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jedis是一个著名的key-value存储系统，而作为其官方推荐的java版客户端jedis也非常强大和稳定，支持事务、管道及有jedis自身实现的分布式。
在这里对jedis关于事务、管道和分布式的调用方式做一个简单的介绍和对比：
最简单和基础的调用方式：
1 @Test 2 public void test1Normal() { 3 Jedis jedis = new Jedis("localhost"); 4 long start = System.currentTimeMillis(); 5 for (int i = 0; i < 100000; i++) { 6 String result = jedis.set("n" + i, "n" + i); 7 } 8 long end = System.currentTimeMillis(); 9 System.out.println("Simple SET: " + ((end - start)/1000.0) + " seconds"); 10 jedis.disconnect(); 11 }
很简单吧，每次set之后都可以返回结果，标记是否成功。
redis的事务很简单，他主要目的是保障，一个client发起的事务中的命令可以连续的执行，而中间不会插入其他client的命令。
看下面例子：
1 @Test 2 public void test2Trans() { 3 Jedis jedis = new Jedis("localhost"); 4 long start = System.currentTimeMillis(); 5 Transaction tx = jedis.multi(); 6 for (int i = 0; i < 100000; i++) { 7 tx.set("t" + i, "t" + i); 8 } 9 List<Object> results = tx.exec(); 10 long end = System.currentTimeMillis(); 11 System.out.println("Transaction SET: " + ((end - start)/1000.0) + " seconds"); 12 jedis.disconnect(); 13 }
我们调用jedis.watch(…)方法来监控key，如果调用后key值发生变化，则整个事务会执行失败。另外，事务中某个操作失败，并不会回滚其他操作。这一点需要注意。还有，我们可以使用discard()方法来取消事务。
有时，我们需要采用异步方式，一次发送多个指令，不同步等待其返回结果。这样可以取得非常好的执行效率。这就是管道，调用方法如下：
1 @Test 2 public void test3Pipelined() { 3 Jedis jedis = new Jedis("localhost"); 4 Pipeline pipeline = jedis.pipelined(); 5 long start = System.currentTimeMillis(); 6 for (int i = 0; i < 100000; i++) { 7 pipeline.set("p" + i, "p" + i); 8 } 9 List<Object> results = pipeline.syncAndReturnAll(); 10 long end = System.currentTimeMillis(); 11 System.out.println("Pipelined SET: " + ((end - start)/1000.0) + " seconds"); 12 jedis.disconnect(); 13 }
就Jedis提供的方法而言，是可以做到在管道中使用事务，其代码如下：
1 @Test 2 public void test4combPipelineTrans() { 3 jedis = new Jedis("localhost"); 4 long start = System.currentTimeMillis(); 5 Pipeline pipeline = jedis.pipelined(); 6 pipeline.multi(); 7 for (int i = 0; i < 100000; i++) { 8 pipeline.set("" + i, "" + i); 9 } 10 pipeline.exec(); 11 List<Object> results = pipeline.syncAndReturnAll(); 12 long end = System.currentTimeMillis(); 13 System.out.println("Pipelined transaction: " + ((end - start)/1000.0) + " seconds"); 14 jedis.disconnect(); 15 }
但是经测试（见本文后续部分），发现其效率和单独使用事务差不多，甚至还略微差点。
1 Test 2 public void test5shardNormal() { 3 List<JedisShardInfo> shards = Arrays.asList( 4 new JedisShardInfo("localhost",6379), 5 new JedisShardInfo("localhost",6380)); 6 7 ShardedJedis sharding = new ShardedJedis(shards); 8 9 long start = System.currentTimeMillis(); 10 for (int i = 0; i < 100000; i++) { 11 String result = sharding.set("sn" + i, "n" + i); 12 } 13 long end = System.currentTimeMillis(); 14 System.out.println("Simple@Sharing SET: " + ((end - start)/1000.0) + " seconds"); 15 16 sharding.disconnect(); 17 }
这个是分布式直接连接，并且是同步调用，每步执行都返回执行结果。类似地，还有异步管道调用。
1 @Test 2 public void test6shardpipelined() { 3 List<JedisShardInfo> shards = Arrays.asList( 4 new JedisShardInfo("localhost",6379), 5 new JedisShardInfo("localhost",6380)); 6 7 ShardedJedis sharding = new ShardedJedis(shards); 8 9 ShardedJedisPipeline pipeline = sharding.pipelined(); 10 long start = System.currentTimeMillis(); 11 for (int i = 0; i < 100000; i++) { 12 pipeline.set("sp" + i, "p" + i); 13 } 14 List<Object> results = pipeline.syncAndReturnAll(); 15 long end = System.currentTimeMillis(); 16 System.out.println("Pipelined@Sharing SET: " + ((end - start)/1000.0) + " seconds"); 17 18 sharding.disconnect(); 19 }
如果，你的分布式调用代码是运行在线程中，那么上面两个直连调用方式就不合适了，因为直连方式是非线程安全的，这个时候，你就必须选择连接池调用。
