스레드 풀에서 스레드 ID를 얻는 방법은 무엇입니까?

스레드 풀에서 스레드 ID를 얻는 방법은 무엇입니까?

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작업을 제출하는 고정 스레드 풀이 있습니다 ( 5 개 스레드로 제한됨 ). 이 5 개의 스레드 중 어느 것이 내 작업을 실행 하는지 어떻게 알 수 있습니까 ( " 5 번 스레드 # 3 / 5 가이 작업을 수행 중입니다")?

ExecutorService taskExecutor = Executors.newFixedThreadPool(5);

//in infinite loop:
taskExecutor.execute(new MyTask());
....

private class MyTask implements Runnable {
    public void run() {
        logger.debug("Thread # XXX is doing this task");//how to get thread id?
    }
}

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사용 Thread.currentThread():

private class MyTask implements Runnable {
    public void run() {
        long threadId = Thread.currentThread().getId();
        logger.debug("Thread # " + threadId + " is doing this task");
    }
}

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허용되는 답변 은 스레드 ID 를 얻는 방법 에 대한 질문에 답변 하지만 "Thread X of Y"메시지를 표시 할 수는 없습니다. 스레드 ID는 스레드에서 고유하지만 반드시 0 또는 1에서 시작하지 않아도됩니다.

다음은 질문과 일치하는 예입니다.

import java.util.concurrent.*;
class ThreadIdTest {

  public static void main(String[] args) {

    final int numThreads = 5;
    ExecutorService exec = Executors.newFixedThreadPool(numThreads);

    for (int i=0; i<10; i++) {
      exec.execute(new Runnable() {
        public void run() {
          long threadId = Thread.currentThread().getId();
          System.out.println("I am thread " + threadId + " of " + numThreads);
        }
      });
    }

    exec.shutdown();
  }
}

그리고 출력 :

burhan@orion:/dev/shm$ javac ThreadIdTest.java && java ThreadIdTest
I am thread 8 of 5
I am thread 9 of 5
I am thread 10 of 5
I am thread 8 of 5
I am thread 9 of 5
I am thread 11 of 5
I am thread 8 of 5
I am thread 9 of 5
I am thread 10 of 5
I am thread 12 of 5

모듈로 산술을 사용하여 약간 조정하면 "스레드 X의 Y"를 올바르게 수행 할 수 있습니다.

// modulo gives zero-based results hence the +1
long threadId = Thread.currentThread().getId()%numThreads +1;

새로운 결과 :

burhan@orion:/dev/shm$ javac ThreadIdTest.java && java ThreadIdTest  
I am thread 2 of 5 
I am thread 3 of 5 
I am thread 3 of 5 
I am thread 3 of 5 
I am thread 5 of 5 
I am thread 1 of 5 
I am thread 4 of 5 
I am thread 1 of 5 
I am thread 2 of 5 
I am thread 3 of 5 

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You can use Thread.getCurrentThread.getId(), but why would you want to do that when LogRecord objects managed by the logger already have the thread Id. I think you are missing a configuration somewhere that logs the thread Ids for your log messages.

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If your class inherits from Thread, you can use methods getName and setName to name each thread. Otherwise you could just add a name field to MyTask, and initialize it in your constructor.

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If you are using logging then thread names will be helpful. A thread factory helps with this:

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadFactory;

public class Main {

    static Logger LOG = LoggerFactory.getLogger(Main.class);

    static class MyTask implements Runnable {
        public void run() {
            LOG.info("A pool thread is doing this task");
        }
    }

    public static void main(String[] args) {
        ExecutorService taskExecutor = Executors.newFixedThreadPool(5, new MyThreadFactory());
        taskExecutor.execute(new MyTask());
        taskExecutor.shutdown();
    }
}

class MyThreadFactory implements ThreadFactory {
    private int counter;
    public Thread newThread(Runnable r) {
        return new Thread(r, "My thread # " + counter++);
    }
}

Output:

[   My thread # 0] Main         INFO  A pool thread is doing this task

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There is the way of current thread getting:

Thread t = Thread.currentThread();

After you have got Thread class object (t) you are able to get information you need using Thread class methods.

Thread ID gettting:

long tId = t.getId();

Thread name gettting:

String tName = t.getName();

참고URL : https://stackoverflow.com/questions/3294293/how-to-get-thread-id-from-a-thread-pool