spring自定义事务同步器（二）：借助redisson实现自己的同步器

1. 借助redis的java客户端redisson实现自己的事物同步器

    @Override
    public void lockWithinCurrentTransaction(Object key) {
        TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronizationAdapter() {
            @Override
            public void afterCompletion(int status) {
                unLock(key);
            }
        });

        lock(key);
    }

    private void lock(Object key) {

        RLock rlock = redissonClient.getLock(key.toString());
        if (!rlock.isHeldByCurrentThread()) {
            rlock.lock();
        }

    }

    private void unLock(Object key) {

        RLock rlock = redissonClient.getLock(key.toString());
        if (rlock.isHeldByCurrentThread())
            rlock.unlock();

    }

2.源码分析

    private static final ThreadLocal<Set<TransactionSynchronization>> synchronizations =
            new NamedThreadLocal<Set<TransactionSynchronization>>("Transaction synchronizations");

    /**
     * Register a new transaction synchronization for the current thread.
     * Typically called by resource management code.
     * <p>Note that synchronizations can implement the
     * {@link org.springframework.core.Ordered} interface.
     * They will be executed in an order according to their order value (if any).
     * @param synchronization the synchronization object to register
     * @throws IllegalStateException if transaction synchronization is not active
     * @see org.springframework.core.Ordered
     */
    public static void registerSynchronization(TransactionSynchronization synchronization)
            throws IllegalStateException {

        Assert.notNull(synchronization, "TransactionSynchronization must not be null");
        if (!isSynchronizationActive()) {
            throw new IllegalStateException("Transaction synchronization is not active");
        }
        synchronizations.get().add(synchronization);
    }