一、创建会话

1. 创建一个基本的ZooKeeper会话实例

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.WatchedEvent;
  6. import org.apache.zookeeper.Watcher;
  7. import org.apache.zookeeper.ZooKeeper;
  8. import org.apache.zookeeper.Watcher.Event.KeeperState;
  9.  
  10. /**
  11.  * 创建一个基本的ZooKeeper会话实例
  12.  * @author  huey
  13.  * @version 1.0
  14.  * @created 2015-3-1
  15.  */
  16. public class ZKDemo {
  17.  
  18.     public static void main(String[] args) throws Exception {
  19.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  20.  
  21.         /**
  22.          * ZooKeeper客户端和服务器会话的建立是一个异步的过程
  23.          * 构造函数在处理完客户端的初始化工作后立即返回，在大多数情况下，并没有真正地建立好会话
  24.          * 当会话真正创建完毕后，Zookeeper服务器会向客户端发送一个事件通知
  25.          */
  26.         ZooKeeper zk = new ZooKeeper("192.168.1.109:2181", 5000, new Watcher() {
  27.             @Override
  28.             public void process(WatchedEvent event) {
  29.                 if (event.getState() == KeeperState.SyncConnected) {
  30.                     connectedSignal.countDown();
  31.                 }
  32.             }
  33.         });
  34.         System.out.println("State1: " + zk.getState());    // CONNECTING
  35.  
  36.         connectedSignal.await();
  37.         System.out.println("State2: " + zk.getState());    // CONNECTED
  38.  
  39.         zk.close();
  40.         System.out.println("State3: " + zk.getState());    // CLOSED
  41.     }
  42.  
  43. }

2. 创建一个复用sessionId和sessionPasswd的Zookeeper对象示例

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.WatchedEvent;
  6. import org.apache.zookeeper.Watcher;
  7. import org.apache.zookeeper.ZooKeeper;
  8. import org.apache.zookeeper.Watcher.Event.KeeperState;
  9.  
  10. /**
  11.  * 创建一个复用sessionId和sessionPasswd的ZooKeeper对象示例
  12.  * @author  huey
  13.  * @version 1.0
  14.  * @created 2015-3-1
  15.  */
  16. public class ZKDemo {
  17.  
  18.     public static void main(String[] args) throws Exception {
  19.  
  20.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  21.         ZooKeeper zk = new ZooKeeper("192.168.1.109:2181", 5000, new Watcher() {
  22.             @Override
  23.             public void process(WatchedEvent event) {
  24.                 if (event.getState() == KeeperState.SyncConnected) {
  25.                     connectedSignal.countDown();
  26.                 }
  27.             }
  28.         });
  29.  
  30.         connectedSignal.await();
  31.         long sessionId = zk.getSessionId();
  32.         byte[] passwd = zk.getSessionPasswd();
  33.         zk.close();
  34.  
  35.         final CountDownLatch anotherConnectedSignal = new CountDownLatch(1);
  36.         ZooKeeper newZk = new ZooKeeper(
  37.                 "192.168.1.109:2181",
  38.                 5000,
  39.                 new Watcher() {
  40.                     @Override
  41.                     public void process(WatchedEvent event) {
  42.                         if (event.getState() == KeeperState.SyncConnected) {
  43.                             anotherConnectedSignal.countDown();
  44.                         }
  45.                     }
  46.                 },
  47.                 sessionId,
  48.                 passwd);
  49.  
  50.         anotherConnectedSignal.await();
  51.         newZk.close();
  52.     }
  53.  
  54. }

二、创建节点

1. 使用同步API创建一个ZNode节点

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.CreateMode;
  6. import org.apache.zookeeper.WatchedEvent;
  7. import org.apache.zookeeper.Watcher;
  8. import org.apache.zookeeper.ZooKeeper;
  9. import org.apache.zookeeper.Watcher.Event.KeeperState;
  10. import org.apache.zookeeper.ZooDefs.Ids;
  11.  
  12. /**
  13.  * 使用同步API创建一个ZNode节点
  14.  * @author  huey
  15.  * @version 1.0
  16.  * @created 2015-3-1
  17.  */
  18. public class ZKDemo {
  19.  
  20.     public static void main(String[] args) throws Exception {
  21.  
  22.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  23.         ZooKeeper zk = new ZooKeeper("192.168.1.109:2181", 5000, new Watcher() {
  24.             @Override
  25.             public void process(WatchedEvent event) {
  26.                 if (event.getState() == KeeperState.SyncConnected) {
  27.                     connectedSignal.countDown();
  28.                 }
  29.             }
  30.         });
  31.         connectedSignal.await();
  32.  
  33.         String path = zk.create(
  34.                 "/zk-huey",
  35.                 "hello".getBytes(),
  36.                 Ids.OPEN_ACL_UNSAFE,
  37.                 CreateMode.PERSISTENT
  38.         );
  39.         System.out.println(path + " is created.");
  40.  
  41.         zk.close();
  42.     }
  43.  
  44. }