1 @Test 2 public void test7shardSimplePool() { 3 List<JedisShardInfo> shards = Arrays.asList( 4 new JedisShardInfo("localhost",6379), 5 new JedisShardInfo("localhost",6380)); 6 7 ShardedJedisPool pool = new ShardedJedisPool(new JedisPoolConfig(), shards); 8 9 ShardedJedis one = pool.getResource(); 10 11 long start = System.currentTimeMillis(); 12 for (int i = 0; i < 100000; i++) { 13 String result = one.set("spn" + i, "n" + i); 14 } 15 long end = System.currentTimeMillis(); 16 pool.returnResource(one); 17 System.out.println("Simple@Pool SET: " + ((end - start)/1000.0) + " seconds"); 18 19 pool.destroy(); 20 }
上面是同步方式，当然还有异步方式。
1 @Test 2 public void test8shardPipelinedPool() { 3 List<JedisShardInfo> shards = Arrays.asList( 4 new JedisShardInfo("localhost",6379), 5 new JedisShardInfo("localhost",6380)); 6 7 ShardedJedisPool pool = new ShardedJedisPool(new JedisPoolConfig(), shards); 8 9 ShardedJedis one = pool.getResource(); 10 11 ShardedJedisPipeline pipeline = one.pipelined(); 12 13 long start = System.currentTimeMillis(); 14 for (int i = 0; i < 100000; i++) { 15 pipeline.set("sppn" + i, "n" + i); 16 } 17 List<Object> results = pipeline.syncAndReturnAll(); 18 long end = System.currentTimeMillis(); 19 pool.returnResource(one); 20 System.out.println("Pipelined@Pool SET: " + ((end - start)/1000.0) + " seconds"); 21 pool.destroy(); 22 }
事务和管道都是异步模式。在事务和管道中不能同步查询结果。比如下面两个调用，都是不允许的：
1 Transaction tx = jedis.multi(); 2 for (int i = 0; i < 100000; i++) { 3 tx.set("t" + i, "t" + i); 4 } 5 System.out.println(tx.get("t1000").get()); //不允许 6 7 List<Object> results = tx.exec(); 8 9 … 10 … 11 12 Pipeline pipeline = jedis.pipelined(); 13 long start = System.currentTimeMillis(); 14 for (int i = 0; i < 100000; i++) { 15 pipeline.set("p" + i, "p" + i); 16 } 17 System.out.println(pipeline.get("p1000").get()); //不允许 18 19 List<Object> results = pipeline.syncAndReturnAll();
事务和管道都是异步的，个人感觉，在管道中再进行事务调用，没有必要，不如直接进行事务模式。
分布式中，连接池的性能比直连的性能略好(见后续测试部分)。
分布式调用中不支持事务。
因为事务是在服务器端实现，而在分布式中，每批次的调用对象都可能访问不同的机器，所以，没法进行事务。
运行上面的代码，进行测试，其结果如下：
Simple SET: 5.227 seconds Transaction SET: 0.5 seconds Pipelined SET: 0.353 seconds Pipelined transaction: 0.509 seconds Simple@Sharing SET: 5.289 seconds Pipelined@Sharing SET: 0.348 seconds Simple@Pool SET: 5.039 seconds Pipelined@Pool SET: 0.401 seconds
另外，经测试分布式中用到的机器越多，调用会越慢。上面是2片，下面是5片：
Simple@Sharing SET: 5.494 seconds Pipelined@Sharing SET: 0.51 seconds Simple@Pool SET: 5.223 seconds Pipelined@Pool SET: 0.518 seconds
下面是10片：
Simple@Sharing SET: 5.9 seconds Pipelined@Sharing SET: 0.794 seconds Simple@Pool SET: 5.624 seconds Pipelined@Pool SET: 0.762 seconds
下面是100片：
Simple@Sharing SET: 14.055 seconds Pipelined@Sharing SET: 8.185 seconds Simple@Pool SET: 13.29 seconds Pipelined@Pool SET: 7.767 seconds
分布式中，连接池方式调用不但线程安全外，根据上面的测试数据，也可以看出连接池比直连的效率更好。
1 package com.example.nosqlclient; 2 3 import java.util.Arrays; 4 import java.util.List; 5 6 import org.junit.AfterClass; 7 import org.junit.BeforeClass; 8 import org.junit.Test; 9 10 import redis.clients.jedis.Jedis; 11 import redis.clients.jedis.JedisPoolConfig; 12 import redis.clients.jedis.JedisShardInfo; 13 import redis.clients.jedis.Pipeline; 14 import redis.clients.jedis.ShardedJedis; 15 import redis.clients.jedis.ShardedJedisPipeline; 16 import redis.clients.jedis.ShardedJedisPool; 17 import redis.clients.jedis.Transaction; 18 19 import org.junit.FixMethodOrder; 20 import org.junit.runners.MethodSorters; 21 22 @FixMethodOrder(MethodSorters.NAME_ASCENDING) 23 public class TestJedis { 24 25 private static Jedis jedis; 26 private static ShardedJedis sharding; 27 private static ShardedJedisPool pool; 28 29 @BeforeClass 30 public static void setUpBeforeClass() throws Exception { 31 List<JedisShardInfo> shards = Arrays.asList( 32 new JedisShardInfo("localhost",6379), 33 new JedisShardInfo("localhost",6379)); //使用相同的ip:port,仅作测试 34 35 36 jedis = new Jedis("localhost"); 