zookeeperAPI

zookeeper API示例

http://zookeeper.apache.org/doc/r3.4.6/api/index.html

zookeeper API示例

zookeeper代码示例：

import java.io.IOException;
import java.util.List;

import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooKeeper;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper.States;

/**
 * Zookeeper 工具类
 * 
 */
public class ZookeeperClient {

/*
 * comma separated host:port pairs, each corresponding to a zk <p> server.
 * e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002"
 */
public static final String ZOOKEEPER_CONNECTION_STRING = "hadoop-zengjr.xiaoqee.com:2181,"//
        + "hadoop-slave01.xiaoqee.com:2181,"//
        + "hadoop-slave02.xiaoqee.com:2181";

public static final int ZOOKEEPER_CONNECTION_TIMEOUT = 2000;

public static final int ZOOKEEPER_VERSION = -1;

/**
 * 获取Zookeeper链接
 * 
 * @return
 * @throws IOException
 * @throws InterruptedException
 */
public static ZooKeeper getZookeeper() {
    ZooKeeper zooKeeper = null;
    try {
        // 创建一个与服务器的连接
        zooKeeper = new ZooKeeper( //
                ZOOKEEPER_CONNECTION_STRING, ZOOKEEPER_CONNECTION_TIMEOUT, //
                new Watcher() { // 监控所有被触发的事件
                    @Override
                    public void process(WatchedEvent event) {
                        // 打印事件的名称
                        System.out.println(event.toString());
                    }
                }//
        );

        // 等待连接
        while (zooKeeper.getState() != States.CONNECTED) {
            Thread.sleep(20);
        }

    } catch (Exception e) {
        e.printStackTrace();
    }
    return zooKeeper;
}

/**
 * 关闭连接
 * 
 * @param zooKeeper
 */
public static void closeZookeeper(ZooKeeper zooKeeper) {
    if (null != zooKeeper) {
        try {
            zooKeeper.close();
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

/**
 * 判断目录节点是否存在
 * 
 * @param nodePath
 *      节点的路径,如/psb
 * @return
 *      false表示节点不存在,true表示存在
 */
public static boolean isExists(String nodePath) {
    // 获取Zookeeper链接
    ZooKeeper zooKeeper = getZookeeper();

    try {
        // 判断节点是否存在
        return (null == zooKeeper.exists(nodePath, true)) ? false : true;
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (null != zooKeeper) {
            closeZookeeper(zooKeeper);
        }
    }
    return false;
}

/**
 * 创建节点
 * 
 * @param nodePath
 *            节点的路径,如/psb,目录一级一级的创建,不能一下创建多级节点目录
 * @param nodeData
 *            节点的数据
 * @param createMode
 *            节点的类型,有四种类型:PERSISTENT,PERSISTENT_SEQUENTIAL,EPHEMERAL,
 *            EPHEMERAL_SEQUENTIAL
 */
public static void createNode(String nodePath, String nodeData,
        CreateMode createMode) {
    ZooKeeper zooKeeper = getZookeeper();

    try {
        // 判断节点是否存在
        boolean exists = isExists(nodePath);

        // 创建节点目录
        if (!exists) {
            zooKeeper.create(//
                    nodePath,//
                    nodeData.getBytes(),//
                    Ids.OPEN_ACL_UNSAFE, //
                    createMode);
        } else {
            System.out.println("[" + nodePath + "] 已经存在!");
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (null != zooKeeper) {
            closeZookeeper(zooKeeper);
        }
    }
}

/**
 * 获取目录节点的数据
 * 
 * @param zooKeeper
 * @param nodePath
 * @throws KeeperException
 * @throws InterruptedException
 */
public static String getNodeData(String nodePath) {
    ZooKeeper zooKeeper = getZookeeper();
    try {

        byte[] bytes = zooKeeper.getData(nodePath, false, null);
        String data = new String(bytes);
        return data;
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (null != zooKeeper) {
            closeZookeeper(zooKeeper);
        }
    }
    return "";
}

/**
 *  设置目录节点的数据
 * 
 * @param zooKeeper
 * @param nodePath
 * @throws KeeperException
 * @throws InterruptedException
 */
public static void setNodeData(String nodePath,String nodeData) {
    ZooKeeper zooKeeper = getZookeeper();
    try {
        // 修改节点数据
        zooKeeper.setData(nodePath,//
                nodeData.getBytes(),//
                ZOOKEEPER_VERSION);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (null != zooKeeper) {
            closeZookeeper(zooKeeper);
        }
    }
}

/**
 * 获取某个节点下面的所有子节点（属于儿子级别的）
 * 
 * @param nodePath
 * @return
 */
public static List<String> getChildrenNodes(String nodePath) {
    ZooKeeper zooKeeper = getZookeeper();
    try {
        // 获取目录节点的所有子节点
        return zooKeeper.getChildren(nodePath, true);
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (null != zooKeeper) {
            closeZookeeper(zooKeeper);
        }
    }
    return null;
}

/**
 * 刪除节点
 * 
 * @param nodePath
 */
public static void deleteNode(String nodePath) {
    ZooKeeper zooKeeper = getZookeeper();
    try {
        // 判断节点是否存在
        boolean exists = isExists(nodePath);

        if(exists){
            // 删除节点
            zooKeeper.delete(nodePath,ZOOKEEPER_VERSION);
        }
    } catch (Exception e) {
        e.printStackTrace();
    } finally {
        if (null != zooKeeper) {
            closeZookeeper(zooKeeper);
        }
    }
}

// 测试
public static void main(String[] args) {
    // createNode("/psb", "服务总线", CreateMode.PERSISTENT);
    // createNode("/test/hello", "测", CreateMode.PERSISTENT);

    // System.out.println(getNodeData("/psb"));;

    //  System.out.println(getChildrenNodes("/"));;
    //  deleteNode("/psb");
}
}