java try后没有catch,只有finnally
Posted fengyanqing
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今天看jdk1.6源码 ThreadPoolExecutor中Worker的runTask方法
catch(RunTimeException ex) 中 tthrow ex,会把ex抛到上层,上层try没有catch异常,该异常还会往上层抛,
try后直接跟finnally,finnally中runLock.unlock(),会释放锁;
总结:try....finnally 的用法主要是为了释放资源,不进行异常捕获,将异常交由上层调用者处理;
private void runTask(Runnable task) { final ReentrantLock runLock = this.runLock; runLock.lock(); try { /* * If pool is stopping ensure thread is interrupted; * if not, ensure thread is not interrupted. This requires * a double-check of state in case the interrupt was * cleared concurrently with a shutdownNow -- if so, * the interrupt is re-enabled. */ if ((runState >= STOP || (Thread.interrupted() && runState >= STOP)) && hasRun) thread.interrupt(); /* * Track execution state to ensure that afterExecute * is called only if task completed or threw * exception. Otherwise, the caught runtime exception * will have been thrown by afterExecute itself, in * which case we don‘t want to call it again. */ boolean ran = false; beforeExecute(thread, task); try { task.run(); ran = true; afterExecute(task, null); ++completedTasks; } catch (RuntimeException ex) { if (!ran) afterExecute(task, ex); throw ex; } } finally { runLock.unlock(); } }
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