spring cloud微服務雲架構-用java使用 redlock

一、 在pom檔案引入redis和redisson依賴：

<!-- redis-->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-data-redis</artifactId>
		</dependency>
		<!-- redisson-->
		<dependency>
			<groupId>org.redisson</groupId>
			<artifactId>redisson</artifactId>
			<version>3.3.2</version>
		</dependency>

AquiredLockWorker介面類，，主要是用於獲取鎖後需要處理的邏輯：

/**
 * Created by fangzhipeng on 2017/4/5.
 * 獲取鎖後需要處理的邏輯
 */
public interface AquiredLockWorker<T> {
     T invokeAfterLockAquire() throws Exception;
}

二、DistributedLocker 獲取鎖管理類：

/**
 * Created by fangzhipeng on 2017/4/5.
 * 獲取鎖管理類
 */
public interface DistributedLocker {
     /**
      * 獲取鎖
      * @param resourceName  鎖的名稱
      * @param worker 獲取鎖後的處理類
      * @param <T>
      * @return 處理完具體的業務邏輯要返回的資料
      * @throws UnableToAquireLockException
      * @throws Exception
      */
     <T> T lock(String resourceName, AquiredLockWorker<T> worker) throws UnableToAquireLockException, Exception;
     <T> T lock(String resourceName, AquiredLockWorker<T> worker, int lockTime) throws UnableToAquireLockException, Exception;
}

nableToAquireLockException ，不能獲取鎖的異常類：

/**
 * Created by fangzhipeng on 2017/4/5.
 * 異常類
 */
public class UnableToAquireLockException extends RuntimeException {
    public UnableToAquireLockException() {
    }
    public UnableToAquireLockException(String message) {
        super(message);
    }
    public UnableToAquireLockException(String message, Throwable cause) {
        super(message, cause);
    }
}

三、RedissonConnector 連線類：

/**
 * Created by fangzhipeng on 2017/4/5.
 * 獲取RedissonClient連線類
 */
@Component
public class RedissonConnector {
    RedissonClient redisson;
    @PostConstruct
    public void init(){
        redisson = Redisson.create();
    }
    public RedissonClient getClient(){
        return redisson;
    }
}

四、RedisLocker 類，實現了DistributedLocker：

import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.util.concurrent.TimeUnit;
/**
 * Created by fangzhipeng on 2017/4/5.
 */
@Component
public class RedisLocker  implements DistributedLocker{
    private final static String LOCKER_PREFIX = "lock:";
    @Autowired
    RedissonConnector redissonConnector;
    @Override
    public <T> T lock(String resourceName, AquiredLockWorker<T> worker) throws InterruptedException, UnableToAquireLockException, Exception {
        return lock(resourceName, worker, 100);
    }
    @Override
    public <T> T lock(String resourceName, AquiredLockWorker<T> worker, int lockTime) throws UnableToAquireLockException, Exception {
        RedissonClient redisson= redissonConnector.getClient();
        RLock lock = redisson.getLock(LOCKER_PREFIX + resourceName);
      // Wait for 100 seconds seconds and automatically unlock it after lockTime seconds
        boolean success = lock.tryLock(100, lockTime, TimeUnit.SECONDS);
        if (success) {
            try {
                return worker.invokeAfterLockAquire();
            } finally {
                lock.unlock();
            }
        }
        throw new UnableToAquireLockException();
    }
}

五、測試類：

 

 @Autowired
    RedisLocker distributedLocker;
    @RequestMapping(value = "/redlock")
    public String testRedlock() throws Exception{
        CountDownLatch startSignal = new CountDownLatch(1);
        CountDownLatch doneSignal = new CountDownLatch(5);
        for (int i = 0; i < 5; ++i) { // create and start threads
            new Thread(new Worker(startSignal, doneSignal)).start();
        }
        startSignal.countDown(); // let all threads proceed
        doneSignal.await();
        System.out.println("All processors done. Shutdown connection");
        return "redlock";
    }
     class Worker implements Runnable {
        private final CountDownLatch startSignal;
        private final CountDownLatch doneSignal;
        Worker(CountDownLatch startSignal, CountDownLatch doneSignal) {
            this.startSignal = startSignal;
            this.doneSignal = doneSignal;
        }
        public void run() {
            try {
                startSignal.await();
                distributedLocker.lock("test",new AquiredLockWorker<Object>() {
                    @Override
                    public Object invokeAfterLockAquire() {
                        doTask();
                        return null;
                    }
                });
            }catch (Exception e){
            }
        }
        void doTask() {
            System.out.println(Thread.currentThread().getName() + " start");
            Random random = new Random();
            int _int = random.nextInt(200);
            System.out.println(Thread.currentThread().getName() + " sleep " + _int + "millis");
            try {
                Thread.sleep(_int);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println(Thread.currentThread().getName() + " end");
            doneSignal.countDown();
        }
    }

六、執行測試類：

Thread-48 start

Thread-48 sleep 99millis

Thread-48 end

Thread-49 start

Thread-49 sleep 118millis

Thread-49 end

Thread-52 start

Thread-52 sleep 141millis

Thread-52 end

Thread-50 start

Thread-50 sleep 28millis

Thread-50 end

Thread-51 start

Thread-51 sleep 145millis

Thread-51 end

不管怎麼樣，這是redis官方推薦的一種方案，可靠性比較高。

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