记Jedis客户端并发问题

拼搏现实的明天。 2022-05-16 09:14 260阅读 0赞

先来看问题，在对分布式锁进行压测时抛出异常：

java.lang.ClassCastException: java.lang.Long cannot be cast to [B
        at redis.clients.jedis.Connection.getStatusCodeReply(Connection.java:239)
        at redis.clients.jedis.Jedis.set(Jedis.java:139)
        at com.quancheng.shared.distribute.concurrent.JedisLock.acquire(JedisLock.java:55)
        at com.quancheng.shared.distribute.concurrent.JedisLock.tryLock(JedisLock.java:93)
        at com.quancheng.shared.distribute.impl.JedisLockTest$LockTask.run(JedisLockTest.java:76)

网上搜一下，都是说是Jedis并发问题，看看github主页issue：  
[https://github.com/xetorthio/jedis/issues?utf8=%E2%9C%93&q=java.lang.Long+cannot+be+cast+to+%5BB][https_github.com_xetorthio_jedis_issues_utf8_E2_9C_93_q_java.lang.Long_cannot_be_cast_to_5BB]  
![这里写图片描述][70]  
仔细看下来都是说多线程并发导致的问题，jedis官网指南：

/// Jedis implements Closeable. Hence, the jedis instance will be auto-closed after the last statement.
    try (Jedis jedis = pool.getResource()) {
      /// ... do stuff here ... for example
      jedis.set("foo", "bar");
      String foobar = jedis.get("foo");
      jedis.zadd("sose", 0, "car"); jedis.zadd("sose", 0, "bike"); 
      Set<String> sose = jedis.zrange("sose", 0, -1);
    }
    /// ... when closing your application:
    pool.close();

或者使用try-finally方式：

Jedis jedis = null;
    try {
      jedis = pool.getResource();
      /// ... do stuff here ... for example
      jedis.set("foo", "bar");
      String foobar = jedis.get("foo");
      jedis.zadd("sose", 0, "car"); jedis.zadd("sose", 0, "bike"); 
      Set<String> sose = jedis.zrange("sose", 0, -1);
    } finally {
      // You have to close jedis object. If you don't close then // it doesn't release back to pool and you can't get a new // resource from pool. if (jedis != null) { jedis.close(); } } /// ... when closing your application: pool.close();

说的很明白，必须得释放jedis object；每个线程使用一个jedis object；  
再结合这位网友分享的经验：[https://yq.aliyun.com/articles/236384?spm=a2c4e.11153940.blogcont236383.20.d17a1c96Lm3AHM\#cc8][https_yq.aliyun.com_articles_236384_spm_a2c4e.11153940.blogcont236383.20.d17a1c96Lm3AHM_cc8]  
直接看【八、java.lang.ClassCastException: java.lang.Long cannot be cast to java.util.List】  
这样看来，是我们自己本身的代码出了问题，并不是大牛的问题^\_^

[https_github.com_xetorthio_jedis_issues_utf8_E2_9C_93_q_java.lang.Long_cannot_be_cast_to_5BB]: https://github.com/xetorthio/jedis/issues?utf8=%E2%9C%93&q=java.lang.Long+cannot+be+cast+to+%5BB
[70]: /images/20220516/5b412767db6c47ce9044f50c9fea3fb7.png
[https_yq.aliyun.com_articles_236384_spm_a2c4e.11153940.blogcont236383.20.d17a1c96Lm3AHM_cc8]: https://yq.aliyun.com/articles/236384?spm=a2c4e.11153940.blogcont236383.20.d17a1c96Lm3AHM#cc8