2. 使用异步API创建一个ZNode节点

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.AsyncCallback;
  6. import org.apache.zookeeper.CreateMode;
  7. import org.apache.zookeeper.WatchedEvent;
  8. import org.apache.zookeeper.Watcher;
  9. import org.apache.zookeeper.ZooKeeper;
  10. import org.apache.zookeeper.Watcher.Event.KeeperState;
  11. import org.apache.zookeeper.ZooDefs.Ids;
  12.  
  13. /**
  14.  * 使用异步API创建一个ZNode节点
  15.  * @author  huey
  16.  * @version 1.0
  17.  * @created 2015-3-1
  18.  */
  19. public class ZKDemo {
  20.  
  21.     public static void main(String[] args) throws Exception {
  22.  
  23.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  24.         ZooKeeper zk = new ZooKeeper("192.168.1.109:2181", 5000, new Watcher() {
  25.             @Override
  26.             public void process(WatchedEvent event) {
  27.                 if (event.getState() == KeeperState.SyncConnected) {
  28.                     connectedSignal.countDown();
  29.                 }
  30.             }
  31.         });
  32.         connectedSignal.await();
  33.  
  34.         zk.create(
  35.                 "/zk-huey",
  36.                 "hello".getBytes(),
  37.                 Ids.OPEN_ACL_UNSAFE,
  38.                 CreateMode.PERSISTENT_SEQUENTIAL,
  39.                 new AsyncCallback.StringCallback() {
  40.                     @Override
  41.                     public void processResult(int rc, String path, Object ctx, String name) {
  42.                         // 服务器响应吗
  43.                         System.out.println("ResultCode: " + rc);
  44.                         // 接口调用时传入API的数据节点的路径参数值
  45.                         System.out.println("Znode: " + path);
  46.                         // 接口调用时传入API的ctx参数值
  47.                         System.out.println("Context: " + (String)ctx);
  48.                         // 实际在服务端创建的节点名
  49.                         System.out.println("Real Path: " + name);
  50.                     }
  51.                 },
  52.                 "The Context"
  53.         );
  54.  
  55.         zk.close();
  56.     }
  57.  
  58. }

三、删除节点

1. 使用同API删除一个ZNode节点

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.WatchedEvent;
  6. import org.apache.zookeeper.Watcher;
  7. import org.apache.zookeeper.ZooKeeper;
  8. import org.apache.zookeeper.Watcher.Event.KeeperState;
  9.  
  10. /**
  11.  * 使用同步API删除一个ZNode节点
  12.  * @author  huey
  13.  * @version 1.0
  14.  * @created 2015-3-1
  15.  */
  16. public class ZKDemo {
  17.  
  18.     public static void main(String[] args) throws Exception {
  19.  
  20.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  21.         ZooKeeper zk = new ZooKeeper("192.168.1.109:2181", 5000, new Watcher() {
  22.             @Override
  23.             public void process(WatchedEvent event) {
  24.                 if (event.getState() == KeeperState.SyncConnected) {
  25.                     connectedSignal.countDown();
  26.                 }
  27.             }
  28.         });
  29.         connectedSignal.await();
  30.  
  31.         zk.delete("/zk-huey", -1);
  32.  
  33.         zk.close();
  34.     }
  35.  
  36. }

