使用zookeeper实现集群和负载均衡

package com.bubble.cluster;

import java.net.InetSocketAddress;
import java.util.List;
import java.util.Random;
import java.util.concurrent.Executors;

import org.I0Itec.zkclient.IZkChildListener;
import org.I0Itec.zkclient.ZkClient;
import org.jboss.netty.bootstrap.ClientBootstrap;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;
import org.jboss.netty.handler.codec.string.StringDecoder;
import org.jboss.netty.handler.codec.string.StringEncoder;

/**
 * @author [email protected]
 * @date 2013-2-10
 */
public class Client extends ClusterClient {
	private static String appServer;
	private static String zkServer = "127.0.0.1:2181";
	private static ClientBootstrap bootstrap;
	private static Client client;

	public static void main(String[] args) throws Exception {

		ChannelFactory factory = new NioClientSocketChannelFactory(Executors.newCachedThreadPool(), Executors.newCachedThreadPool());
		bootstrap = new ClientBootstrap(factory);
		bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
			public ChannelPipeline getPipeline() {
				ChannelPipeline pipeline = Channels.pipeline();
				pipeline.addLast("encode", new StringEncoder());
				pipeline.addLast("decode", new StringDecoder());
				pipeline.addLast("handler", new DemoHandler());
				return pipeline;
			}
		});
		bootstrap.setOption("tcpNoDelay", true);
		bootstrap.setOption("keepAlive", true);
	    client=new Client();
	    ZkClient zkClient = new ZkClient(zkServer);
		client.connect(zkClient);
		
		client.failOver();
	}

	@Override
	public void connect(ZkClient zkClient) {
		while (true) {
			try {
				RoundRobinLoadBalance loadBlance = new RoundRobinLoadBalance();
				//loadBlance.SetClient("127.0.0.1:"+new Random().nextInt(1000));
				String server = loadBlance.select(zkServer);
				if (server != null) {
					String ip = server.split(":")[0];
					int port = Integer.parseInt(server.split(":")[1]);
					appServer = server;
					System.out.println(server);
					bootstrap.connect(new InetSocketAddress(ip, port));
					
					client.setZkClient(zkClient);
					client.join( "127.0.0.1:"+new Random().nextInt(5000));
					ZookeeperConnStatistic.incrementConn(zkServer, appServer);
					break;
				}
				Thread.sleep(1000);

			} catch (Exception e) {
				e.printStackTrace();
				try {
					Thread.sleep(1000);
				} catch (InterruptedException e1) {

				}
				connect(zkClient);
			}
		}

	}

package com.bubble.cluster;

import java.util.List;

import org.I0Itec.zkclient.IZkChildListener;
import org.I0Itec.zkclient.ZkClient;

/**
 * @author [email protected]
 * @date 2013-2-11
 */
public abstract class ClusterClient {
	public abstract void connect(ZkClient zkClient);
	public abstract String getAPPServer();
	public void setZkClient(ZkClient zkClient){
		this.zkClient=zkClient;
	}
    private ZkClient zkClient;

	public void failOver() {
		zkClient.subscribeChildChanges(Constant.root, new IZkChildListener() {
			@Override
			public void handleChildChange(String parentPath, List currentChilds) throws Exception {
				boolean has = false;
				for (int i = 0; i < currentChilds.size(); i++) {
					if (getAPPServer().equals(currentChilds.get(i))) {
						has = true;
						break;
					}
				}
				if (!has) {
					connect(zkClient);
				}
			}
		});
	}
	
	public void join(String client){
		if(!zkClient.exists(Constant.client)){
			zkClient.createPersistent(Constant.client);
		}
		if(!zkClient.exists(Constant.client+"/"+client)){
			zkClient.createEphemeral(Constant.client+"/"+client);
		}
	}
	
	public void leave(String client){		
		if(zkClient.exists(Constant.client+"/"+client)){
			zkClient.delete(Constant.client+"/"+client);
		}
		zkClient.close();
	}
}

package com.bubble.cluster;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.List;

import org.I0Itec.zkclient.ZkClient;

