Zookeeper 服务注册与发现

服务注册

public class ServiceRegister {
    private static final String BASE_SERVICES = "/services";
    private static final String  SERVICE_NAME = "/products";

    public static void register(String address, int port) {
        try {
            ZooKeeper zooKeeper = new ZooKeeper("localhost:2181",5000,(watchedEvent)->{});
            Stat exists = zooKeeper.exists(BASE_SERVICES + SERVICE_NAME, false);
            if(exists==null) {
                zooKeeper.create(BASE_SERVICES + SERVICE_NAME,"".getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
            }
            String server_path = address+":"+port;
            // 临时节点，断网自动删除
            zooKeeper.create(BASE_SERVICES + SERVICE_NAME+"/child",server_path.getBytes(), ZooDefs.Ids.OPEN_ACL_UNSAFE,CreateMode.EPHEMERAL_SEQUENTIAL);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

服务发现

public class InitListener implements ServletContextListener {
    private  static final String BASE_SERVICES = "/services";
    private static final String  SERVICE_NAME="/products";
    private ZooKeeper zooKeeper;

    @Override
    public void contextInitialized(ServletContextEvent sce) {
        try {
             zooKeeper = new ZooKeeper("localhost:2181",5000,(watchedEvent)->{
                if(watchedEvent.getType() == Watcher.Event.EventType.NodeChildrenChanged  && watchedEvent.getPath().equals(BASE_SERVICES+SERVICE_NAME)) {
                    updateServiceList();
                }
            });

            updateServiceList();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private void updateServiceList() {
       try{
           List<String> children = zooKeeper.getChildren(BASE_SERVICES  + SERVICE_NAME, true);
           List<String> newServerList = new ArrayList<String>();
           for(String subNode:children) {
               byte[] data = zooKeeper.getData(BASE_SERVICES  + SERVICE_NAME + "/" + subNode, false, null);
               String host = new String(data, "utf-8");
               System.out.println("host:"+host);
               newServerList.add(host);
           }
           // 负载均衡
           LoadBalance.SERVICE_LIST = newServerList;
       }catch (Exception e) {
           e.printStackTrace();
       }
    }

    @Override
    public void contextDestroyed(ServletContextEvent sce) {}
}