Java客户端使用zookeeper api

添加zookeeper依赖

<!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->
<dependency>
    <groupId>org.apache.zookeeper</groupId>
    <artifactId>zookeeper</artifactId>
    <version>3.5.6</version>
</dependency>

创建会话

Zookeeper类提供了以下的构造方法，无论使用哪一个构造方法都可以顺利的创建会话。

 	public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher) throws java.io.IOException { /* compiled code */ }

    public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher, org.apache.zookeeper.client.ZKClientConfig conf) throws java.io.IOException { /* compiled code */ }

    public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher, boolean canBeReadOnly, org.apache.zookeeper.client.HostProvider aHostProvider) throws java.io.IOException { /* compiled code */ }

    public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher, boolean canBeReadOnly, org.apache.zookeeper.client.HostProvider aHostProvider, org.apache.zookeeper.client.ZKClientConfig clientConfig) throws java.io.IOException { /* compiled code */ }

    public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher, boolean canBeReadOnly) throws java.io.IOException { /* compiled code */ }

    public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher, boolean canBeReadOnly, org.apache.zookeeper.client.ZKClientConfig conf) throws java.io.IOException { /* compiled code */ }

    public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher, long sessionId, byte[] sessionPasswd) throws java.io.IOException { /* compiled code */ }

    public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher, long sessionId, byte[] sessionPasswd, boolean canBeReadOnly, org.apache.zookeeper.client.HostProvider aHostProvider) throws java.io.IOException { /* compiled code */ }

    public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher, long sessionId, byte[] sessionPasswd, boolean canBeReadOnly, org.apache.zookeeper.client.HostProvider aHostProvider, org.apache.zookeeper.client.ZKClientConfig clientConfig) throws java.io.IOException { /* compiled code */ }

    public ZooKeeper(java.lang.String connectString, int sessionTimeout, org.apache.zookeeper.Watcher watcher, long sessionId, byte[] sessionPasswd, boolean canBeReadOnly) throws java.io.IOException { /* compiled code */ }

• connectString：指定ZooKeeper服务器列表，有英文状态逗号分开的host:port组成的字符串，例如“192.168.44.130:2181,192.168.44.132:2181,192.168.44.133:2181”。
• sessionTimout：会话超时时间，以“毫秒”为单位的整数，zookeeper客户端和服务端通过心跳检测的方式保持会话的有效性，指定sessionTimout之后，在这一段时间内，没有进行有效的心跳检测，会话就会失效。
• watcher：定义事件接受的Watcher，可以设置为null，表示不监听。
• canBeReadOnly：boolean型的值，默认情况下，zookeeper只要有过半服务器主机失去网络连接，就不会再处理客户端的操作（读或者写），添加该属性则表示，在出现这种情况时，我们依旧可以使用读服务。
• sessionId和sessionPasswd：代表会话ID和秘钥，这两个参数可以确定唯一会话，可以做到复活会话的效果。

创建节点

    public java.lang.String create(java.lang.String path, byte[] data, java.util.List<org.apache.zookeeper.data.ACL> acl, org.apache.zookeeper.CreateMode createMode) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public void create(java.lang.String path, byte[] data, java.util.List<org.apache.zookeeper.data.ACL> acl, org.apache.zookeeper.CreateMode createMode, org.apache.zookeeper.AsyncCallback.StringCallback cb, java.lang.Object ctx) { /* compiled code */ }

• path：节点路径
• data[]：节点数据
• acl：acl策略
• createMode：节点类型
  • 持久 RERSISTENT
  • 持久序列化 PERSISTENT_SEQUENTIAL
  • 临时 EPHEMERAL
  • 临时序列化 EPHEMERAL_SEQUENTIAL
• cb：异步回调函数，服务器节点创建完毕之后，自动调用该方法
• ctx：可传入一个对象，该对象可以在回调方法中使用

删除节点

public void delete(java.lang.String path, int version) throws java.lang.InterruptedException, org.apache.zookeeper.KeeperException { /* compiled code */ }
public void delete(java.lang.String path, int version, org.apache.zookeeper.AsyncCallback.VoidCallback cb, java.lang.Object ctx) { /* compiled code */ }

• path：节点路径
• version：数据版本
• cb：异步回调函数，服务器节点创建完毕之后，自动调用该方法
• ctx：可传入一个对象，该对象可以在回调方法中使用

