blocks|key|3246703|text|使用Thread.currentThread()|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3246704|private+class+MyTask+implements+Runnable+{
++++public+void+run()+{
++++++++long+threadId+=+Thread.currentThread().getId();
++++++++logger.debug("Thread+#+"+%2B+threadId+%2B+"+is+doing+this+task");
++++}
}|code-block|syntax|javascript|3246705|entityMap^0|2|M|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

Using <code>Thread.currentThread()</code>:

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

blocks|key|3032796|text|如果您的类继承自Thread，则可以使用getName和setName方法来命名每个线程。否则，您可以只向MyTask添加一个name字段，并在构造函数中对其进行初始化。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3032797|entityMap|0|LINK|mutability|MUTABLE|url|http://download.oracle.com/docs/cd/E17476_01/javase/1.4.2/docs/api/java/lang/Thread.html^0|K|7|S|7|1H|6|1R|4|8|6|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]|$9|U|A|V|B|C]]|D|@$9|W|A|X|1|Y]]|E|$]]|$1|F|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

If your class inherits from <a href="http://download.oracle.com/docs/cd/E17476_01/javase/1.4.2/docs/api/java/lang/Thread.html" rel="nofollow noreferrer">Thread</a>, you can use methods <code>getName</code> and <code>setName</code> to name each thread. Otherwise you could just add a <code>name</code> field to <code>MyTask</code>, and initialize it in your constructor.

blocks|key|304978|text|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，为什么还要这样做呢？我认为您在某处缺少记录日志消息的线程I的配置。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|304979|entityMap|0|LINK|mutability|MUTABLE|url|http://download.oracle.com/docs/cd/E17409_01/javase/6/docs/api/java/util/logging/LogRecord.html^0|1A|9|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

You can use Thread.getCurrentThread.getId(), but why would you want to do that when <a href="http://download.oracle.com/docs/cd/E17409_01/javase/6/docs/api/java/util/logging/LogRecord.html" rel="noreferrer">LogRecord</a> 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.

blocks|key|3032821|text|被接受的答案回答了关于获取线程id的问题，但它不允许您执行"Thread+X+of+Y“消息。线程ids在线程之间是唯一的，但不一定从0或1开始。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3032822|下面是一个与问题匹配的示例：|3032823|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%2B%2B)+{
++++++exec.execute(new+Runnable()+{
++++++++public+void+run()+{
++++++++++long+threadId+=+Thread.currentThread().getId();
++++++++++System.out.println("I+am+thread+"+%2B+threadId+%2B+"+of+"+%2B+numThreads);
++++++++}
++++++});
++++}

++++exec.shutdown();
++}
}|code-block|syntax|javascript|3032824|和输出：|3032825|burhan@orion:/dev/shm$+javac+ThreadIdTest.java+&&+java+ThreadIdTest
I+am+thread+8+of+5
I+am+thread+9+of+5
I+am+thread+10+of+5
I+am+thread+8+of+5
I+am+thread+9+of+5
I+am+thread+11+of+5
I+am+thread+8+of+5
I+am+thread+9+of+5
I+am+thread+10+of+5
I+am+thread+12+of+5|3032826|使用模算法的一个轻微调整将允许您正确地做“线程X+of+Y”：|3032827|//+modulo+gives+zero-based+results+hence+the+%2B1
long+threadId+=+Thread.currentThread().getId()%25numThreads+%2B1;|3032828|新结果：|3032829|burhan@orion:/dev/shm$+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+|3032830|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|F|7|14|8|@]|9|@]|A|$G|H]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

The accepted answer answers the question about getting a thread 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.

Here is an example matching the question:

<pre><code>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&lt;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();
 }
}
</code></pre>

and the output:

<pre><code>burhan@orion:/dev/shm$ javac ThreadIdTest.java &amp;&amp; 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
</code></pre>

A slight tweak using modulo arithmetic will allow you to do "thread X of Y" correctly:

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

New results:

<pre><code>burhan@orion:/dev/shm$ javac ThreadIdTest.java &amp;&amp; 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 
</code></pre>

blocks|key|3032842|text|如果您使用日志记录，那么线程名称将会很有帮助。线程工厂可以帮助实现这一点：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3032843|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+#+"+%2B+counter%2B%2B);
++++}
}|code-block|syntax|javascript|3032844|输出：|3032845|[+++My+thread+#+0]+Main+++++++++INFO++A+pool+thread+is+doing+this+task|3032846|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

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

<pre><code>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++);
 }
}
</code></pre>

Output:

<pre><code>[ My thread # 0] Main INFO A pool thread is doing this task
</code></pre>

blocks|key|302928|text|获取当前线程的方式有：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|302929|Thread+t+=+Thread.currentThread();|code-block|syntax|javascript|302930|在获得Thread类对象(t)之后，您可以使用Thread类方法获取所需的信息。|302931|线程ID获取：|302932|long+tId+=+t.getId();+//+e.g.+14291|302933|线程名称gettting：|302934|String+tName+=+t.getName();+//+e.g.+"pool-29-thread-7"|302935|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|V|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|W|8|@]|9|@]|A|$E|F]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

There is the way of current thread getting:

<pre><code>Thread t = Thread.currentThread();
</code></pre>

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

Thread ID gettting:

<pre><code>long tId = t.getId(); // e.g. 14291
</code></pre>

Thread name gettting: 

<pre><code>String tName = t.getName(); // e.g. "pool-29-thread-7"
</code></pre>

I have a fixed thread pool that I submit tasks to (limited to 5 threads). How can I find out which one of those 5 threads executes my task (something like "thread #3 of 5 is doing this task")?

<pre><code>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?
 }
}
</code></pre>

How to get thread id from a thread pool?

我有一个提交任务的固定线程池(仅限于5线程)。我如何才能找出这些5线程中的哪一个执行我的任务(类似于“5的线程#3正在执行这个任务”)？ExecutorService taskExecutor = Executors.newFixedThreadPool(5);//in infinite loop:taskExecut...

问如何从线程池中获取线程id？
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