37 sharding = new ShardedJedis(shards); 38 39 pool = new ShardedJedisPool(new JedisPoolConfig(), shards); 40 } 41 42 @AfterClass 43 public static void tearDownAfterClass() throws Exception { 44 jedis.disconnect(); 45 sharding.disconnect(); 46 pool.destroy(); 47 } 48 49 @Test 50 public void test1Normal() { 51 long start = System.currentTimeMillis(); 52 for (int i = 0; i < 100000; i++) { 53 String result = jedis.set("n" + i, "n" + i); 54 } 55 long end = System.currentTimeMillis(); 56 System.out.println("Simple SET: " + ((end - start)/1000.0) + " seconds"); 57 } 58 59 @Test 60 public void test2Trans() { 61 long start = System.currentTimeMillis(); 62 Transaction tx = jedis.multi(); 63 for (int i = 0; i < 100000; i++) { 64 tx.set("t" + i, "t" + i); 65 } 66 //System.out.println(tx.get("t1000").get()); 67 68 List<Object> results = tx.exec(); 69 long end = System.currentTimeMillis(); 70 System.out.println("Transaction SET: " + ((end - start)/1000.0) + " seconds"); 71 } 72 73 @Test 74 public void test3Pipelined() { 75 Pipeline pipeline = jedis.pipelined(); 76 long start = System.currentTimeMillis(); 77 for (int i = 0; i < 100000; i++) { 78 pipeline.set("p" + i, "p" + i); 79 } 80 //System.out.println(pipeline.get("p1000").get()); 81 List<Object> results = pipeline.syncAndReturnAll(); 82 long end = System.currentTimeMillis(); 83 System.out.println("Pipelined SET: " + ((end - start)/1000.0) + " seconds"); 84 } 85 86 @Test 87 public void test4combPipelineTrans() { 88 long start = System.currentTimeMillis(); 89 Pipeline pipeline = jedis.pipelined(); 90 pipeline.multi(); 91 for (int i = 0; i < 100000; i++) { 92 pipeline.set("" + i, "" + i); 93 } 94 pipeline.exec(); 95 List<Object> results = pipeline.syncAndReturnAll(); 96 long end = System.currentTimeMillis(); 97 System.out.println("Pipelined transaction: " + ((end - start)/1000.0) + " seconds"); 98 } 99 100 @Test 101 public void test5shardNormal() { 102 long start = System.currentTimeMillis(); 103 for (int i = 0; i < 100000; i++) { 104 String result = sharding.set("sn" + i, "n" + i); 105 } 106 long end = System.currentTimeMillis(); 107 System.out.println("Simple@Sharing SET: " + ((end - start)/1000.0) + " seconds"); 108 } 109 110 @Test 111 public void test6shardpipelined() { 112 ShardedJedisPipeline pipeline = sharding.pipelined(); 113 long start = System.currentTimeMillis(); 114 for (int i = 0; i < 100000; i++) { 115 pipeline.set("sp" + i, "p" + i); 116 } 117 List<Object> results = pipeline.syncAndReturnAll(); 118 long end = System.currentTimeMillis(); 119 System.out.println("Pipelined@Sharing SET: " + ((end - start)/1000.0) + " seconds"); 120 } 121 122 @Test 123 public void test7shardSimplePool() { 124 ShardedJedis one = pool.getResource(); 125 126 long start = System.currentTimeMillis(); 127 for (int i = 0; i < 100000; i++) { 128 String result = one.set("spn" + i, "n" + i); 129 } 130 long end = System.currentTimeMillis(); 131 pool.returnResource(one); 132 System.out.println("Simple@Pool SET: " + ((end - start)/1000.0) + " seconds"); 133 } 134 135 @Test 136 public void test8shardPipelinedPool() { 137 ShardedJedis one = pool.getResource(); 138 139 ShardedJedisPipeline pipeline = one.pipelined(); 140 141 long start = System.currentTimeMillis(); 142 for (int i = 0; i < 100000; i++) { 143 pipeline.set("sppn" + i, "n" + i); 144 } 145 List<Object> results = pipeline.syncAndReturnAll(); 146 long end = System.currentTimeMillis(); 147 pool.returnResource(one); 148 System.out.println("Pipelined@Pool SET: " + ((end - start)/1000.0) + " seconds"); 149 } 150 }
Redis的Java客户端Jedis的八种调用方式(事务、管道、分布式)介绍
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原文地址：http://www.cnblogs.com/link1988/p/5503692.html
