Zookeeper之javaAPI的使用-蒲公英云

Zookeeper之javaAPI的使用

桃扇骨 2022-10-02 00:53 71阅读 0赞

2019独角兽企业重金招聘Python工程师标准>>>

Java程序操作Zookeeper

1.创建java项目并导入相关jar包

主要jar包在主目录下在这里插入图片描述项目需要的相关依赖的jar包在zookeeper的解压文件的lib目录下就有将这几个jar包导入项目中

<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.4.6</version>
    <type>pom</type>
</dependency>
<dependency>
    <groupId>com.github.sgroschupf</groupId>
    <artifactId>zkclient</artifactId>
    <version>0.1</version>
</dependency>
<dependency>
    <groupId>junit</groupId>
    <artifactId>junit</artifactId>
    <version>4.12</version>
</dependency>

API简单使用

2.1配置Zookeeper对象

// zookeeper的服务器地址,配置conf是用主机名，这里一样
    private String connectString ="zek00:2181,zek01:2181,zek02:2181";
    // 连接超时时间
    private int sessionTimeout = 2000;
    private ZooKeeper zk = null;
    /**
     * 设置zookeeper对象
     * @throws IOException 
     */
    @Before
    public void setZookeeper() throws IOException {
        zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
            /**
             * 事件触发的回调方法
             */
            @Override
            public void process(WatchedEvent event) {
            }
        });
        System.out.println("---"+zk);
    }

常用API操作

/**
 * create 方法参数
 *    第一个参数 路径
 *    第二个参数  值  bytes
 *    第三个参数  对节点的访问控制
 *    第四个参数  节点的类型 短暂  永久  序号        
 * @throws KeeperException
 * @throws InterruptedException
 */
@Test
public void create() throws KeeperException, InterruptedException {
    String path = zk.create("/app3", "123".getBytes(), 
            Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
    System.out.println(path);
}
/**
 * 判断节点是否存在
 * @throws InterruptedException 
 * @throws KeeperException 
 */
@Test
public void exist() throws KeeperException, InterruptedException{
    // 设置为 true 会调用 zk中的监听器
    Stat stat = zk.exists("/app1", true);
    if(stat!=null){
        System.out.println("存在。。。。"+stat.getDataLength());
    }else{
        System.out.println("不存在。。。");
    }
}
/**
 * 获取子节点
 * @throws InterruptedException 
 * @throws KeeperException 
 */
@Test
public void getChilren() throws KeeperException, InterruptedException{
    List<String> list = zk.getChildren("/", true);
    for (String s : list) {
        System.out.println(s);
    }
}
/**
 * 获取节点的内容
 * @throws InterruptedException 
 * @throws KeeperException 
 */
@Test
public void getData() throws KeeperException, InterruptedException{
    byte[] b = zk.getData("/app1", false, null );
    System.out.println(new String(b));
}
/**
 * 修改节点内容
 *       version -1 自动维护
 * @throws InterruptedException 
 * @throws KeeperException 
 */
@Test
public void setData() throws KeeperException, InterruptedException{
    Stat s = zk.setData("/app1", "test".getBytes(), -1);
}
/**
 * 删除节点
 *    非空节点删除不掉
 * @throws InterruptedException
 * @throws KeeperException
 */
@Test
public void deleteNode() throws InterruptedException, KeeperException{
    zk.delete("/app1", -1);
}

监听器的使用

@Before
public static void setUpBeforeClass() throws Exception {
    zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() {
        /**
         * 监听器
         */
        @Override
        public void process(WatchedEvent event) {
            System.out.println("事件触发...");
        }
    });
}
/**
 * 获取子节点
 * getChildren(path,watch?)监听的事件是：节点下的子节点增减变化事件
 * @throws InterruptedException 
 * @throws KeeperException 
 */
@Test
public void getChilren() throws KeeperException, InterruptedException{
    List<String> list = zk.getChildren("/", new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            // TODO Auto-generated method stub
            System.out.println("监控节点下的子节点被改变..."+event.getPath());
        }
    });
    for (String s : list) {
        System.out.println(s);
    }
    Thread.sleep(Long.MAX_VALUE);
}
/**
 * 获取节点的内容
 * getData(path,watch?)监听的事件是：节点数据变化事件
 * @throws InterruptedException 
 * @throws KeeperException 
 */
@Test
public void getData() throws KeeperException, InterruptedException{
    byte[] b = zk.getData("/app1", new Watcher() {
        @Override
        public void process(WatchedEvent event) {
            System.out.println("--数据改变了--");
        }
    }, null );
    System.out.println(new String(b));
    Thread.sleep(Long.MAX_VALUE);
}