久久精品国产亚洲AV不卡,久久精品人妻中文系列,久久最新免费视频

本篇文章給大家?guī)淼膬?nèi)容是關(guān)于redis的事務(wù)操作的命令與執(zhí)行操作（代碼），有一定的參考價值，有需要的朋友可以參考一下，希望對你有所幫助。

序

本文主要研究一下redis的事務(wù)操作

命令

multi與exec

命令行

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實例

    @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"));     }

部分執(zhí)行

命令行

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實例

    @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與discard

命令行

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實例

    @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");         //需要有multi才可以執(zhí)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<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));     }

小結(jié)

reids提供multi exec/discard指令，類似open commit/rollback transaction，不過exec遇到類型操作等錯誤時不會滾，該成功執(zhí)行的命令還是成功執(zhí)行，該失敗的還是失敗
multi exec保證的是，只要exec命令有執(zhí)行成功，則事務(wù)中一系列的命令都能執(zhí)行，如果exec因為網(wǎng)絡(luò)等問題，server端沒有接收到，則事務(wù)中的一系列命令都不會被執(zhí)行
discard需要在有調(diào)用multi的前提下才能使用，該命令會清空事務(wù)隊列等待執(zhí)行的命令
redis提供watch指令，可以配合multi exec來使用，可以實現(xiàn)類似數(shù)據(jù)庫的樂觀鎖的機制，一旦watch的key被其他client有更新，則整個exec操作失敗