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我们。