2. 使用异步API删除一个ZNode节点

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.AsyncCallback;
  6. import org.apache.zookeeper.WatchedEvent;
  7. import org.apache.zookeeper.Watcher;
  8. import org.apache.zookeeper.ZooKeeper;
  9. import org.apache.zookeeper.Watcher.Event.KeeperState;
  10.  
  11. /**
  12.  * 使用异步API删除一个ZNode节点
  13.  * @author  huey
  14.  * @version 1.0
  15.  * @created 2015-3-1
  16.  */
  17. public class ZKDemo {
  18.  
  19.     public static void main(String[] args) throws Exception {
  20.  
  21.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  22.         ZooKeeper zk = new ZooKeeper("192.168.1.109:2181", 5000, new Watcher() {
  23.             @Override
  24.             public void process(WatchedEvent event) {
  25.                 if (event.getState() == KeeperState.SyncConnected) {
  26.                     connectedSignal.countDown();
  27.                 }
  28.             }
  29.         });
  30.         connectedSignal.await();
  31.  
  32.         zk.delete(
  33.                 "/zk-huey",
  34.                 -1,
  35.                 new AsyncCallback.VoidCallback() {
  36.                     @Override
  37.                     public void processResult(int rc, String path, Object ctx) {
  38.                         System.out.println("ResultCode: " + rc);
  39.                         System.out.println("Znode: " + path);
  40.                         System.out.println("Context: " + (String)ctx);
  41.                     }
  42.                 },
  43.                 "The Context"
  44.         );
  45.  
  46.         zk.close();
  47.     }
  48.  
  49. }

四、获取子节点列表

1. 使用同步API获取子节点列表

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.List;
  4. import java.util.concurrent.CountDownLatch;
  5.  
  6. import org.apache.zookeeper.CreateMode;
  7. import org.apache.zookeeper.KeeperException;
  8. import org.apache.zookeeper.WatchedEvent;
  9. import org.apache.zookeeper.Watcher;
  10. import org.apache.zookeeper.ZooKeeper;
  11. import org.apache.zookeeper.Watcher.Event.EventType;
  12. import org.apache.zookeeper.Watcher.Event.KeeperState;
  13. import org.apache.zookeeper.ZooDefs.Ids;
  14. import org.apache.zookeeper.data.Stat;
  15.  
  16. /**
  17.  * 使用同步API获取子节点列表
  18.  * @author  huey
  19.  * @version 1.0
  20.  * @created 2015-3-1
  21.  */
  22. public class ZKDemo {
  23.  
  24.     public static void main(String[] args) throws Exception {
  25.  
  26.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  27.         final ZooKeeper zk = new ZooKeeper("192.168.1.109:2182", 5000, null);
  28.         zk.register(new Watcher() {
  29.             @Override
  30.             public void process(WatchedEvent event) {
  31.                 if (event.getState() == KeeperState.SyncConnected) {
  32.                     if (event.getType() == EventType.None
  33.                             && event.getPath() == null) {
  34.                         connectedSignal.countDown();
  35.                     } else if (event.getType() == EventType.NodeChildrenChanged) {
  36.                         try {
  37.                             System.out.println("NodeChildrenChanged.");
  38.                             List<String> children = zk.getChildren(event.getPath(), true);
  39.                             System.out.println("Children: " + children);
  40.                         } catch (KeeperException e) {
  41.                             e.printStackTrace();
  42.                         } catch (InterruptedException e) {
  43.                             e.printStackTrace();
  44.                         }
  45.                     }
  46.                 }
  47.             }
  48.         });
  49.         connectedSignal.await();
  50.  
  51.         zk.create("/zk-huey", "root".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  52.         zk.create("/zk-huey/node1", "node1".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  53.         zk.create("/zk-huey/node2", "node2".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  54.  
  55.         Stat stat = new Stat();
  56.         List<String> children = zk.getChildren("/zk-huey",
  57.                 true,    // 注册默认的Watcher，当子节点类别发送变更的话，向客户端发送通知
  58.                 stat    // 用于描述节点状态信息
  59.         );
  60.         System.out.println("Stat: " + stat);
  61.         System.out.println("Children: " + children);
  62.  
  63.         zk.create("/zk-huey/node3", "node3".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  64.  
  65.         Thread.sleep(10 * 1000);
  66.         zk.close();
  67.     }
  68.  
  69. }

结果输出：

  1. Stat: 4294967436,4294967436,1425201236879,1425201236879,0,2,0,0,4,2,4294967438
  2.  
  3. Children: [node2, node1]
  4. NodeChildrenChanged.
  5. State: CONNECTED
  6. Children: [node2, node3, node1]

