zookeeper動態上下線推送
阿新 • • 發佈:2019-02-16
package com.gcx.zookeeper2; import org.apache.zookeeper.CreateMode; import org.apache.zookeeper.WatchedEvent; import org.apache.zookeeper.Watcher; import org.apache.zookeeper.ZooDefs.Ids; import org.apache.zookeeper.ZooKeeper; public class DistributedServer { private static final String connectString ="192.168.48.156:2181,192.168.53.141:2181,192.168.48.154:2181"; private static final int sessionTimeout=60000; private static final String parentNode = "/servers"; private ZooKeeper zk = null; /** * 建立到zk的客戶端連線 * * @throws Exception */ public void getConnect() throws Exception { zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() { @Override public void process(WatchedEvent event) { // 收到事件通知後的回撥函式(應該是我們自己的事件處理邏輯) System.out.println(event.getType() + "---" + event.getPath()); try { zk.getChildren("/", true); } catch (Exception e) { } } }); } /** * 向zk叢集註冊伺服器資訊 * * @param hostname * @throws Exception */ public void registerServer(String hostname) throws Exception { String create = zk.create(parentNode + "/server", hostname.getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL); System.out.println(hostname + "is online.." + create); } /** * 業務功能 * * @throws InterruptedException */ public void handleBussiness(String hostname) throws InterruptedException { System.out.println(hostname + "start working....."); Thread.sleep(Long.MAX_VALUE); } public static void main(String[] args) throws Exception { // 獲取zk連線 DistributedServer server = new DistributedServer(); server.getConnect(); // 利用zk連線註冊伺服器資訊 server.registerServer(args[0]); // 啟動業務功能 server.handleBussiness(args[0]); } }
package com.gcx.zookeeper2; import java.util.ArrayList; import java.util.List; import org.apache.zookeeper.KeeperException; import org.apache.zookeeper.WatchedEvent; import org.apache.zookeeper.Watcher; import org.apache.zookeeper.ZooKeeper; public class DistributedClient { private static final String connectString ="192.168.48.156:2181,192.168.53.141:2181,192.168.48.154:2181"; private static final int sessionTimeout=60000; private static final String parentNode = "/servers"; // 注意:加volatile的意義何在? private volatile List<String> serverList; private ZooKeeper zk = null; /** * 建立到zk的客戶端連線 * * @throws Exception */ public void getConnect() throws Exception { zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() { @Override public void process(WatchedEvent event) { // 收到事件通知後的回撥函式(應該是我們自己的事件處理邏輯) try { //重新更新伺服器列表,並且註冊了監聽 getServerList(); } catch (Exception e) { } } }); } /** * 獲取伺服器資訊列表 * * @throws Exception */ public void getServerList() throws Exception { // 獲取伺服器子節點資訊,並且對父節點進行監聽 List<String> children = zk.getChildren(parentNode, true); // 先建立一個區域性的list來存伺服器資訊 List<String> servers = new ArrayList<String>(); for (String child : children) { // child只是子節點的節點名 byte[] data = zk.getData(parentNode + "/" + child, false, null); servers.add(new String(data)); } // 把servers賦值給成員變數serverList,已提供給各業務執行緒使用 serverList = servers; //列印伺服器列表 System.out.println(serverList); } /** * 業務功能 * * @throws InterruptedException */ public void handleBussiness() throws InterruptedException { System.out.println("client start working....."); Thread.sleep(Long.MAX_VALUE); } public static void main(String[] args) throws Exception { // 獲取zk連線 DistributedClient client = new DistributedClient(); client.getConnect(); // 獲取servers的子節點資訊(並監聽),從中獲取伺服器資訊列表 client.getServerList(); // 業務執行緒啟動 client.handleBussiness(); } }