打印Java程序的线程栈信息方式

打印Java程序的线程栈信息

jstack可以得知当前线程的运行情况

安装jstack等命令集，jstack是开发版本jdk的一部分，不是开发版的有可能找不到

yum install -y  java-1.8.0-openjdk-devel

查看要打印堆栈的java进程ID

jps -l

打印堆栈

sudo -u admin jstack pid  > jstack.txt

特别要注意的是jstack需要使用与进程一致的用户才能正确导出堆栈，否则会报错如下

Unable to open socket file: target process not responding or HotSpot VM not loaded

线程池异常堆栈的坑

import java.util.concurrent.*;
public class DivTask implements Runnable{
  int a,b;
  public DivTask(int a, int b) {
      this.a = a;
      this.b = b;
  }
  @Override
  public void run() {
      double re = a/b;
      System.out.println(re);
  }
  public static void main(String[] args) throws InterruptedException, ExecutionException {
//        ThreadPoolExecutor executor = new ThreadPoolExecutor(0, Integer.MAX_VALUE, 0L, TimeUnit.SECONDS
//                , new SynchronousQueue<>());
      TraceThreadPoolExecutor executor = new TraceThreadPoolExecutor(0, Integer.MAX_VALUE, 0L, TimeUnit.SECONDS
              , new SynchronousQueue<>());  //扩展TraceThreadPoolExecutor
      for (int i = 0; i < 5; i++) {
          // executor.submit(new DivTask(100,i));
          //改进方式一：
          //Future re = executor.submit(new DivTask(100, i));
          //re.get();
          //改进方式二：
          executor.execute(new DivTask(100,i));
      }
      //100.0
      //25.0
      //33.0
      //50.0
      //其中100/0的异常结果没打印
      //线程池很有可能"吃掉程序抛出的异常
      //改进方式一：
      //Exception in thread "main" java.util.concurrent.ExecutionException: java.lang.ArithmeticException: / by zero
      //	at java.util.concurrent.FutureTask.report(FutureTask.java:122)
      //	at java.util.concurrent.FutureTask.get(FutureTask.java:192)
      //。。。
      //改进方式二：
      //Exception in thread "pool-1-thread-1" java.lang.ArithmeticException: / by zero
      //	at com.Test.DivTask.run(DivTask.java:15)
      //	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
      //	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
      //	at java.lang.Thread.run(Thread.java:748)
      //100.0
      //33.0
      //25.0
      //50.0
      //扩展TraceThreadPoolExecutor
      //java.lang.Exception: Client stack trace
      //	at com.Test.TraceThreadPoolExecutor.clientTrace(TraceThreadPoolExecutor.java:20)
      //	at com.Test.TraceThreadPoolExecutor.execute(TraceThreadPoolExecutor.java:12)
      //	at com.Test.DivTask.main(DivTask.java:29)
      //Exception in thread "pool-1-thread-1" java.lang.ArithmeticException: / by zero
      //	at com.Test.DivTask.run(DivTask.java:15)
      //	at com.Test.TraceThreadPoolExecutor.lambda$wrap$0(TraceThreadPoolExecutor.java:25)
      //	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
      //	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
      //	at java.lang.Thread.run(Thread.java:748)
      //100.0
      //25.0
      //33.0
      //50.0
  }
}

import java.util.concurrent.*;
/**
* 扩展TraceThreadPoolExecutor，让它在调度任务前先保存一下提交任务线程的堆栈信息
*/
public class TraceThreadPoolExecutor extends ThreadPoolExecutor {
  public TraceThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) {
      super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
  }
  @Override
  public void execute(Runnable task) {
      super.execute(wrap(task,clientTrace(),Thread.currentThread().getName()));
  }
  @Override
  public Future<?> submit(Runnable task) {
      return super.submit(wrap(task,clientTrace(),Thread.currentThread().getName()));
  }
  private Exception clientTrace(){
      return new Exception("Client stack trace");
  }
  private Runnable wrap(final Runnable task,final Exception clientTrace,String clientThreadName){
      return () -> {
          try {
              task.run();
          } catch (Exception e) {
              clientTrace.printStackTrace();
              throw e;
          }
      };
  }
}

以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程宝库。

Java Runnable线程传参,让run访问参数。做Android开发，可能经常要用到Runnable线程，有时候可能需要传参数进去，然后在run函数中取出参数使用。解决办法：自定义一个接口，继承Runnable，新增一个传参方法