canal与kafka的zkclient版本冲突

摘要: canal与kafka的zkclient版本冲突，导致canal客户端连接服务端时，报AbstractMethodError错误。

9553 [main] ERROR c.a.o.c.c.i.r.ClientRunningMonitor - There is an error when execute initRunning method, with destination [example].
java.lang.AbstractMethodError: com.alibaba.otter.canal.common.zookeeper.ZooKeeperx.writeDataReturnStat(Ljava/lang/String;[BI)Lorg/apache/zookeeper/data/Stat;
at org.I0Itec.zkclient.ZkClient$10.call(ZkClient.java:817) ~[zkclient-0.3.jar:0.3]
at org.I0Itec.zkclient.ZkClient.retryUntilConnected(ZkClient.java:675) ~[zkclient-0.3.jar:0.3]
at org.I0Itec.zkclient.ZkClient.writeDataReturnStat(ZkClient.java:813) ~[zkclient-0.3.jar:0.3]
at org.I0Itec.zkclient.ZkClient.writeData(ZkClient.java:808) ~[zkclient-0.3.jar:0.3]
at org.I0Itec.zkclient.ZkClient.writeData(ZkClient.java:777) ~[zkclient-0.3.jar:0.3]
at com.alibaba.otter.canal.client.impl.running.ClientRunningMonitor.processActiveEnter(ClientRunningMonitor.java:215) [canal.client-1.0.22.jar:na]
at com.alibaba.otter.canal.client.impl.running.ClientRunningMonitor.initRunning(ClientRunningMonitor.java:118) [canal.client-1.0.22.jar:na]
at com.alibaba.otter.canal.client.impl.running.ClientRunningMonitor.start(ClientRunningMonitor.java:92) [canal.client-1.0.22.jar:na]
at com.alibaba.otter.canal.client.impl.SimpleCanalConnector.connect(SimpleCanalConnector.java:93) [canal.client-1.0.22.jar:na]
at com.alibaba.otter.canal.client.impl.ClusterCanalConnector.connect(ClusterCanalConnector.java:63) [canal.client-1.0.22.jar:na]
at com.alibaba.otter.canal.client.CanalConnector$connect.call(Unknown Source) [canal.client-1.0.22.jar:na]

canal版本：1.0.22；kafka版本：0.8.2.1；客户端通过CanalConnectors.newClusterConnector(String zkServers, String destination, String username,String password)方法连接canal集群。

错误原因：canal依赖的zkclient版本为0.1;kafka依赖的zkclient版本为0.3；

0.3版本的zkclient在调用writeData方法时，会调用IZkConnection实现类ZooKeeperx（canal.common包）的writeDataReturnStat方法，而canal.client包因为是依赖0.1版本，ZooKeeperx并没有writeDataReturnStat方法。

所以当classloader加载的是0.3版本，调用writeData时，在ZooKeeperx类找不到writeDataReturnStat方法，报AbstractMethodError错误，最终导致连接canal服务端失败。

解决步骤：

canal父工程zkclient版本升级为0.3

<dependency>
<artifactId>zkclient</artifactId>
<groupId>com.101tec</groupId>
<version>0.3</version>
<!--
<groupId>com.github.sgroschupf</groupId>
<artifactId>zkclient</artifactId>
<version>0.1</version>
-->
</dependency>

ZooKeeperx（com.alibaba.otter.canal.common.zookeeper包下）实现writeDataReturnStat方法。

@Override
public Stat writeDataReturnStat(String path, byte[] data, int expectedVersion)
throws KeeperException, InterruptedException {
_zk.setData(path, data, expectedVersion);
return _zk.exists(path, false);
}

重新打canal.common包。完成，^_^