java - 如何在另一个线程中启动事务？

Question

Spring 4。

我正在努力通过 ScheduledThreadPoolExecutor 实现可更新缓存。目前看起来如下:

public class MyService {

    @Setter
    private MyDao myDao;
    //Immutable
    private volatile Cache cache;

    //Static factory method
    public static MyService create(){
        MyService retVal = new MyService();
        cache = Cache.emptyCache();
        updateCache();
    }

    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public int get(){
         //Retrieving from cache
         return cache.getNext();
    }

    private void updateCache() {
        try{
            ScheduledExecutorService ses = Executors.newScheduledThreadPool(1);
            //The runnable should be in a transaction.
            Runnable updateCache;
            //the runnable queries the MyDao,
            //which in turn currently implemented as a DB-dao
            //The cache is assigned after computation
            ses.scheduleWithFixedDelay(updateCache, 0, 60, TimeUnit.SECONDS);
        } catch (Throwable t){ }
    }
}

我的问题是如何在事务中运行可运行作业？

只要事务是线程绑定(bind)的，将 updateCache() 注释为 @Transactional 将不起作用。

Answer 1

不要这样安排，使用 scheduling support Spring 。

public class MyService {

    @Setter
    private MyDao myDao;
    //Immutable
    private volatile Cache cache;

    //Static factory method
    public static MyService create(){
        MyService retVal = new MyService();
        cache = Cache.emptyCache();
        updateCache();
    }

    @Transactional(propagation = Propagation.REQUIRES_NEW)
    public int get(){
         //Retrieving from cache
         return cache.getNext();
    }

    @Transactional
    @Scheduled(fixedDelay=60000)
    public void updateCache() {
            //the runnable queries the MyDao,
            //which in turn currently implemented as a DB-dao
            //The cache is assigned after computation
    }
}

然后添加 @EnableScheduling或<task:annotation-driven /> 。另请参阅前面提到的链接以获取更多配置选项。