Java 如何从线程池中获取线程ID？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/3294293/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to get thread id from a thread pool?
提问by serg
I have a fixed thread pool that I submit tasks to (limited to 5threads). How can I find out which one of those 5threads executes my task (something like "thread #3 of 5is doing this task")?
我有一个固定的线程池，我向它提交任务（限制为5 个线程）。如何找出这5 个线程中的哪一个执行我的任务（类似于“线程 #3 of 5正在执行此任务”）？
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?
}
}
采纳答案by skaffman
Using Thread.currentThread():
使用Thread.currentThread()：
private class MyTask implements Runnable {
public void run() {
long threadId = Thread.currentThread().getId();
logger.debug("Thread # " + threadId + " is doing this task");
}
}
回答by Justin Ethier
回答by Vineet Reynolds
You can use Thread.getCurrentThread.getId(), but why would you want to do that when LogRecordobjects 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.
您可以使用 Thread.getCurrentThread.getId()，但是当记录器管理的LogRecord对象已经具有线程 ID时，您为什么要这样做。我认为您在某处缺少记录日志消息的线程 ID 的配置。
回答by Burhan Ali
The accepted answer answers the question about getting athread id, but it doesn't let you do "Thread X of Y" messages. Thread ids are unique across threads but don't necessarily start from 0 or 1.
接受的答案回答了关于获取问题一个线程ID，但它不会让你的邮件“Y的主题X”。线程 ID 跨线程是唯一的，但不一定从 0 或 1 开始。
Here is an example matching the question:
这是一个匹配问题的示例：
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();
}
}
and the output:
和输出：
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
A slight tweak using modulo arithmetic will allow you to do "thread X of Y" correctly:
使用模运算稍作调整将允许您正确执行“Y 的线程 X”：
// modulo gives zero-based results hence the +1
long threadId = Thread.currentThread().getId()%numThreads +1;
New results:
新结果：
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
回答by Vitaliy Polchuk
If you are using logging then thread names will be helpful. A thread factory helps with this:
如果您正在使用日志记录，则线程名称会有所帮助。线程工厂有助于解决此问题：
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:
输出：
[ My thread # 0] Main INFO A pool thread is doing this task
回答by Serg.Stankov
There is the way of current thread getting:
当前线程的获取方式有：
Thread t = Thread.currentThread();
After you have got Thread class object (t) you are able to get information you need using Thread class methods.
获得 Thread 类对象 (t) 后，您就可以使用 Thread 类方法获取所需的信息。
Thread ID gettting:
线程 ID 获取：
long tId = t.getId(); // e.g. 14291
Thread name gettting:
线程名称获取：
String tName = t.getName(); // e.g. "pool-29-thread-7"
