec/discard指令，类似open commit/rollback transaction，不过exec遇到类型操作等错误时不会滚，该成功执行的命令还是成功执行，该失败的还是失败

• multi exec保证的是，只要exec命令有执行成功，则事务中一系列的命令都能执行，如果exec因为网络等问题，server端没有接收到，则事务中的一系列命令都不会被执行

• discard需要在有调用multi的前提下才能使用，该命令会清空事务队列等待执行的命令

• redis提供watch指令，可以配合multi exec来使用，可以实现类似数据库的乐观锁的机制，一旦watch的key被其他client有更新，则整个exec操作失败

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