Zookeeper学习(十)：ZooKeeper 实现分布式队列

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1.分布式队列的架构

2.向队列中提交数据流程

3.从队列中取数据流程

队列的组成

package com.jike.queue;import java.util.Collections;import java.util.Comparator;import java.util.List;import org.I0Itec.zkclient.ExceptionUtil;import org.I0Itec.zkclient.ZkClient;import org.I0Itec.zkclient.exception.ZkNoNodeException;public class DistributedSimpleQueue<T> {protected final ZkClient zkClient;//用于操作zookeeper集群protected final String root;//代表根节点protected static final String Node_NAME = "n_";//顺序节点的名称public DistributedSimpleQueue(ZkClient zkClient, String root) {this.zkClient = zkClient;this.root = root;}    //获取队列的大小public int size() {/** * 通过获取根节点下的子节点列表 */return zkClient.getChildren(root).size();}    //判断队列是否为空public boolean isEmpty() {return zkClient.getChildren(root).size() == 0;}/** * 向队列提供数据 * @param element * @return * @throws Exception */    public boolean offer(T element) throws Exception{        //构建数据节点的完整路径    String nodeFullPath = root .concat( "/" ).concat( Node_NAME );        try {        //创建持久的节点，写入数据            zkClient.createPersistentSequential(nodeFullPath , element);        }catch (ZkNoNodeException e) {        zkClient.createPersistent(root);        offer(element);        } catch (Exception e) {            throw ExceptionUtil.convertToRuntimeException(e);        }        return true;    }    //从队列取数据@SuppressWarnings("unchecked")public T poll() throws Exception {try {List<String> list = zkClient.getChildren(root);if (list.size() == 0) {return null;}//将队列安装由小到大的顺序排序Collections.sort(list, new Comparator<String>() {public int compare(String lhs, String rhs) {return getNodeNumber(lhs, Node_NAME).compareTo(getNodeNumber(rhs, Node_NAME));}});/** * 将队列中的元素做循环，然后构建完整的路径，在通过这个路径去读取数据 */for ( String nodeName : list ){String nodeFullPath = root.concat("/").concat(nodeName);try {T node = (T) zkClient.readData(nodeFullPath);zkClient.delete(nodeFullPath);return node;} catch (ZkNoNodeException e) {// ignore}}return null;} catch (Exception e) {throw ExceptionUtil.convertToRuntimeException(e);}}private String getNodeNumber(String str, String nodeName) {int index = str.lastIndexOf(nodeName);if (index >= 0) {index += Node_NAME.length();return index <= str.length() ? str.substring(index) : "";}return str;}}

发送的消息对象封装

package com.jike.queue;import java.io.Serializable;public class User implements Serializable {String name;String id;public String getName() {return name;}public void setName(String name) {this.name = name;}public String getId() {return id;}public void setId(String id) {this.id = id;}}

Zookeeper构建分布式队列测试

package com.jike.queue;import org.I0Itec.zkclient.ZkClient;import org.I0Itec.zkclient.serialize.SerializableSerializer;public class TestDistributedSimpleQueue {public static void main(String[] args) {ZkClient zkClient = new ZkClient("192.168.1.105:2181", 5000, 5000, new SerializableSerializer());DistributedSimpleQueue<User> queue = new DistributedSimpleQueue<User>(zkClient,"/Queue");User user1 = new User();user1.setId("1");user1.setName("xiao wang");User user2 = new User();user2.setId("2");user2.setName("xiao wang");try {queue.offer(user1);queue.offer(user2);User u1 = (User) queue.poll();User u2 = (User) queue.poll();if (user1.getId().equals(u1.getId()) && user2.getId().equals(u2.getId())){System.out.println("Success!");}} catch (Exception e) {e.printStackTrace();}}}

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