Spring中TransactionSynchronizationManager的使用详解

public abstract class TransactionSynchronizationManager {
	private static final Log logger = LogFactory.getLog(TransactionSynchronizationManager.class);
	private static final ThreadLocal<Map<Object, Object>> resources =
			new NamedThreadLocal<>("Transactional resources");
	private static final ThreadLocal<Set<TransactionSynchronization>> synchronizations =
			new NamedThreadLocal<>("Transaction synchronizations");
	private static final ThreadLocal<String> currentTransactionName =
			new NamedThreadLocal<>("Current transaction name");
	private static final ThreadLocal<Boolean> currentTransactionReadOnly =
			new NamedThreadLocal<>("Current transaction read-only status");
	private static final ThreadLocal<Integer> currentTransactionIsolationLevel =
			new NamedThreadLocal<>("Current transaction isolation level");
	private static final ThreadLocal<Boolean> actualTransactionActive =
			new NamedThreadLocal<>("Actual transaction active");
    // ...
}

    public void save(){
        // 保存用户
        saveUser();
        // 发送消息 异步执行
        executorService.execute(() -> sendMessage());
    }

    public void save(){
        // 保存用户
        saveUser();
        // 判断当前线程是否存在活跃状态的事务
        boolean actualTransactionActive = TransactionSynchronizationManager.isActualTransactionActive();
        // 不存在则事务都完成
        if (!actualTransactionActive){
            // 异步操作 发送消息
            executorService.execute(() -> sendMessage());
        }else{
            // 存在活跃事务, 则监听事务, afterCommit是指事务提交完再执行
            TransactionSynchronizationManager.registerSynchronization(new TransactionSynchronizationAdapter() {
                @Override
                public void afterCommit() {
                   // 异步操作 发送消息
                    executorService.execute(() -> sendMessage());
                }
            });
        }
}

public abstract class TransactionSynchronizationAdapter implements TransactionSynchronization, Ordered {
	@Override
	public int getOrder() {
		return Ordered.LOWEST_PRECEDENCE;
	}
    // 暂停此同步 应该从事务同步管理器中解绑资源
	@Override
	public void suspend() {
	}
    //  恢复此同步。 应该将资源重新绑定到 TransactionSynchronizationManager
	@Override
	public void resume() {
	}
    // 将基础会话刷新到数据存储
	@Override
	public void flush() {
	}
    // 在事务提交之前调用（在完成之前之前）顺序倒数第四
	@Override
	public void beforeCommit(boolean readOnly) {
	}
    // 在事务提交/回滚之前调用。顺序倒数第三
	@Override
	public void beforeCompletion() {
	}
    // 在事务提交后调用  顺序倒数第二
	@Override
	public void afterCommit() {
	}
    // 在事务提交/回滚后调用 可以进行资源清理 顺序倒数第一
	@Override
	public void afterCompletion(int status) {
	}
}