JDK 對線程組類注釋：

A thread group represents a set of threads. In addition, a thread group can also include other thread groups. The thread groups form a tree in which every thread group except the initial thread group has a parent.
A thread is allowed to access information about its own thread group, but not to access information about its thread group's parent thread group or any other thread groups.

可以把線程歸屬到某一個線程組中，線程組中可以有線程對象，也可以有線程組，組中還可以有線程，這樣的組織結構有點類似于樹的形式，如圖所示.

線程組的作用是：可以批量管理線程或線程組對象，有效地對線程或線程組對象進行組織

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１．線程組示例：

展示線程組結構代碼實例如下：

/*** 類功能描述：** @author WangXueXing create at 18-12-27 下午3:25* @version 1.0.0*/ public class ThreadGroupTest implements Runnable {@Overridepublic void run() {try {while (!Thread.currentThread().isInterrupted()) {Thread currentThread = Thread.currentThread();System.out.println("current thread:" + currentThread.getName()+" thread group:"+currentThread.getThreadGroup().getName()+" parent thread group:"+currentThread.getThreadGroup().getParent().getName());Thread.sleep(3000);}} catch (InterruptedException e) {e.printStackTrace();}}public static void main(String[] args) {ThreadGroup rootThreadGroup = new ThreadGroup("root線程組1");Thread t0 = new Thread(rootThreadGroup, new ThreadGroupTest(), "Thread 0");t0.start();ThreadGroup tg = new ThreadGroup(rootThreadGroup,"線程組1");ThreadGroup tg2 = new ThreadGroup(rootThreadGroup,"線程組2");Thread t1 = new Thread(tg, new ThreadGroupTest(), "Thread 1");Thread t2 = new Thread(tg, new ThreadGroupTest(), "Thread 2");t1.start();t2.start();Thread t3 = new Thread(tg2, new ThreadGroupTest(), "Thread 3");Thread t4 = new Thread(tg2, new ThreadGroupTest(), "Thread 4");t3.start();t4.start();} }

　　打印結果如下：

current thread:Thread 0 thread group:root線程組1 parent thread group:main current thread:Thread 2 thread group:線程組1 parent thread group:root線程組1 current thread:Thread 1 thread group:線程組1 parent thread group:root線程組1 current thread:Thread 3 thread group:線程組2 parent thread group:root線程組1 current thread:Thread 4 thread group:線程組2 parent thread group:root線程組1 current thread:Thread 1 thread group:線程組1 parent thread group:root線程組1 current thread:Thread 0 thread group:root線程組1 parent thread group:main current thread:Thread 2 thread group:線程組1 parent thread group:root線程組1 current thread:Thread 3 thread group:線程組2 parent thread group:root線程組1 ......

　　

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２．線程組項目中應用（線程組內的線程異常統一管理）：

最近有個需求，生成復雜報表－從很多表數據中分析統計到一個報表。

實現思路：

多個線程分別到不同表中查數據并統計分析，任何一個線程失敗整體報表生成失敗，記錄日志并立即中斷其他線程。全部線程成功，報表生成成功。

廢話少說以下利用Java線程組結合CountDownLatch實現代碼如下：

/*** 多線程獲取報表數據* @param reportId 報表ID* @return*/ def getReportData(reportId: Long, supplierDetailMap: ConcurrentHashMap[Integer, Supplier]):ConcurrentHashMap[Integer, AnyRef] = {val dataMap = new ConcurrentHashMap[Integer, AnyRef]()//多線程同步器val conutDownLatch = new CountDownLatch(3)//實例化線程組val genThreadGroup = new GenThreadGroup(request.reportInfo.reportType.name, reportId)//獲取當月已開返利new Thread(genThreadGroup, new Runnable {override def run(): Unit = {dataMap.put(OPENED_REBATE_CODE, SupplierAccountDetailQuerySql.getTaxDiscountByMonth(request))conutDownLatch.countDown()}}, "獲取當月已開返利").start()//獲取當月累計解押款new Thread(genThreadGroup, new Runnable {override def run(): Unit = {dataMap.put(DEPOSIT_BY_MONTH, SupplierAccountDetailQuerySql.getDepositAmountByMonth(request))conutDownLatch.countDown()}}, "獲取當月累計解押款").start()//結算單的含稅金額new Thread(genThreadGroup, new Runnable {override def run(): Unit = {dataMap.put(ACCOUNT_PAYABLE_AMOUNT, SupplierAccountDetailQuerySql.getAccountPayableAmount(request))conutDownLatch.countDown()}}, "獲取結算單的含稅金額").start()//所有線程都執行完成conutDownLatch.await()dataMap }

　　

統一捕獲異常的線程組定義如下： /*** 定義報表生成線程組** @author BarryWang create at 2018/5/21 11:04* @version 0.0.1*/ class GenThreadGroup(groupName: String, reportId: Long) extends ThreadGroup(groupName){val logger: Logger = LoggerFactory.getLogger(classOf[GenThreadGroup])/*** 定義線程組中任意一個線程異常處理* @param thread 當前線程* @param exception 異常*/override def uncaughtException(thread: Thread, exception: Throwable): Unit = {logger.error(s"報表(ID：${reportId})生成異常, 線程組：${groupName}; 線程：${thread.getName} 失敗", exception)thread.getThreadGroup.interrupt()} }

　　

轉載于:https://www.cnblogs.com/barrywxx/p/9976417.html

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