SpringBoot Redis分布式锁的正确实现方式(4)

SpringBoot

把分布式锁接口定义出来，所谓面向接口和对象编程，代码如有神。顺带用英文显摆下什么叫做专业。

/**
 * 分布式锁
 */
public interface Lock {
    /**
     * Tries to acquire the lock with defined <code>leaseTime</code>.
     * Waits up to defined <code>waitTime</code> if necessary until the lock became available.
     * <p>* Lock will be released automatically after defined <code>leaseTime</code> interval.
     *
     * @param waitTime  the maximum time to acquire the lock
     * @param leaseTime lease time
     * @param unit      time unit
     * @return <code>true</code> if lock is successfully acquired,
     * otherwise <code>false</code> if lock is already set.
     * @throws InterruptedException - if the thread is interrupted
     */
    boolean tryLock(long waitTime, long leaseTime, TimeUnit unit) throws InterruptedException;
    /**
     * Acquires the lock with defined <code>leaseTime</code>.
     * Waits if necessary until lock became available.
     * <p>* Lock will be released automatically after defined <code>leaseTime</code> interval.
     *
     * @param leaseTime the maximum time to hold the lock after it's acquisition,
     *                  if it hasn't already been released by invoking <code>unlock</code>.
     *                  If leaseTime is -1, hold the lock until explicitly unlocked.
     * @param unit      the time unit
     */
    void lock(long leaseTime, TimeUnit unit);
    /**
     * Releases the lock.
     *
     * <p><b>Implementation Considerations</b>
     *
     * <p>A {@code Lock} implementation will usually impose
     * restrictions on which thread can release a lock (typically only the
     * holder of the lock can release it) and may throw
     * an (unchecked) exception if the restriction is violated.
     * Any restrictions and the exception
     * type must be documented by that {@code Lock} implementation.
     */
    void unlock();
}

青铜分布式锁实战

DistributedLock 实现 Lock 接口，构造方法实现 resourceName 和 StringRedisTemplate 的属性设置。

客户端唯一标识使用uuid:threadId 组成。

DistributedLock

public class DistributedLock implements Lock {
    /**
     * 标识 id
     */
    private final String id = UUID.randomUUID().toString();
    /**
     * 资源名称
     */
    private final String resourceName;
    private final List<String> keys = new ArrayList<>(1);
    /**
     * redis 客户端
     */
    private final StringRedisTemplate redisTemplate;
    public DistributedLock(String resourceName, StringRedisTemplate redisTemplate) {
        this.resourceName = resourceName;
        this.redisTemplate = redisTemplate;
        keys.add(resourceName);
    }
    private String getRequestId(long threadId) {
        return id + ":" + threadId;
    }
}