2. 使用异步API获取子节点列表

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.List;
  4. import java.util.concurrent.CountDownLatch;
  5.  
  6. import org.apache.zookeeper.AsyncCallback;
  7. import org.apache.zookeeper.CreateMode;
  8. import org.apache.zookeeper.KeeperException;
  9. import org.apache.zookeeper.WatchedEvent;
  10. import org.apache.zookeeper.Watcher;
  11. import org.apache.zookeeper.ZooKeeper;
  12. import org.apache.zookeeper.Watcher.Event.EventType;
  13. import org.apache.zookeeper.Watcher.Event.KeeperState;
  14. import org.apache.zookeeper.ZooDefs.Ids;
  15. import org.apache.zookeeper.data.Stat;
  16.  
  17. /**
  18.  * 使用异步API获取子节点列表
  19.  * @author  huey
  20.  * @version 1.0
  21.  * @created 2015-3-1
  22.  */
  23. public class ZKDemo {
  24.  
  25.     public static void main(String[] args) throws Exception {
  26.  
  27.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  28.         final ZooKeeper zk = new ZooKeeper("192.168.1.109:2182", 5000, null);
  29.         zk.register(new Watcher() {
  30.             @Override
  31.             public void process(WatchedEvent event) {
  32.                 if (event.getState() == KeeperState.SyncConnected) {
  33.                     if (event.getType() == EventType.None
  34.                             && event.getPath() == null) {
  35.                         connectedSignal.countDown();
  36.                     } else if (event.getType() == EventType.NodeChildrenChanged) {
  37.                         try {
  38.                             System.out.println("NodeChildrenChanged.");
  39.                             List<String> children = zk.getChildren(event.getPath(), true);
  40.                             System.out.println("Children: " + children);
  41.                         } catch (KeeperException e) {
  42.                             e.printStackTrace();
  43.                         } catch (InterruptedException e) {
  44.                             e.printStackTrace();
  45.                         }
  46.                     }
  47.                 }
  48.             }
  49.         });
  50.         connectedSignal.await();
  51.  
  52.         zk.create("/zk-huey", "root".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  53.         zk.create("/zk-huey/node1", "node1".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  54.         zk.create("/zk-huey/node2", "node2".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  55.  
  56.         zk.getChildren("/zk-huey",
  57.                 true,
  58.                 new AsyncCallback.Children2Callback() {
  59.                     @Override
  60.                     public void processResult(int rc, String path, Object ctx,
  61.                             List<String> children, Stat stat) {
  62.                         System.out.println("ResultCode: " + rc);
  63.                         System.out.println("ZNode: " + path);
  64.                         System.out.println("Context: " + ctx);
  65.                         System.out.println("Children: " + children);
  66.                         System.out.println("Stat: " + stat);
  67.                     }
  68.                 },
  69.                 "The Context"
  70.         );
  71.  
  72.         zk.create("/zk-huey/node3", "node3".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  73.  
  74.         Thread.sleep(10 * 1000);
  75.         zk.close();
  76.     }
  77.  
  78. }

五、获取节点数据内容

1. 使用同步API获取节点数据内容

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.CreateMode;
  6. import org.apache.zookeeper.WatchedEvent;
  7. import org.apache.zookeeper.Watcher;
  8. import org.apache.zookeeper.ZooKeeper;
  9. import org.apache.zookeeper.Watcher.Event.EventType;
  10. import org.apache.zookeeper.Watcher.Event.KeeperState;
  11. import org.apache.zookeeper.ZooDefs.Ids;
  12.  
  13. /**
  14.  * 使用同步API获取节点数据内容
  15.  * @author  huey
  16.  * @version 1.0
  17.  * @created 2015-3-1
  18.  */
  19. public class ZKDemo {
  20.  
  21.     public static void main(String[] args) throws Exception {
  22.  
  23.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  24.         final ZooKeeper zk = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  25.             @Override
  26.             public void process(WatchedEvent event) {
  27.                 if (event.getState() == KeeperState.SyncConnected) {
  28.                     if (event.getType() == EventType.None
  29.                             && event.getPath() == null) {
  30.                         connectedSignal.countDown();
  31.                     }
  32.                 }
  33.             }
  34.         });
  35.         connectedSignal.await();
  36.  
  37.         zk.create("/zk-huey", "hello".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  38.         byte[] nodeData = zk.getData("/zk-huey", false, null);
  39.         System.out.println("NodeData: " + new String(nodeData));
  40.  
  41.         zk.close();
  42.     }
  43.  
  44. }