读取数据

读取数据包括对子节点的读取还有节点数据的读取。

getChildren

public java.util.List<java.lang.String> getChildren(java.lang.String path, org.apache.zookeeper.Watcher watcher) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public java.util.List<java.lang.String> getChildren(java.lang.String path, boolean watch) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public void getChildren(java.lang.String path, org.apache.zookeeper.Watcher watcher, org.apache.zookeeper.AsyncCallback.ChildrenCallback cb, java.lang.Object ctx) { /* compiled code */ }

    public void getChildren(java.lang.String path, boolean watch, org.apache.zookeeper.AsyncCallback.ChildrenCallback cb, java.lang.Object ctx) { /* compiled code */ }

    public java.util.List<java.lang.String> getChildren(java.lang.String path, org.apache.zookeeper.Watcher watcher, org.apache.zookeeper.data.Stat stat) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public java.util.List<java.lang.String> getChildren(java.lang.String path, boolean watch, org.apache.zookeeper.data.Stat stat) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public void getChildren(java.lang.String path, org.apache.zookeeper.Watcher watcher, org.apache.zookeeper.AsyncCallback.Children2Callback cb, java.lang.Object ctx) { /* compiled code */ }

    public void getChildren(java.lang.String path, boolean watch, org.apache.zookeeper.AsyncCallback.Children2Callback cb, java.lang.Object ctx) { /* compiled code */ }

• path：节点路径
• watcher：注册的watcher，子节点列表改变时，会触发
• watch：表明是否需要注册一个watcher
• cb：异步回调函数，服务器节点创建完毕之后，自动调用该方法
• ctx：可传入一个对象，该对象可以在回调方法中使用
• stat：指定节点的节点状态信息，服务器会响应新的stat对象替换

getData

    public byte[] getData(java.lang.String path, org.apache.zookeeper.Watcher watcher, org.apache.zookeeper.data.Stat stat) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public byte[] getData(java.lang.String path, boolean watch, org.apache.zookeeper.data.Stat stat) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public void getData(java.lang.String path, org.apache.zookeeper.Watcher watcher, org.apache.zookeeper.AsyncCallback.DataCallback cb, java.lang.Object ctx) { /* compiled code */ }

    public void getData(java.lang.String path, boolean watch, org.apache.zookeeper.AsyncCallback.DataCallback cb, java.lang.Object ctx) { /* compiled code */ }

• path：节点路径
• watcher：注册的watcher，子节点列表改变时，会触发
• watch：表明是否需要注册一个watcher
• cb：异步回调函数，服务器节点创建完毕之后，自动调用该方法
• ctx：可传入一个对象，该对象可以在回调方法中使用
• stat：指定节点的节点状态信息，服务器会响应新的stat对象替换

更新数据

  public org.apache.zookeeper.data.Stat setData(java.lang.String path, byte[] data, int version) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public void setData(java.lang.String path, byte[] data, int version, org.apache.zookeeper.AsyncCallback.StatCallback cb, java.lang.Object ctx) { /* compiled code */ }

• path：节点路径
• data[]：节点数据
• version：数据版本
• cb：异步回调函数，服务器节点创建完毕之后，自动调用该方法
• ctx：可传入一个对象，该对象可以在回调方法中使用

检测节点是否存在

	public org.apache.zookeeper.data.Stat exists(java.lang.String path, org.apache.zookeeper.Watcher watcher) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public org.apache.zookeeper.data.Stat exists(java.lang.String path, boolean watch) throws org.apache.zookeeper.KeeperException, java.lang.InterruptedException { /* compiled code */ }

    public void exists(java.lang.String path, org.apache.zookeeper.Watcher watcher, org.apache.zookeeper.AsyncCallback.StatCallback cb, java.lang.Object ctx) { /* compiled code */ }

    public void exists(java.lang.String path, boolean watch, org.apache.zookeeper.AsyncCallback.StatCallback cb, java.lang.Object ctx) { /* compiled code */ }

• path：节点路径
• watcher：注册的watcher，子节点列表改变时，会触发
• watch：表明是否需要注册一个watcher
• cb：异步回调函数，服务器节点创建完毕之后，自动调用该方法
• ctx：可传入一个对象，该对象可以在回调方法中使用

来源：CSDN

作者：一只小P熊

链接：https://blog.csdn.net/solo_jm/article/details/103720298