Curator是Netflix公司开源的一个Zookeeper客户端，与Zookeeper提供的原生客户端相比，Curator的抽象层次更高，简化了Zookeeper客户端编程。
它包含以下几个组件：
| Component | description |
|---|---|
| Recipes | Implementations of some of the common ZooKeeper “recipes”. The implementations are built on top of the Curator Framework. |
| Framework | The Curator Framework is a high-level API that greatly simplifies using ZooKeeper. It adds many features that build on ZooKeeper and handles the complexity of managing connections to the ZooKeeper cluster and retrying operations. |
| Utilities | Various utilities that are useful when using ZooKeeper. |
| Client | A replacement for the bundled ZooKeeper class that takes care of some low-level housekeeping and provides some useful utilities. |
| Errors | How Curator deals with errors, connection issues, recoverable exceptions, etc. |
| Extensions | The curator-recipes package implements the common recipes that are described in the ZooKeeper documentation. To avoid bloating that package, recipes/applications that have a vertical appeal will be put in separate “extension” packages using the naming convention curator-x-name. |
示例：
<?xml version="1.0"?> <project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><modelVersion>4.0.0</modelVersion><groupId>com.sf.zkclient</groupId><artifactId>zkclient</artifactId><version>0.0.1-SNAPSHOT</version><name>zkclient</name><url>http://maven.apache.org</url><properties><curator.version>2.11.1</curator.version><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties><dependencies><dependency><groupId>org.apache.zookeeper</groupId><artifactId>zookeeper</artifactId><version>3.4.8</version><exclusions><exclusion><artifactId>slf4j-log4j12</artifactId><groupId>org.slf4j</groupId></exclusion><exclusion><artifactId>log4j</artifactId><groupId>log4j</groupId></exclusion></exclusions></dependency><dependency><groupId>org.apache.curator</groupId><artifactId>curator-framework</artifactId><version>${curator.version}</version></dependency><dependency><groupId>org.apache.curator</groupId><artifactId>curator-client</artifactId><version>${curator.version}</version><exclusions><exclusion><groupId>com.google.guava</groupId><artifactId>guava</artifactId></exclusion></exclusions></dependency><dependency><groupId>com.google.guava</groupId><artifactId>guava</artifactId><version>18.0</version></dependency> </dependencies> </project>
java代码：
示例一：常见的添加、修改、删除示例：
public static void test() throws Exception {String address = "localhost:2181";CuratorFramework client = CuratorFrameworkFactory.newClient(address, new ExponentialBackoffRetry(1000, 3));try{client.start();String path = "/yongjiu2/yongjiu3/test5";//a. 创建永久性节点 client.create().creatingParentContainersIfNeeded().withMode(CreateMode.PERSISTENT).withACL(ZooDefs.Ids.OPEN_ACL_UNSAFE).forPath(path, "hello, zk".getBytes());System.out.println("b");//b. 创建临时节点client.create().withMode(CreateMode.EPHEMERAL).forPath("/temptest5", "hello".getBytes()); System.out.println("c");//c.获取节点值byte[] buf = client.getData().forPath(path);System.out.println("get data path:"+path+", data:"+new String(buf));System.out.println("d");//d.设置节点值client.setData().inBackground().forPath(path, "ricky".getBytes());System.out.println("e");//e.checkExistsStat stat = client.checkExists().forPath(path);if(stat==null){System.out.println("exec create path:"+path);}else {System.out.println("exec getData");}System.out.println("f");//f.删除节点 client.delete().deletingChildrenIfNeeded().forPath(path);byte[] buf2 = client.getData().forPath(path);System.out.println("get data path:"+path+", data:"+new String(buf2));}finally {if(client!=null)client.close();}}
示例二：临时节点不能有子节点、不能级联创建示例：
/*** 级联创建临时节点测试，结果会创建不成功，报错* @throws Exception*/public static void test2() throws Exception {String address = "localhost:2181";CuratorFramework client = CuratorFrameworkFactory.newClient(address, new ExponentialBackoffRetry(1000, 3));try{client.start();String path = "/linshi";//b. 创建临时节点client.create().withMode(CreateMode.EPHEMERAL).forPath(path, "hello".getBytes()); byte[] buf = client.getData().forPath(path);System.out.println("get data path:"+path+", data:"+new String(buf));//Zookeeper创建临时节点的时候，不能创建级联的节点，下面的create会报错String path2 = "/linshi/test";//b. 创建临时节点client.create().withMode(CreateMode.EPHEMERAL).forPath(path2, "hello".getBytes()); //byte[] buf2 = client.getData().forPath(path2);//System.out.println("get data path:"+path2+", data:"+new String(buf2)); TimeUnit.SECONDS.sleep(100 * 1000);}finally {if(client!=null)client.close();}}
示例三：3、临时节点何时失效演示（在会话结束时被移除）
/*** 临时节点什么时候失效？是在本次会话结束时* @throws Exception*/public static void test3() throws Exception {String address = "localhost:2181";CuratorFramework client = CuratorFrameworkFactory.newClient(address, new ExponentialBackoffRetry(1000, 3));try{client.start();String path = "/linshi";//b. 创建临时节点client.create().withMode(CreateMode.EPHEMERAL).forPath(path, "hello".getBytes()); byte[] buf = client.getData().forPath(path);System.out.println("get data path:"+path+", data:"+new String(buf));TimeUnit.SECONDS.sleep(100 * 1000);}finally {if(client!=null)client.close();}}
