java 给线程池改名字的作用

秒速五厘米 2022-06-13 11:55 218阅读 0赞

近期weblogic会有很多线程，有时候能达到250个，其中有一类很有30-40个，就是如下所示，初一看多线程池，有很多个线程池，然后是生产者消费者模式。现在面临的问题是，如何定位是哪些功能？从目前情况来看无法定位，解决方法是把线程池的名字修改了，借此找到功能。  
"pool-21-thread-2" prio=10 tid=0x00007f41c00f9800 nid=0xc23d waiting on condition \[0x00007f42cb8f7000\]  
   java.lang.Thread.State: WAITING (parking)  
at sun.misc.Unsafe.park(Native Method)  
\- parking to wait for  <0x0000000738beac18> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)  
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)  
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2043)  
at java.util.concurrent.ArrayBlockingQueue.take(ArrayBlockingQueue.java:374)  
at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1068)  
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)  
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)  
at java.lang.Thread.run(Thread.java:745)  
  
"pool-21-thread-1" prio=10 tid=0x00007f41d4051800 nid=0xc22b waiting on condition \[0x00007f42cb7f6000\]  
   java.lang.Thread.State: WAITING (parking)  
at sun.misc.Unsafe.park(Native Method)  
\- parking to wait for  <0x0000000738beac18> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)  
at java.util.concurrent.locks.LockSupport.park(LockSupport.java:186)  
at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2043)  
at java.util.concurrent.ArrayBlockingQueue.take(ArrayBlockingQueue.java:374)  
at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1068)  
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)  
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)

at java.lang.Thread.run(Thread.java:745)

import java.util.concurrent.ArrayBlockingQueue;
    import java.util.concurrent.ThreadPoolExecutor;
    import java.util.concurrent.TimeUnit;
    
    public class ThreadPoolExecutorTEST {
        //池中所保存的线程数，包括空闲线程。
        final static int corePoolSize = 50;
        //池中允许的最大线程数。
        final static int maximumPoolSize = 100;
        //当线程数大于核心线程时，此为终止前多余的空闲线程等待新任务的最长时间
        final static long keepAliveTime = 300;
        //执行前用于保持任务的队列5，即任务缓存队列
        final static ArrayBlockingQueue<Runnable> workQueue =new ArrayBlockingQueue<Runnable>(50);
        public static void main(String[] args) {
            //构建一个线程池，正常线程数量为50，最大线程数据为100，等待时间300
            ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                    corePoolSize, maximumPoolSize, keepAliveTime, TimeUnit.MINUTES, workQueue);
            //线程池去执行50个任务
            for (int i = 0; i < 50; i++) {
                MyRunnable myRunnable = new MyRunnable(i);
                threadPoolExecutor.execute(myRunnable);
                System.out.println("线程池中现在的线程数目是："+threadPoolExecutor.getPoolSize()+",  队列中正在等待执行的任务数量为："+
                        threadPoolExecutor.getQueue().size());
            }
            //关掉线程池
            threadPoolExecutor.shutdown();
        }
    }
    
    public class MyRunnable implements Runnable {
        // 正在执行的任务数
        private int num;
        public MyRunnable(int num) {
            this.num = num;
        }
        public void run() {
            System.out.println("正在执行的MyRunnable " + num);
            try {
                Thread.currentThread().setName( "我的测试-"+num);
                Thread.currentThread().sleep(40000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            System.out.println("MyRunnable " + num + "执行完毕");
        }
    }

使用jstack的结果变为：

"我的测试-1" prio=6 tid=0x000000000c700800 nid=0x1bb4 waiting on condition \[0x000000001060e000\]  
   java.lang.Thread.State: TIMED\_WAITING (sleeping)  
at java.lang.Thread.sleep(Native Method)  
at MyRunnable.run(MyRunnable.java:17)  
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)  
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)  
at java.lang.Thread.run(Thread.java:745)  
  
"我的测试-2" prio=6 tid=0x000000000c6ff800 nid=0x1fc0 waiting on condition \[0x000000000fcce000\]  
   java.lang.Thread.State: TIMED\_WAITING (sleeping)  
at java.lang.Thread.sleep(Native Method)  
at MyRunnable.run(MyRunnable.java:17)  
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)  
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)  
at java.lang.Thread.run(Thread.java:745)