Java多进程与ZooKeeper服务发现

在Java中实现多进程与ZooKeeper服务发现通常需要使用ZooKeeper客户端库来与ZooKeeper集群进行交互。以下是一个简单的示例代码，演示如何在Java中实现多进程与ZooKeeper服务发现：

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;

import java.util.List;

public class ZooKeeperServiceDiscovery {

    private static final String ZOOKEEPER_HOST = "localhost:2181";
    private static final String SERVICE_PATH = "/services";

    private ZooKeeper zooKeeper;

    public ZooKeeperServiceDiscovery() throws Exception {
        zooKeeper = new ZooKeeper(ZOOKEEPER_HOST, 5000, new Watcher() {
            @Override
            public void process(WatchedEvent event) {
                // Handle ZooKeeper events
            }
        });
    }

    public void registerService(String serviceName, String serviceAddress) throws Exception {
        String serviceNode = SERVICE_PATH + "/" + serviceName;
        if (zooKeeper.exists(serviceNode, false) == null) {
            zooKeeper.create(serviceNode, serviceAddress.getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL);
        }
    }

    public List<String> discoverServices(String serviceName) throws Exception {
        String serviceNode = SERVICE_PATH + "/" + serviceName;
        return zooKeeper.getChildren(serviceNode, false);
    }

    public void close() throws Exception {
        zooKeeper.close();
    }

    public static void main(String[] args) throws Exception {
        ZooKeeperServiceDiscovery discovery = new ZooKeeperServiceDiscovery();
        
        // Register a service
        discovery.registerService("exampleService", "localhost:8080");
        
        // Discover services
        List<String> services = discovery.discoverServices("exampleService");
        for (String service : services) {
            System.out.println("Discovered service: " + service);
        }
        
        discovery.close();
    }

}

在上面的示例中，我们首先创建了一个ZooKeeperServiceDiscovery类，该类封装了与ZooKeeper的交互操作。在main方法中，我们创建了一个ZooKeeperServiceDiscovery实例，并使用registerService方法注册了一个服务，并使用discoverServices方法发现了该服务。最后关闭了ZooKeeper连接。

需要注意的是，ZooKeeper服务发现在实际项目中常常结合使用其他框架或工具来实现更复杂的功能，比如使用Spring Cloud等。同时，需要确保ZooKeeper集群的正常运行，并考虑一些异常情况的处理。