zookeeper的分布式唯一id生成器

之前已簡單介紹過Curator用戶端的使用，并利用Curator實作了分布式鎖和master選舉，文章連結：https://blog.csdn.net/fanrenxiang/article/details/83013218 本文簡述分庫分表之後分布式下如何保證ID全局唯一性，可以用普通的UUID來實作，但是UUID是雜亂無規律的，相反，我們利用zookeeper的持久順序節點特性，多個用戶端同時建立同一節點，zk保證了能有序的建立，建立成功并傳回的path類似于/root/generateid0000000001醬紫的，可以看到是順序有規律的，能較好的解決這個問題，缺點是，會依賴于zk。

maven 依賴

<dependency>
    <groupId>org.apache.zookeeper</groupId>
	<artifactId>zookeeper</artifactId>
	<version>3.4.12</version>
</dependency>
<dependency>
	<groupId>org.apache.curator</groupId>
	<artifactId>curator-framework</artifactId>
	<version>2.8.0</version>
</dependency>
<dependency>
	<groupId>org.apache.curator</groupId>
	<artifactId>curator-recipes</artifactId>
	<version>2.8.0</version>
</dependency>
           

實作類：

import org.apache.curator.RetryPolicy;
import org.apache.curator.framework.CuratorFramework;
import org.apache.curator.framework.CuratorFrameworkFactory;
import org.apache.curator.retry.ExponentialBackoffRetry;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.data.Stat;
import org.springframework.stereotype.Component;
 
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
 
/**
 * 類描述：分布式唯一ID生成器
 * <p>
 * 建立人：ternence
 */
@Component
public class DistributedIdGeneraterService {
 
    private static CuratorFramework curatorFrameworkClient;
 
    private static RetryPolicy retryPolicy;
 
    private static ExecutorService executorService;
 
    private static String IP_TOSTRING = "47.74.214.10:2181,47.74.214.10:2182,47.74.214.10:2183";
 
    private static String ROOT = "/root";
 
    private static String NODE_NAME = "idgenerator";
 
    static {
    	// 0 000 000 004
        retryPolicy = new ExponentialBackoffRetry(1000, 3);
        curatorFrameworkClient = CuratorFrameworkFactory
                .builder()
                .connectString(IP_TOSTRING)
                .sessionTimeoutMs(5000)
                .connectionTimeoutMs(5000)
                .retryPolicy(retryPolicy)
                .build();
        curatorFrameworkClient.start();
        try {
            executorService = Executors.newFixedThreadPool(10);
            //請先判斷父節點/root節點是否存在
            Stat stat = curatorFrameworkClient.checkExists().forPath(ROOT);
            if (stat == null) {
                curatorFrameworkClient.create().withMode(CreateMode.PERSISTENT).forPath(ROOT, null);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    public  String generateId() {
        String backPath = "";
 
        String fullPath = ROOT.concat("/").concat(NODE_NAME);
        try {
            // 關鍵點：建立持久順序節點
            backPath = curatorFrameworkClient.create().withMode(CreateMode.PERSISTENT_SEQUENTIAL).forPath(fullPath, null);
            //為防止生成的節點浪費系統資源，故生成後異步删除此節點
            String finalBackPath = backPath;
            executorService.execute(() -> {
                try {
                    curatorFrameworkClient.delete().forPath(finalBackPath);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            });
            String ID = splitID(backPath);
            System.out.println("生成的ID=" + ID);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return backPath;
    }
 
    public  String splitID(String path) {
        int index = path.lastIndexOf(NODE_NAME);
        if (index >= 0) {
            index += NODE_NAME.length();
            return index <= path.length() ? path.substring(index) : "";
        }
        return path;
    }
}
           

test:

private @Autowired DistributedIdGeneraterService bean;
System.out.println(bean.splitID(bean.generateId()));
           

輸出結果：

生成的ID=0000000006

0000000006

注意:報錯的解決方案

C:\Windows\System32\drivers\etc\hosts 裡加入 ip