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Java客户端使用zookeeper api

2020-01-13 08:27 113 查看

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
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