分布式锁实现（一）使用ZooKeeper+Curator

@SpringBootApplication
public class CuratorApplication implements InitializingBean, DisposableBean {

    private AtomicInteger atomicInteger;
    private ExecutorService executorService;

    @Autowired
    private CuratorFramework curatorFramework;

    public static void main(String[] args) {
        CuratorApplication app = SpringApplication.run(CuratorApplication.class, args).getBean(CuratorApplication.class);
        app.tryCuratorLock();
    }

    private void tryCuratorLock() {
        final Map<String, Long> t = new HashMap<String, Long>() {{
            put("st", System.currentTimeMillis());
        }};
        Runnable r = () -> {
            while(true) {
                int calls = atomicInteger.incrementAndGet();
                try {
                    interProcessMutex();
                } catch (Exception e) {
                    e.printStackTrace();
                }
                if (calls % 1000 == 0) {
                    long et = System.currentTimeMillis();
                    long st = t.get("st");
                    System.out.println("call " + calls + " times, consume: "+ (et-st));
                    t.put("st", et);
                }
            }
        };
        for (int i=0; i<15; i++) {
            executorService.submit(r);
        }
    }
    
    private void interProcessMutex() throws Exception {
        InterProcessMutex interProcessMutex = new InterProcessMutex(curatorFramework, "/lock-path");
        try {
            interProcessMutex.acquire();
            // Do nothing
        } finally {
            interProcessMutex.release();
        }
    }

    @Override
    public void afterPropertiesSet() throws Exception {
        this.atomicInteger = new AtomicInteger();
        this.executorService = Executors.newFixedThreadPool(15);
    }

    @Override
    public void destroy() throws Exception {
        this.executorService.shutdown();
    }
}

@Configuration
public class CuratorConfiguration {

    @Autowired
    CuratorConfigurationProperties curatorConfiguration;

    @Bean
    public CuratorFramework curatorFramework() {
        RetryPolicy retryPolicy = new RetryNTimes(curatorConfiguration.getRetryCount(), curatorConfiguration.getElapsedTimeMs());
        CuratorFramework curatorFramework = CuratorFrameworkFactory.builder()
            .connectString(curatorConfiguration.getConnectString())
            .sessionTimeoutMs(curatorConfiguration.getSessionTimeoutMs())
            .connectionTimeoutMs(curatorConfiguration.getConnectionTimeoutMs())
            .retryPolicy(retryPolicy)
        .build();
        return curatorFramework;
    }
}

curator.retryCount=5
curator.elapsedTimeMs=5000
#curator.connectString=localhost:2181
curator.connectString=172.22.122.21:2181,172.22.122.21:2182,172.22.122.21:2183
curator.sessionTimeoutMs=60000
curator.connectionTimeoutMs=5000

我们用一个空业务逻辑来进行锁的性能测试：

call 1000 times, consume: 6273
call 2000 times, consume: 6073
call 3000 times, consume: 6184
call 4000 times, consume: 6200
call 5000 times, consume: 5996
call 6000 times, consume: 6333
call 7000 times, consume: 6185
call 8000 times, consume: 6159
call 9000 times, consume: 7171

平均一千次调用需要花费6秒左右，这还仅仅是3点的Zk集群，如果点数更多，同步时间更长，吞吐量会更低