【问题描述】

       今天在CDH集群中使用Flume的时候报了如下的错误：

2020-04-10 11:02:33,627 (conf-file-poller-0) [ERROR - org.apache.flume.node.PollingPropertiesFileConfigurationProvider$FileWatcherRunnable.run(PollingPropertiesFileConfigurationProvider.java:154)] Unhandled error
java.lang.NoSuchMethodError: org.apache.flume.Context.getSubProperties(Ljava/lang/String;)Lcom/google/common/collect/ImmutableMap;
	at org.keedio.flume.source.HibernateHelper.<init>(HibernateHelper.java:46)
	at org.keedio.flume.source.SQLSource.configure(SQLSource.java:72)
	at org.apache.flume.conf.Configurables.configure(Configurables.java:41)
	at org.apache.flume.node.AbstractConfigurationProvider.loadSources(AbstractConfigurationProvider.java:325)
	at org.apache.flume.node.AbstractConfigurationProvider.getConfiguration(AbstractConfigurationProvider.java:105)
	at org.apache.flume.node.PollingPropertiesFileConfigurationProvider$FileWatcherRunnable.run(PollingPropertiesFileConfigurationProvider.java:145)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

【问题原因】

       根据报错内容，可以发现原因是因为Flume中getSubProperties的返回类型不匹配。org.apache.flume.context类在flume-ng-configuration-1.9.0-cdh6.3.1.jar、flume-ng-configuration.jar包里面，查看这个两个jar包，里面都是有方法：public Map<String, String> getSubProperties(String prefix)：

  public Map<String, String> getSubProperties(String prefix)
  {
    Preconditions.checkArgument(prefix.endsWith("."), "The given prefix does not end with a period (" + prefix + ")");
    
    Map<String, String> result = Maps.newHashMap();
    synchronized (this.parameters)
    {
      for (Map.Entry<String, String> entry : this.parameters.entrySet())
      {
        String key = (String)entry.getKey();
        if (key.startsWith(prefix))
        {
          String name = key.substring(prefix.length());
          result.put(name, entry.getValue());
        }
      }
    }
    return ImmutableMap.copyOf(result);
  }

       而添加的flume-ng-sql-source jar包虽然也有这个方法，但是返回值类型不一样，这个jar包里面的方法返回值类型是ImmutableMap。

【解决办法】

       更换flume-ng-sql-source jar包，jar包可以点这里（链接：https://pan.baidu.com/s/13TcC4uyLtNLeFKAheA0Jqw 提取码：xnij）下载，此处的jar包返回值类型为Map。