ZooKeeper Connection Loss 异常
原因:一般是由于连接还未完成就执行zookeeper的get/create/exsit操作引起的.
解决方法:
利用"CountDownLatch 类 + zookeeper的watcher + zookeeper的getStat" 实现连接完成后再调用.
可防止此错误发生.
示例类如下(为一配置获取类):
viewplaincopy
[*]import java.util.concurrent.CountDownLatch;
[*]
[*]
[*]import org.apache.zookeeper.WatchedEvent;
[*]import org.apache.zookeeper.Watcher;
[*]import org.apache.zookeeper.Watcher.Event.KeeperState;
[*]import org.apache.zookeeper.ZooKeeper;
[*]import org.apache.zookeeper.ZooKeeper.States;
[*]import org.apache.zookeeper.data.Stat;
[*]public class Conf{
[*] public static void waitUntilConnected(ZooKeeper zooKeeper, CountDownLatch connectedLatch) {
[*] if (States.CONNECTING == zooKeeper.getState()) {
[*] try {
[*] connectedLatch.await();
[*] } catch (InterruptedException e) {
[*] throw new IllegalStateException(e);
[*] }
[*] }
[*] }
[*]
[*] static class ConnectedWatcher implements Watcher {
[*]
[*] private CountDownLatch connectedLatch;
[*]
[*] ConnectedWatcher(CountDownLatch connectedLatch) {
[*] this.connectedLatch = connectedLatch;
[*] }
[*]
[*] @Override
[*] public void process(WatchedEvent event) {
[*] if (event.getState() == KeeperState.SyncConnected) {
[*] connectedLatch.countDown();
[*] }
[*] }
[*] }
[*] static public Conf Instance(){
[*] if(static_ == null){
[*] static_ = new Conf();
[*] }
[*] return static_;
[*] }
[*] public boolean Init(String hostports, int times){
[*] try{
[*] CountDownLatch connectedLatch = new CountDownLatch(1);
[*] Watcher watcher = new ConnectedWatcher(connectedLatch);
[*] zk_ = new ZooKeeper(hostports, times, watcher);
[*] waitUntilConnected(zk_, connectedLatch);
[*] }
[*] catch(Exception e){
[*] System.out.println(e);
[*] return false;
[*] }
[*] return true;
[*] }
[*] public String Get(String keys){
[*] String re = "";
[*] String ppath = "/zookeeper";
[*] int oldpos = -1;
[*] int pos = 0;
[*] while(true){
[*] pos = keys.indexOf(".", oldpos + 1);
[*] if(pos < 0){
[*] ppath += "/";
[*] String str = keys.substring(oldpos + 1);
[*] ppath += str;
[*] break;
[*] }
[*] ppath += "/";
[*] String str = keys.substring(oldpos + 1,pos);
[*] ppath += str;
[*] oldpos = pos;
[*] }
[*] Stat stat = new Stat();
[*] try{
[*] byte[] b = zk_.getData(ppath, false, stat); //获取节点的信息及存储的数据
[*] re = new String(b);
[*] }
[*] catch(Exception e){
[*] System.out.println(e);
[*] }
[*] return re;
[*] }
[*] private Conf(){
[*]
[*] }
[*] private ZooKeeper zk_;
[*] static private Conf static_;
[*] public static void main(String args[]){
[*] String hostports = "192.168.1.88:2181,192.168.1.88:2182,192.168.1.88:2183";
[*]
[*] Conf.Instance().Init(hostports, 1000);
[*]
[*] String str = Conf.Instance().Get("conf.logicpoint.subscriberserverip");
[*] str = Conf.Instance().Get("conf.logicpoint.subscriberserverport");
[*] System.out.println(str);
[*] while(true){
[*] try{Thread.sleep(100);}
[*] catch(Exception e){
[*]
[*] }
[*] }
[*]
[*] }
[*]}
页:
[1]