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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mb644789379f291 2023-04-28 10:04:46 博主文章分类：db

文章标签 System List Test 文章分类 JavaScript 前端开发

redis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：
一、普通同步方式

最简单和基础的调用方式，

@Test  

public void test1Normal() {  

    Jedis jedis = new Jedis("localhost");  

    long start = System.currentTimeMillis();  

    for (int i = 0; i < 100000; i++) {  

        String result = jedis.set("n" + i, "n" + i);  

    }  

    long end = System.currentTimeMillis();  

    System.out.println("Simple SET: " + ((end - start)/1000.0) + " seconds");  

    jedis.disconnect();  

}

很简单吧，每次set之后都可以返回结果，标记是否成功。
二、事务方式(Transactions)

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：

@Test  

public void test2Trans() {  

    Jedis jedis = new Jedis("localhost");  

    long start = System.currentTimeMillis();  

    Transaction tx = jedis.multi();  

    for (int i = 0; i < 100000; i++) {  

        tx.set("t" + i, "t" + i);  

    }  

    List<Object> results = tx.exec();  

    long end = System.currentTimeMillis();  

    System.out.println("Transaction SET: " + ((end - start)/1000.0) + " seconds");  

    jedis.disconnect();  

}

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。
三、管道(Pipelining)

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：

@Test  

public void test3Pipelined() {  

    Jedis jedis = new Jedis("localhost");  

    Pipeline pipeline = jedis.pipelined();  

    long start = System.currentTimeMillis();  

    for (int i = 0; i < 100000; i++) {  

        pipeline.set("p" + i, "p" + i);  

    }  

    List<Object> results = pipeline.syncAndReturnAll();  

    long end = System.currentTimeMillis();  

    System.out.println("Pipelined SET: " + ((end - start)/1000.0) + " seconds");  

    jedis.disconnect();  

}

四、管道中调用事务

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：

@Test  

public void test4combPipelineTrans() {  

    jedis = new Jedis("localhost");  

    long start = System.currentTimeMillis();  

    Pipeline pipeline = jedis.pipelined();  

    pipeline.multi();  

    for (int i = 0; i < 100000; i++) {  

        pipeline.set("" + i, "" + i);  

    }  

    pipeline.exec();  

    List<Object> results = pipeline.syncAndReturnAll();  

    long end = System.currentTimeMillis();  

    System.out.println("Pipelined transaction: " + ((end - start)/1000.0) + " seconds");  

    jedis.disconnect();  

}

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。
五、分布式直连同步调用

@Test  

public void test5shardNormal() {  

    List<JedisShardInfo> shards = Arrays.asList(  

            new JedisShardInfo("localhost",6379),  

            new JedisShardInfo("localhost",6380));  


    ShardedJedis sharding = new ShardedJedis(shards);  


    long start = System.currentTimeMillis();  

    for (int i = 0; i < 100000; i++) {  

        String result = sharding.set("sn" + i, "n" + i);  

    }  

    long end = System.currentTimeMillis();  

    System.out.println("Simple@Sharing SET: " + ((end - start)/1000.0) + " seconds");  


    sharding.disconnect();  

}

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。
六、分布式直连异步调用

@Test  

public void test6shardpipelined() {  

    List<JedisShardInfo> shards = Arrays.asList(  

            new JedisShardInfo("localhost",6379),  

            new JedisShardInfo("localhost",6380));  


    ShardedJedis sharding = new ShardedJedis(shards);  


    ShardedJedisPipeline pipeline = sharding.pipelined();  

    long start = System.currentTimeMillis();  

    for (int i = 0; i < 100000; i++) {  

        pipeline.set("sp" + i, "p" + i);  

    }  

    List<Object> results = pipeline.syncAndReturnAll();  

    long end = System.currentTimeMillis();  

    System.out.println("Pipelined@Sharing SET: " + ((end - start)/1000.0) + " seconds");  


    sharding.disconnect();  