2. 使用异步API获取节点数据内容

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.AsyncCallback;
  6. import org.apache.zookeeper.CreateMode;
  7. import org.apache.zookeeper.WatchedEvent;
  8. import org.apache.zookeeper.Watcher;
  9. import org.apache.zookeeper.ZooKeeper;
  10. import org.apache.zookeeper.Watcher.Event.EventType;
  11. import org.apache.zookeeper.Watcher.Event.KeeperState;
  12. import org.apache.zookeeper.ZooDefs.Ids;
  13. import org.apache.zookeeper.data.Stat;
  14.  
  15. /**
  16.  * 使用异步API获取节点数据内容
  17.  * @author  huey
  18.  * @version 1.0
  19.  * @created 2015-3-1
  20.  */
  21. public class ZKDemo {
  22.  
  23.     public static void main(String[] args) throws Exception {
  24.  
  25.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  26.         final ZooKeeper zk = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  27.             @Override
  28.             public void process(WatchedEvent event) {
  29.                 if (event.getState() == KeeperState.SyncConnected) {
  30.                     if (event.getType() == EventType.None
  31.                             && event.getPath() == null) {
  32.                         connectedSignal.countDown();
  33.                     }
  34.                 }
  35.             }
  36.         });
  37.         connectedSignal.await();
  38.  
  39.         zk.create("/zk-huey", "hello".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  40.         zk.getData(
  41.                 "/zk-huey",
  42.                 false,
  43.                 new AsyncCallback.DataCallback() {
  44.                     @Override
  45.                     public void processResult(int rc, String path, Object ctx, byte[] data,
  46.                             Stat stat) {
  47.                         System.out.println("ResultCode: " + rc);
  48.                         System.out.println("ZNode: " + path);
  49.                         System.out.println("Context: " + ctx);
  50.                         System.out.println("NodeData: " + new String(data));
  51.                         System.out.println("Stat: " + stat);
  52.                     }
  53.                 },
  54.                 "The Context"
  55.         );
  56.  
  57.         zk.close();
  58.     }
  59.  
  60. }

六、更新数据

1. 使用同步API更新节点数据内容

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.CreateMode;
  6. import org.apache.zookeeper.WatchedEvent;
  7. import org.apache.zookeeper.Watcher;
  8. import org.apache.zookeeper.ZooKeeper;
  9. import org.apache.zookeeper.Watcher.Event.EventType;
  10. import org.apache.zookeeper.Watcher.Event.KeeperState;
  11. import org.apache.zookeeper.ZooDefs.Ids;
  12.  
  13. /**
  14.  * 使用同步API更新节点数据内容
  15.  * @author  huey
  16.  * @version 1.0
  17.  * @created 2015-3-1
  18.  */
  19. public class ZKDemo {
  20.  
  21.     public static void main(String[] args) throws Exception {
  22.  
  23.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  24.         final ZooKeeper zk = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  25.             @Override
  26.             public void process(WatchedEvent event) {
  27.                 if (event.getState() == KeeperState.SyncConnected) {
  28.                     if (event.getType() == EventType.None
  29.                             && event.getPath() == null) {
  30.                         connectedSignal.countDown();
  31.                     }
  32.                 }
  33.             }
  34.         });
  35.         connectedSignal.await();
  36.  
  37.         zk.create("/zk-huey", "hello".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  38.         byte[] nodeData = zk.getData("/zk-huey", false, null);
  39.         System.out.println("NodeData: " + nodeData);
  40.  
  41.         zk.setData("/zk-huey", "world".getBytes(), -1);
  42.         nodeData = zk.getData("/zk-huey", false, null);
  43.         System.out.println("NodeData: " + nodeData);
  44.  
  45.         zk.close();
  46.     }
  47.  
  48. }