/**
 * @author [email protected]
 * @date 2013-2-11
 */
public class ConsistentHashLoadBalance implements LoadBlance {
	private String client;
	
	public void SetClient(String client){
		this.client=client;
	}
	
	@Override
	public String select(String zkServer) {
		ZkClient zkClient = new ZkClient(zkServer);
		List<String> serverList = zkClient.getChildren(Constant.root);
		ConsistentHashSelector selector=new ConsistentHashSelector(client,serverList);
		return selector.select();
		
	}
	
	 private static final class ConsistentHashSelector {
		 	public ConsistentHashSelector(String client,List<String> appServer){
		 		this.client=client;
		 		this.appServer=appServer;
		 	}
		 
		 	private String client;
		 	private List<String> appServer;
		 	
	        public String select() {
	            String key =client ;
	            byte[] digest = md5(key);
	            String server =appServer.get((int) hash(digest, 0));
	            return server;
	        }

	        private long hash(byte[] digest, int number) {
	            return (((long) (digest[3 + number * 4] & 0xFF) << 24)
	                    | ((long) (digest[2 + number * 4] & 0xFF) << 16)
	                    | ((long) (digest[1 + number * 4] & 0xFF) << 8) 
	                    | (digest[0 + number * 4] & 0xFF)) 
	                    & 0xFFFFFFFFL;
	        }

	        private byte[] md5(String value) {
	            MessageDigest md5;
	            try {
	                md5 = MessageDigest.getInstance("MD5");
	            } catch (NoSuchAlgorithmException e) {
	                throw new IllegalStateException(e.getMessage(), e);
	            }
	            md5.reset();
	            byte[] bytes = null;
	            try {
	                bytes = value.getBytes("UTF-8");
	            } catch (UnsupportedEncodingException e) {
	                throw new IllegalStateException(e.getMessage(), e);
	            }
	            md5.update(bytes);
	            return md5.digest();
	        }

	    }

}

package com.bubble.cluster;
/**
 * @author [email protected]
 * @date 2013-2-11
 */
public class Constant {
	public static final String root="/cluster";
	public static final String round="/round";
	public static final String client="/client";
	public static final String route="/route";
}

package com.bubble.cluster;

import java.util.Date;

import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelUpstreamHandler;

/**
 * @author [email protected]
 * @date 2013-2-10
 */
public class DemoHandler extends SimpleChannelUpstreamHandler {

	@Override
	public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
		Thread.sleep(5000);
		System.out.println(e.getMessage());
		ctx.getChannel().write("bbb");
	}
	@Override
    public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) {
        e.getChannel().write("abcd");
    }


}

package com.bubble.cluster;

import java.util.List;

import org.I0Itec.zkclient.ZkClient;

/**
 * @author [email protected]
 * @date 2013-2-11
 */
public class LeastActiveLoadBalance implements LoadBlance {

	@Override
	public String select(String zkServer) {
		ZkClient zkClient = new ZkClient(zkServer);
		List<String> serverList = zkClient.getChildren(Constant.root);

		String tempServer = null;
		int tempConn = -1;
		for (int i = 0; i < serverList.size(); i++) {
			String server = serverList.get(i);
			if (zkClient.readData(Constant.root + "/" + server) != null) {
				int connNum = zkClient.readData(Constant.root + "/" + server);
				if (tempConn == -1) {
					tempServer = server;
					tempConn = connNum;
				}
				if (connNum < tempConn) {
					tempServer = server;
					tempConn = connNum;
				}
			}else{
				zkClient.close();
				return server;
			}
		}
		zkClient.close();
		if (tempServer != null && !tempServer.equals("")) {
			return tempServer;
		}

		return null;
	}

}

package com.bubble.cluster;

import java.util.List;

/**
 * @author [email protected]
 * @date 2013-2-11
 */
public interface LoadBlance {
	String select(String zkServer);
}

package com.bubble.cluster;

import java.util.List;
import java.util.Random;

import org.I0Itec.zkclient.ZkClient;

/**
 * @author [email protected]
 * @date 2013-2-11
 */
public class RandomLoadBalance implements LoadBlance {

