zookeeper 分布式锁

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zookeeper 分布式锁

 

实现原理：多个进程在同一个目录节点下注册临时顺序节点，节点顺序最小则获得锁，否则进行等待；当获取锁的进程运行结束释放锁或者故障临时节点自动删除时，其余进程可尝试获取锁

 

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引入 jar 包

 

<dependency>
    <groupId>org.apache.curator</groupId>
    <artifactId>curator-recipes</artifactId>
    <version>4.2.0</version>
</dependency>

 

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相关类

 

public class InterProcessMutex implements InterProcessLock, Revocable<InterProcessMutex> 

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构造方法

    public InterProcessMutex(CuratorFramework client, String path)

    public InterProcessMutex(CuratorFramework client, String path, LockInternalsDriver driver)


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常用方法

    public void acquire() throws Exception   //获得锁
    public boolean acquire(long time, TimeUnit unit) throws Exception
                                             //指定时间间隔内获取锁

    public void release() throws Exception   //释放锁

 

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使用示例

 

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config 层

 

@Configuration
public class ZookeeperConfig {

    @Value("${zookeeper.connecting-string}")
    private String connectingString;

    @Bean
    public CuratorFramework initCuratorFramework(){
        CuratorFramework curatorFramework= CuratorFrameworkFactory.builder()
                .connectString(connectingString)
                .sessionTimeoutMs(5000)
                .retryPolicy(new ExponentialBackoffRetry(1000,3,3000))
                .namespace("test")
                .build();
        curatorFramework.start();

        return curatorFramework;
    }
}

 

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controller 层

 

@RestController
public class HelloController {

    @Autowired
    private CuratorFramework curatorFramework;

    private String lockPath="/lock";

    @RequestMapping("/test")
    public String hello(){
        InterProcessMutex mutex=new InterProcessMutex(curatorFramework,lockPath);
        ExecutorService executorService= Executors.newFixedThreadPool(5);
        for(int i=0;i<5;i++){
            executorService.submit(() -> {
                try{
                    mutex.acquire();
                    System.out.println(Thread.currentThread().getId()+"获得锁"+System.currentTimeMillis());
                    Thread.sleep(1000);
                    System.out.println(Thread.currentThread().getId()+"执行完毕");
                }catch (Exception e){
                    e.printStackTrace();
                }finally {
                    try{
                        System.out.println(Thread.currentThread().getId()+"释放锁"+System.currentTimeMillis());
                        System.out.println();
                        mutex.release();
                    }catch (Exception e){
                        e.printStackTrace();
                    }
                }
            });
        }

        return "success";
    }
}

 

 

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控制台输出

 

70获得锁1569155723666
70执行完毕
70释放锁1569155724666

67获得锁1569155724688
67执行完毕
67释放锁1569155725693

69获得锁1569155725703
69执行完毕
69释放锁1569155726705

68获得锁1569155726720
68执行完毕
68释放锁1569155727722

71获得锁1569155727726
71执行完毕
71释放锁1569155728729