2. 使用异步API更新节点数据内容

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.AsyncCallback;
  6. import org.apache.zookeeper.CreateMode;
  7. import org.apache.zookeeper.WatchedEvent;
  8. import org.apache.zookeeper.Watcher;
  9. import org.apache.zookeeper.ZooKeeper;
  10. import org.apache.zookeeper.Watcher.Event.EventType;
  11. import org.apache.zookeeper.Watcher.Event.KeeperState;
  12. import org.apache.zookeeper.ZooDefs.Ids;
  13. import org.apache.zookeeper.data.Stat;
  14.  
  15. /**
  16.  * 使用异步API更新节点数据内容
  17.  * @author  huey
  18.  * @version 1.0
  19.  * @created 2015-3-1
  20.  */
  21. public class ZKDemo {
  22.  
  23.     public static void main(String[] args) throws Exception {
  24.  
  25.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  26.         final ZooKeeper zk = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  27.             @Override
  28.             public void process(WatchedEvent event) {
  29.                 if (event.getState() == KeeperState.SyncConnected) {
  30.                     if (event.getType() == EventType.None
  31.                             && event.getPath() == null) {
  32.                         connectedSignal.countDown();
  33.                     }
  34.                 }
  35.             }
  36.         });
  37.         connectedSignal.await();
  38.  
  39.         zk.create("/zk-huey", "hello".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  40.         byte[] nodeData = zk.getData("/zk-huey", false, null);
  41.         System.out.println("NodeData: " + nodeData);
  42.  
  43.         zk.setData(
  44.                 "/zk-huey",
  45.                 "world".getBytes(),
  46.                 -1,
  47.                 new AsyncCallback.StatCallback() {
  48.                     @Override
  49.                     public void processResult(int rc, String path, Object ctx, Stat stat) {
  50.                         System.out.println("ResultCode: " + rc);
  51.                         System.out.println("ZNode: " + path);
  52.                         System.out.println("Context: " + ctx);
  53.                         System.out.println("Stat: " + stat);
  54.                     }
  55.                 },
  56.                 "The Context"
  57.         );
  58.  
  59.         zk.close();
  60.     }
  61.  
  62. }

七、判断节点是否存在

1. 使用同步API判断节点是否存在

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.AsyncCallback;
  6. import org.apache.zookeeper.CreateMode;
  7. import org.apache.zookeeper.WatchedEvent;
  8. import org.apache.zookeeper.Watcher;
  9. import org.apache.zookeeper.ZooKeeper;
  10. import org.apache.zookeeper.Watcher.Event.EventType;
  11. import org.apache.zookeeper.Watcher.Event.KeeperState;
  12. import org.apache.zookeeper.ZooDefs.Ids;
  13. import org.apache.zookeeper.data.Stat;
  14.  
  15. /**
  16.  * 使用同步API判断节点是否存在
  17.  * @author  huey
  18.  * @version 1.0
  19.  * @created 2015-3-1
  20.  */
  21. public class ZKDemo {
  22.  
  23.     public static void main(String[] args) throws Exception {
  24.  
  25.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  26.         final ZooKeeper zk = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  27.             @Override
  28.             public void process(WatchedEvent event) {
  29.                 if (event.getState() == KeeperState.SyncConnected) {
  30.                     if (event.getType() == EventType.None
  31.                             && event.getPath() == null) {
  32.                         connectedSignal.countDown();
  33.                     }
  34.                 }
  35.             }
  36.         });
  37.         connectedSignal.await();
  38.  
  39.         Stat stat = zk.exists("/zk-huey", false);
  40.         if (stat == null) {
  41.             zk.create("/zk-huey", "hello".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
  42.         } else {
  43.             System.out.println("Stat: " + stat);
  44.         }
  45.  
  46.         zk.close();
  47.     }
  48.  
  49. }

2. 使用异步API判断节点是否存在

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.AsyncCallback;
  6. import org.apache.zookeeper.WatchedEvent;
  7. import org.apache.zookeeper.Watcher;
  8. import org.apache.zookeeper.ZooKeeper;
  9. import org.apache.zookeeper.Watcher.Event.EventType;
  10. import org.apache.zookeeper.Watcher.Event.KeeperState;
  11. import org.apache.zookeeper.data.Stat;
  12.  
  13. /**
  14.  * 使用异步API判断节点是否存在
  15.  * @author  huey
  16.  * @version 1.0
  17.  * @created 2015-3-1
  18.  */
  19. public class ZKDemo {
  20.  
  21.     public static void main(String[] args) throws Exception {
  22.  
  23.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  24.         final ZooKeeper zk = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  25.             @Override
  26.             public void process(WatchedEvent event) {
  27.                 if (event.getState() == KeeperState.SyncConnected) {
  28.                     if (event.getType() == EventType.None
  29.                             && event.getPath() == null) {
  30.                         connectedSignal.countDown();
  31.                     }
  32.                 }
  33.             }
  34.         });
  35.         connectedSignal.await();
  36.  
  37.         zk.exists(
  38.                 "/zk-huey",
  39.                 false,
  40.                 new AsyncCallback.StatCallback() {
  41.                     @Override
  42.                     public void processResult(int rc, String path, Object ctx, Stat stat) {
  43.                         System.out.println("ResultCode: " + rc);
  44.                         System.out.println("ZNode: " + path);
  45.                         System.out.println("Context: " + ctx);
  46.                         System.out.println("Stat: " + stat);
  47.                     }
  48.                 },
  49.                 "The Context"
  50.         );
  51.  
  52.         zk.close();
  53.     }
  54.  
  55. }

