java查詢所有線程狀態,linux查看java線程數

本文目錄一覽：

• 1、java獲取當前線程狀態。
• 2、java多線程有哪些狀態？
• 3、如何查看一個java進程有多少個線程在工作？

java獲取當前線程狀態。

java線程的狀態有下面幾種狀態：

/**

* Thread state for a thread which has not yet started.

*/

NEW,

/**

* Thread state for a runnable thread. A thread in the runnable

* state is executing in the Java virtual machine but it may

* be waiting for other resources from the operating system

* such as processor.

*/

RUNNABLE,

/**

* Thread state for a thread blocked waiting for a monitor lock.

* A thread in the blocked state is waiting for a monitor lock

* to enter a synchronized block/method or

* reenter a synchronized block/method after calling

* {@link Object#wait() Object.wait}.

*/

BLOCKED,

/**

* Thread state for a waiting thread.

* A thread is in the waiting state due to calling one of the

* following methods:

* ul

* li{@link Object#wait() Object.wait} with no timeout/li

* li{@link #join() Thread.join} with no timeout/li

* li{@link LockSupport#park() LockSupport.park}/li

* /ul

*

* pA thread in the waiting state is waiting for another thread to

* perform a particular action.

*

* For example, a thread that has called ttObject.wait()/tt

* on an object is waiting for another thread to call

* ttObject.notify()/tt or ttObject.notifyAll()/tt on

* that object. A thread that has called ttThread.join()/tt

* is waiting for a specified thread to terminate.

*/

WAITING,

/**

* Thread state for a waiting thread with a specified waiting time.

* A thread is in the timed waiting state due to calling one of

* the following methods with a specified positive waiting time:

* ul

* li{@link #sleep Thread.sleep}/li

* li{@link Object#wait(long) Object.wait} with timeout/li

* li{@link #join(long) Thread.join} with timeout/li

* li{@link LockSupport#parkNanos LockSupport.parkNanos}/li

* li{@link LockSupport#parkUntil LockSupport.parkUntil}/li

* /ul

*/

TIMED_WAITING,

/**

* Thread state for a terminated thread.

* The thread has completed execution.

*/

TERMINATED;

java多線程有哪些狀態？

初始態：一個線程調用了new方法之後，並在調用start方法之前的所處狀態。

就緒：一旦線程調用了start 方法，線程就轉到Runnable 狀態。

阻塞/ NonRunnable：線程處於阻塞/NonRunnable狀態，這是由兩種可能性造成的：要麼是因掛起而暫停的，要麼是由於某些原因而阻塞的，例如包括等待IO請求的完成。

停止/退出：線程轉到退出狀態，這有兩種可能性，要麼是run方法執行結束，要麼是調用了stop方法。

如何查看一個java進程有多少個線程在工作？

理論上來說，如果你全用threadgroup來跑線程的話，有個叫enumerate的方法可以得到【該threadgroup下】所有active的(也就是你說的在工作的)線程以及子線程，但程序裡面不一定是把線程放threadgroup裡面的，有可能有人自己new一個出來run或者別的，所以不能完全依靠這個辦法。我目前想到的辦法，貌似得弄個全局的counter，開個守護線程，讓這個線程去數監控所有線程的狀態，依照線程是否Active去加減這個counter。

還有個懶點的，你看windows的taskmanager（假設你在win平台上的話），裡面有一個column叫做thread count的，我沒試過到底準不準，不過這個最省事了，右鍵點出來一看就知道了。