Question

这样我生成线程，但在for循环之后如何检查所有线程是否存活进一步的过程取决于所有的线程
如果线程为dead，则进行进一步处理

for (int i = 0;i<List.size();i++) {
                if(List.get(i).trim().length() >0 ){

                    Thread thread = new Thread("Thread"+i){
                        public void run(){              
                            threading(List.get(i),ctx,userSesionObj);
                        }
                      };
                      thread.start();
                }
            }

这里threading是我的函数，它执行我传递的不同数据

Answer 1

您可以使用ExecutorService。事实上，我强烈推荐这一点。您可以指定不同的线程行为等。执行程序将为每个提交的线程返回一个Future对象，然后您可以遍历每个Future收集结果。以下是：

for (Future f : futures) {
   f.get(); // get a result here...
}

当所有Futures都返回数据时（即线程完成时），

将完成。 Executor API的工作级别高于join() / notify()等，使用起来更安全。

有很多功能可以在这里使用，我会推荐tutorials。

Answer 2

您可能希望join线程。参看http://docs.oracle.com/javase/tutorial/essential/concurrency/join.html。鉴于您可以暂停主线程，即。

Answer 3

使用ExecutorService

- Executors管理Thread个对象和Async任务井

- 这里不是直接运行线程的客户端，而是中间对象。

- 将此与submit()方法结合使用，该方法返回Future对象。

- Future是异步任务的结果。

- 您可以使用Future的get()方法，其具有阻止性质，或get()方法以及isDone()方法方法。

Answer 4

使用Thread类中的方法 isAlive 。

来自文档：

测试此线程是否存活。如果一个线程已经启动并且还没有死亡，那么它就是活着的。

Answer 5

正如彼得所说，这应该做......

int count = selectedCategoryList.size();
List<Thread> threads = new ArrayList<Thread>();
for (int i = 0; i < count; i++) {
  if(selectedCategoryList.get(i).trim().length() >0 ){
    final Long CategoryID = Long.parseLong(selectedCategoryList.get(i));
    Thread thread = new Thread("ReplaceMedicationThread"+i){
                          public void run(){              
                            threadingForReplacingMedication(CategoryID,ctx,userSesionObj);
                          }
                    };
    threads.add(thread):
   }
}

//start them in a loop
//join them in a loop
//move on....

Answer 6

在继续处理之前等待一些线程完成的简单方法是通过CompletionService。这就是你如何使用它：

// list of data that need to be processed before continuing execution
List<DataForProcessing> workList = // ...

// An instance of an Executor http://docs.oracle.com/javase/1.5.0/docs/api/java/util/concurrent/Executors.html
Executor exec = // ...

// asume that ResultData is a data structure returned from the processing each
// DataForProcessing instance. If processing does not return a value you could
// parameterise the completion service as CompletionService<Void>.
CompletionService<ResultData> service = new ExecutorCompletionService<ResultData>(executor);

// Submit the tasks for processing. Each task will be processed by the executor and
// its result will be wrapped in a Future and place in a BlockingQueue maintained by
// the CompletionService instance. Again, if your submitted task does not return
// a value you should parameterise your task as Callable<Void>.
for (DataForProcessing data: workList) {
  service.submit(new Callable<ResultData>() {
    public ResultData call() {
      // process the data here and return some result (optionally).
    }
  });
 }

// retrieve the results as the become available.
for (int i = 0; i < workLoad.size(); i++) {
  // Retrieve the next processed result. CompletionService returns each task in a
  // Future which provides you with the means to control the lifecycle of the task.
  // When a submitted task is processed by the executor, its Future is placed on a
  // BlockingQueue maintained by the CompletionService. Invoking take() will return
  // the next available result. If your tasks do not return a result you would still
  // need to call Future<Void> f = service.take() in order to wait for every task
  // to finish before proceeding.
  Future<ResultData> f = service.take();
  // If your task returns some result you may access it via the get() method on the
  // task's Future.
  ResultData result = f.get();
  // do some processing if needed
  process(result);
}

Answer 7

我刚刚使用简单的一个全局int参数完成了它。我喜欢这样：

do{
    Thread.sleep(800);
    System.out.println("threadCounter=="+threadCounter);
    }while(threadCounter != 0);

其中threadCounter定义全局int初始化zero

关于制作每个帖子我做threadCounter;

的+1

在我的函数threading中，我在threadCounter

的-1

这里Thread.sleep(800)因为没有运行do-while循环继续。

java多线程isalive与否

7 个答案: