同时创建动态线程数

Question

每次我都要创建一个可变数量的线程.我这样做是通过创建一个Threads数组并创建多个线程.

但是,我不明白如何启动这些n个线程表现得像多线程概念.我希望他们并行运行.

请指导在这个场所做什么.

Answer 1

但是,我不明白如何启动这些n个线程表现得像多线程概念.我希望他们并行运行.

你当然可以使用循环创建一个线程数组:

 Thread[] threads = new Thread[NUM_JOBS_TO_CREATE];
 for (int i = 0; i < threads.length; i++) {
     threads[i] = new Thread(new Runnable() {
         public void run() {
             // some code to run in parallel
             // this could also be another class that implements Runnable
         }
     });
     threads[i].start();
 }

这将导致线程在后台并行运行.然后,您可以稍后与他们一起等待他们全部完成,然后再继续.

// wait for the threads running in the background to finish
for (Thread thread : threads) {
    thread.join();
}

但是我不建议自己管理线程,而是建议使用内置的JavaExecutors.他们为您做的所有这些都更容易管理.此方法的一个好处是它将任务与运行它们的线程分开.例如,您可以启动10个线程来并行运行1000和1000个任务.

这是一些示例ExecutorService代码:

 // create a pool of threads, 10 max jobs will execute in parallel
 ExecutorService threadPool = Executors.newFixedThreadPool(10);
 // submit jobs to be executing by the pool
 for (int i = 0; i < NUM_JOBS_TO_CREATE; i++) {
    threadPool.submit(new Runnable() {
         public void run() {
             // some code to run in parallel
             // this could also be another class that implements Runnable
         }
     });
 }
 // once you've submitted your last job to the service it should be shut down
 threadPool.shutdown();
 // wait for the threads to finish if necessary
 threadPool.awaitTermination(Long.MAX_VALUE, TimeUnit.MILLISECONDS);

有关更多信息,请参阅线程执行程序上的Java教程.

Answer 2

基本伪代码：

create x threads, store them in an array or list;
for each thread in the list/array
   call start() on the thread object;