java线程，设置队列的大小实现队列阻塞
public class QueueThreads {
private static int nThreads = 4;//Runtime.getRuntime().availableProcessors() * 2 + 1;
private static BlockingQueue<Runnable> queue = new ArrayBlockingQueue<Runnable>(4);//队列值大小设置为4
private static ExecutorService executors = new ThreadPoolExecutor(nThreads, nThreads, 0L, TimeUnit.MILLISECONDS, queue, new ThreadFactory() {
private final String threadNamePrefix = "si_query_task_";
private final AtomicInteger count = new AtomicInteger(1);
@Override
public Thread newThread(Runnable r) {
Thread t = new Thread(Thread.currentThread().getThreadGroup(), r, threadNamePrefix + count.getAndIncrement());
//t.setDaemon(true);
return t;
}
});
public static void main(String[] args) {
for (int i = 0; i < 10; i++) {
try {
executors.execute(new Thread(new ThreadPoolTest(), "TestThread".concat("" + i)));
int threadSize = queue.size();
System.out.println("线程队列大小为-->" + threadSize);
} catch(RejectedExecutionException e){
System.out.println("阻塞异常");
}catch (Exception e) {
System.out.println("异常");
}
}
executors.shutdown();
}
public void run() {
synchronized (this) {
try {
System.out.println("线程名称：" + Thread.currentThread().getName());
Thread.sleep(3000); //休眠是为了让该线程不至于执行完毕后从线程池里释放
} catch (InterruptedException e) {
//e.printStackTrace();
}
}
}
}
本测试程序的队列设置为4，线程池的大小为4，循环开启10个任务执行结果：
分析：有8个任务执行成功了，线程处理完成立马会处理新的任务，但是出现了两个阻塞异常，原因是这两个任务来不及创建就被阻塞了，阻塞的结果就是丢弃。