}

七、分布式连接池同步调用

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。

@Test  

public void test7shardSimplePool() {  

    List<JedisShardInfo> shards = Arrays.asList(  

            new JedisShardInfo("localhost",6379),  

            new JedisShardInfo("localhost",6380));  


    ShardedJedisPool pool = new ShardedJedisPool(new JedisPoolConfig(), shards);  


    ShardedJedis one = pool.getResource();  


    long start = System.currentTimeMillis();  

    for (int i = 0; i < 100000; i++) {  

        String result = one.set("spn" + i, "n" + i);  

    }  

    long end = System.currentTimeMillis();  

    pool.returnResource(one);  

    System.out.println("Simple@Pool SET: " + ((end - start)/1000.0) + " seconds");  


    pool.destroy();  

}

上面是同步方式，当然还有异步方式。
八、分布式连接池异步调用

@Test  

public void test8shardPipelinedPool() {  

    List<JedisShardInfo> shards = Arrays.asList(  

            new JedisShardInfo("localhost",6379),  

            new JedisShardInfo("localhost",6380));  


    ShardedJedisPool pool = new ShardedJedisPool(new JedisPoolConfig(), shards);  


    ShardedJedis one = pool.getResource();  


    ShardedJedisPipeline pipeline = one.pipelined();  


    long start = System.currentTimeMillis();  

    for (int i = 0; i < 100000; i++) {  

        pipeline.set("sppn" + i, "n" + i);  

    }  

    List<Object> results = pipeline.syncAndReturnAll();  

    long end = System.currentTimeMillis();  

    pool.returnResource(one);  

    System.out.println("Pipelined@Pool SET: " + ((end - start)/1000.0) + " seconds");  

    pool.destroy();  

}

九、需要注意的地方

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：

Transaction tx = jedis.multi();  

     for (int i = 0; i < 100000; i++) {  

         tx.set("t" + i, "t" + i);  

     }  

     System.out.println(tx.get("t1000").get());  //不允许  


     List<Object> results = tx.exec();  


     …  

     …  


     Pipeline pipeline = jedis.pipelined();  

     long start = System.currentTimeMillis();  

     for (int i = 0; i < 100000; i++) {  

         pipeline.set("p" + i, "p" + i);  

     }  

     System.out.println(pipeline.get("p1000").get()); //不允许  


     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。

十、测试

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。
十一、完整的测试代码

package com.example.nosqlclient;  


import java.util.Arrays;  

import java.util.List;  


import org.junit.AfterClass;  

import org.junit.BeforeClass;  

import org.junit.Test;  


import redis.clients.jedis.Jedis;  

import redis.clients.jedis.JedisPoolConfig;  

import redis.clients.jedis.JedisShardInfo;  

import redis.clients.jedis.Pipeline;  

import redis.clients.jedis.ShardedJedis;  

import redis.clients.jedis.ShardedJedisPipeline;  

import redis.clients.jedis.ShardedJedisPool;  

import redis.clients.jedis.Transaction;  


import org.junit.FixMethodOrder;  

import org.junit.runners.MethodSorters;  


@FixMethodOrder(MethodSorters.NAME_ASCENDING)  

public class TestJedis {  


    private static Jedis jedis;  

    private static ShardedJedis sharding;  

    private static ShardedJedisPool pool;  


    @BeforeClass  

    public static void setUpBeforeClass() throws Exception {  

        List<JedisShardInfo> shards = Arrays.asList(  

                new JedisShardInfo("localhost",6379),  

                new JedisShardInfo("localhost",6379)); //使用相同的ip:port,仅作测试  



        jedis = new Jedis("localhost");  

        sharding = new ShardedJedis(shards);  


        pool = new ShardedJedisPool(new JedisPoolConfig(), shards);  

    }  


    @AfterClass  

    public static void tearDownAfterClass() throws Exception {  

        jedis.disconnect();  

        sharding.disconnect();  

        pool.destroy();  

