java獲取當前線程方法,java獲取當前線程信息

本文目錄一覽：

• 1、java獲得當前線程有兩種方法，第一種是Thread.currentThread();誰知道另外一種？
• 2、java獲取當前線程狀態。
• 3、java 如何獲得線程池中正在執行的線程數

java獲得當前線程有兩種方法，第一種是Thread.currentThread();誰知道另外一種？

另外一種是實現Runnable介面，implements Runnable

這種方法有兩個好處是

(1)適合多個相同程序代碼的線程去處理同一資源的情況，把虛擬CPU（線程）同程序的代碼，數據有效的分離，較好地體現了面向對象的設計思想。

(2)可以避免由於Java的單繼承特性帶來的局限。經常碰到這樣一種情況，即當要將已經繼承了某一個類的子類放入多線程中，由於一個類不能同時有兩個父類，所以不能用繼承Thread類的方式，那麼，這個類就只能採用實現Runnable介面的方式了。

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 如何獲得線程池中正在執行的線程數

java中線程池的監控可以檢測到正在執行的線程數。

通過線程池提供的參數進行監控。線程池裡有一些屬性在監控線程池的時候可以使用

taskCount：線程池需要執行的任務數量。

completedTaskCount：線程池在運行過程中已完成的任務數量。小於或等於taskCount。

largestPoolSize：線程池曾經創建過的最大線程數量。通過這個數據可以知道線程池是否滿過。如等於線程池的最大大小，則表示線程池曾經滿了。

getPoolSize:線程池的線程數量。如果線程池不銷毀的話，池裡的線程不會自動銷毀，所以這個大小隻增不+

getActiveCount：獲取活動的線程數。

通過擴展線程池進行監控。通過繼承線程池並重寫線程池的beforeExecute，afterExecute和terminated方法，我們可以在任務執行前，執行後和線程池關閉前干一些事情。如監控任務的平均執行時間，最大執行時間和最小執行時間等。這幾個方法在線程池裡是空方法。如：

protected

void

beforeExecute(Thread

t,

Runnable

r)

{

}