	@Override
	public String select(String zkServer) {
	    ZkClient zkClient = new ZkClient(zkServer);
		List<String> serverList = zkClient.getChildren(Constant.root);
		zkClient.close();
		Random r=new Random();
		if(serverList.size()>=1){
			String server=serverList.get(r.nextInt(serverList.size()));
			return server;
		}else{
			return null;
		}
		
	}

}

package com.bubble.cluster;

import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

import org.I0Itec.zkclient.ZkClient;

/**
 * @author [email protected]
 * @date 2013-2-11
 */
public class RoundRobinLoadBalance implements LoadBlance {
	
	@Override
	public String select(String zkServer) {
		ZkClient zkClient = new ZkClient(zkServer);
		List<String> serverList = zkClient.getChildren(Constant.root);
		int round=0;
		if(!zkClient.exists(Constant.round)){
			zkClient.createPersistent(Constant.round);
			zkClient.writeData(Constant.round, 0);
		}else{
			round=(Integer)zkClient.readData(Constant.round);
			zkClient.writeData(Constant.round, ++round);
		}
		zkClient.close();
		if (serverList != null && serverList.size() > 0) {
			return serverList.get(round % serverList.size());
		} else {
			return null;
		}

	}

}

package com.bubble.cluster;

import java.net.InetSocketAddress;
import java.util.concurrent.Executors;

import org.I0Itec.zkclient.ZkClient;
import org.apache.zookeeper.Watcher.Event.KeeperState;
import org.jboss.netty.bootstrap.ServerBootstrap;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
import org.jboss.netty.handler.codec.string.StringDecoder;
import org.jboss.netty.handler.codec.string.StringEncoder;

/**
 * @author [email protected]
 * @date 2013-2-10
 */
public class Server {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		ChannelFactory factory = new NioServerSocketChannelFactory(
	            Executors.newCachedThreadPool(),
	            Executors.newCachedThreadPool());
	        ServerBootstrap bootstrap = new ServerBootstrap (factory);
	        bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
	            public ChannelPipeline getPipeline() {
	                 ChannelPipeline pipeline = Channels.pipeline();
	                pipeline.addLast("encode",new StringEncoder());
	                pipeline.addLast("decode",new StringDecoder());
	                pipeline.addLast("handler",new DemoHandler());
	                return pipeline;
	            }
	        });
	        bootstrap.setOption("child.tcpNoDelay", true);
	        bootstrap.setOption("child.keepAlive", true);
	        bootstrap.bind(new InetSocketAddress(8081));
	        
	        ClusterServer.join("127.0.0.1:8081", "127.0.0.1:2181");
	}

}

package com.bubble.cluster;

import java.util.List;

import org.I0Itec.zkclient.ZkClient;

/**
 * @author [email protected]
 * @date 2013-2-11
 */
public class ZookeeperConnStatistic {
	public static void incrementConn(String zkServer,String appServer){
		ZkClient zkClient = new ZkClient(zkServer);
		List<String> serverList = zkClient.getChildren(Constant.root);
		for(int i=0;i<serverList.size();i++){
			String server=serverList.get(i);
			if(server.equals(appServer)){
				if(zkClient.readData(Constant.root+"/"+appServer)==null){
					zkClient.writeData(Constant.root+"/"+appServer, 1);	
				}else{
					int conn=zkClient.readData(Constant.root+"/"+appServer);
					zkClient.writeData(Constant.root+"/"+appServer, ++conn);
				}
				break;
			}
		}
		zkClient.close();
	}
	
	public static int getNodeConn(String zkServer,String appServer){
		ZkClient zkClient = new ZkClient(zkServer);
		List<String> serverList = zkClient.getChildren(Constant.root);
		for(int i=0;i<serverList.size();i++){
			String server=serverList.get(i);
			if(server.equals(appServer)){
				int conn=zkClient.readData(Constant.root+"/"+appServer);
				zkClient.close();
				return conn;
			}
		}
		zkClient.close();
		return 0;
	}
}

@Overridepublic String getAPPServer() {return appServer;}}