    }  


    @Test  

    public void test1Normal() {  

        long start = System.currentTimeMillis();  

        for (int i = 0; i < 100000; i++) {  

            String result = jedis.set("n" + i, "n" + i);  

        }  

        long end = System.currentTimeMillis();  

        System.out.println("Simple SET: " + ((end - start)/1000.0) + " seconds");  

    }  


    @Test  

    public void test2Trans() {  

        long start = System.currentTimeMillis();  

        Transaction tx = jedis.multi();  

        for (int i = 0; i < 100000; i++) {  

            tx.set("t" + i, "t" + i);  

        }  

        //System.out.println(tx.get("t1000").get());  


        List<Object> results = tx.exec();  

        long end = System.currentTimeMillis();  

        System.out.println("Transaction SET: " + ((end - start)/1000.0) + " seconds");  

    }  


    @Test  

    public void test3Pipelined() {  

        Pipeline pipeline = jedis.pipelined();  

        long start = System.currentTimeMillis();  

        for (int i = 0; i < 100000; i++) {  

            pipeline.set("p" + i, "p" + i);  

        }  

        //System.out.println(pipeline.get("p1000").get());  

        List<Object> results = pipeline.syncAndReturnAll();  

        long end = System.currentTimeMillis();  

        System.out.println("Pipelined SET: " + ((end - start)/1000.0) + " seconds");  

    }  


    @Test  

    public void test4combPipelineTrans() {  

        long start = System.currentTimeMillis();  

        Pipeline pipeline = jedis.pipelined();  

        pipeline.multi();  

        for (int i = 0; i < 100000; i++) {  

            pipeline.set("" + i, "" + i);  

        }  

        pipeline.exec();  

        List<Object> results = pipeline.syncAndReturnAll();  

        long end = System.currentTimeMillis();  

        System.out.println("Pipelined transaction: " + ((end - start)/1000.0) + " seconds");  

    }  


    @Test  

    public void test5shardNormal() {  

        long start = System.currentTimeMillis();  

        for (int i = 0; i < 100000; i++) {  

            String result = sharding.set("sn" + i, "n" + i);  

        }  

        long end = System.currentTimeMillis();  

        System.out.println("Simple@Sharing SET: " + ((end - start)/1000.0) + " seconds");  

    }  


    @Test  

    public void test6shardpipelined() {  

        ShardedJedisPipeline pipeline = sharding.pipelined();  

        long start = System.currentTimeMillis();  

        for (int i = 0; i < 100000; i++) {  

            pipeline.set("sp" + i, "p" + i);  

        }  

        List<Object> results = pipeline.syncAndReturnAll();  

        long end = System.currentTimeMillis();  

        System.out.println("Pipelined@Sharing SET: " + ((end - start)/1000.0) + " seconds");  

    }  


    @Test  

    public void test7shardSimplePool() {  

        ShardedJedis one = pool.getResource();  


        long start = System.currentTimeMillis();  

        for (int i = 0; i < 100000; i++) {  

            String result = one.set("spn" + i, "n" + i);  

        }  

        long end = System.currentTimeMillis();  

        pool.returnResource(one);  

        System.out.println("Simple@Pool SET: " + ((end - start)/1000.0) + " seconds");  

    }  


    @Test  

    public void test8shardPipelinedPool() {  

        ShardedJedis one = pool.getResource();  


        ShardedJedisPipeline pipeline = one.pipelined();  


        long start = System.currentTimeMillis();  

        for (int i = 0; i < 100000; i++) {  

            pipeline.set("sppn" + i, "n" + i);  

        }  

        List<Object> results = pipeline.syncAndReturnAll();  

        long end = System.currentTimeMillis();  

        pool.returnResource(one);  

        System.out.println("Pipelined@Pool SET: " + ((end - start)/1000.0) + " seconds");  

    }  

}