八、权限控制

  1. package com.huey.dream.demo;
  2.  
  3. import java.util.concurrent.CountDownLatch;
  4.  
  5. import org.apache.zookeeper.CreateMode;
  6. import org.apache.zookeeper.WatchedEvent;
  7. import org.apache.zookeeper.Watcher;
  8. import org.apache.zookeeper.ZooKeeper;
  9. import org.apache.zookeeper.ZooDefs.Ids;
  10.  
  11. /**
  12.  * ZooKeeper权限控制
  13.  * @author  huey
  14.  * @version 1.0
  15.  * @created 2015-3-1
  16.  */
  17. public class ZKDemo {
  18.  
  19.     public static void main(String[] args) throws Exception {
  20.  
  21.         /**
  22.          * 使用含有权限信息的zookeeper会话创建数据节点
  23.          */
  24.         final CountDownLatch connectedSignal = new CountDownLatch(1);
  25.         ZooKeeper zk = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  26.             @Override
  27.             public void process(WatchedEvent event) {
  28.                 connectedSignal.countDown();
  29.             }
  30.         });
  31.         connectedSignal.await();
  32.         zk.addAuthInfo("digest", "huey:123".getBytes());
  33.         zk.create("/zk-huey", "hello".getBytes(), Ids.CREATOR_ALL_ACL, CreateMode.PERSISTENT);
  34.         zk.close();
  35.  
  36.         /**
  37.          * 使用无权限信息的zookeeper会话访问含有权限信息的数据节点
  38.          */
  39.         try {
  40.             final CountDownLatch signal = new CountDownLatch(1);
  41.             ZooKeeper zk1 = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  42.                 @Override
  43.                 public void process(WatchedEvent event) {
  44.                     signal.countDown();
  45.                 }
  46.             });
  47.             signal.await();
  48.             zk1.getData("/zk-huey", false, null);
  49.             System.out.println("NodeData: " + new String(zk1.getData("/zk-huey", false, null)));
  50.             zk1.close();
  51.         } catch (Exception e) {
  52.             System.out.println("Failed to delete Znode: " + e.getMessage());
  53.         }
  54.  
  55.         /**
  56.          * 使用错误权限信息的zookeeper会话访问含有权限信息的数据节点
  57.          */
  58.         try {
  59.             final CountDownLatch signal = new CountDownLatch(1);
  60.             ZooKeeper zk2 = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  61.                 @Override
  62.                 public void process(WatchedEvent event) {
  63.                     signal.countDown();
  64.                 }
  65.             });
  66.             signal.await();
  67.             zk2.addAuthInfo("digest", "huey:abc".getBytes());
  68.             System.out.println("NodeData: " + new String(zk2.getData("/zk-huey", false, null)));
  69.             zk2.close();
  70.         } catch (Exception e) {
  71.             System.out.println("Failed to delete Znode: " + e.getMessage());
  72.         }
  73.  
  74.         /**
  75.          * 使用正确权限信息的zookeeper会话访问含有权限信息的数据节点
  76.          */
  77.         try {
  78.             final CountDownLatch signal = new CountDownLatch(1);
  79.             ZooKeeper zk3 = new ZooKeeper("192.168.1.109:2182", 5000, new Watcher() {
  80.                 @Override
  81.                 public void process(WatchedEvent event) {
  82.                     signal.countDown();
  83.                 }
  84.             });
  85.             signal.await();
  86.             zk3.addAuthInfo("digest", "huey:123".getBytes());
  87.             System.out.println("NodeData: " + new String(zk3.getData("/zk-huey", false, null)));
  88.             zk3.close();
  89.         } catch (Exception e) {
  90.             System.out.println("Failed to delete Znode: " + e.getMessage());
  91.         }
  92.     }
  93.  
  94. }

结果输出：

  1. Failed to delete Znode: KeeperErrorCode = NoAuth for /zk-huey
  2. Failed to delete Znode: KeeperErrorCode = NoAuth for /zk-huey
  3. NodeData: hello

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