我们的项目用到了ThreadGroup 把thread放到了threadGroup中，名称统一起来了；
private static final ExecutorService EXECUTOR_SERVICE = new ThreadPoolExecutor(, ,
5L, TimeUnit.MINUTES,
new ArrayBlockingQueue<>(), new ThreadFactory() { private final ThreadGroup threadGroup = new ThreadGroup("fileTemplateMethodThreadGroup"); private final AtomicInteger threadNumber = new AtomicInteger(); @Override
public Thread newThread(Runnable r) {
return new Thread(threadGroup, r, "fileTemplateMethod-thread-pool-" + threadNumber.getAndIncrement());
}
}, (r, executor) -> {
if (!executor.isShutdown()) {
/* 丢弃队列最老的数据 */
if (executor.getQueue().poll() != null) {
Cat.logMetricForCount(CatConstant.METRIC_DISCARD_FILE_TASK_COUNT);
}
executor.execute(r);
}
});
ThreadGroup 可以把thread的名字统一起来。一起处理catch。
ThreadGroup是Java提供的一种对线程进行分组管理的手段，可以对所有线程以组为单位进行操作，如设置优先级、守护线程等。
线程组也有父子的概念，如下图：
线程组的创建
public class ThreadGroupCreator {
public static void main(String[] args) {
//获取当前线程的group
ThreadGroup currentGroup = Thread.currentThread().getThreadGroup();
//在当前线程执行流中新建一个Group1
ThreadGroup group1 = new ThreadGroup("Group1");
//Group1的父线程,就是main线程所在Group
System.out.println(group1.getParent() == currentGroup);
//定义Group2, 指定group1为其父线程
ThreadGroup group2 = new ThreadGroup(group1, "Group2");
System.out.println(group2.getParent() == group1);
}
} ThreadGroup是位于java.lang包下的一个类,用于统一的线程管理.一旦一个线程加入到一个线程组后,就不能更换线程所在的线程组
将当前线程加入到线程组中
public class ThreadGroupCreator {
public static void main(String[] args) {
//获取当前线程的group
ThreadGroup currentGroup = Thread.currentThread().getThreadGroup();
//在当前线程执行流中新建一个Group1
ThreadGroup group1 = new ThreadGroup("Group1");
//Group1的父线程,就是main线程所在Group
System.out.println(group1.getParent() == currentGroup);
//定义Group2, 指定group1为其父线程
ThreadGroup group2 = new ThreadGroup(group1, "Group2");
System.out.println(group2.getParent() == group1);
}
} 将ThreadGroup中活跃的线程引用复制到线程组
Thread[] threads = new Thread[num];
threadGroup.enumerate(threads);
for (Thread t : threads) {
System.out.println("线程名-" + t.getName());
}
测试源代码如下
public class MyThread implements Runnable {
@Override
public void run() {
try {
System.out.println(Thread.currentThread().getName() + " -> start");
TimeUnit.SECONDS.sleep();
//随机发生异常
if (ThreadLocalRandom.current().nextInt() > ) {
throw new RuntimeException(Thread.currentThread().getName() + "发生异常");
}
System.out.println(Thread.currentThread().getName() + " -> end");
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public class ThreadGroupTest {
public static void main(String[] args) {
int num = ;
ThreadGroup threadGroup = new ThreadGroup("test-group") {
@Override
public void uncaughtException(Thread t, Throwable e) {
System.out.println("ThreadGroup捕获到线程异常 - " + e.getMessage());
}
};
List<Thread> threadList = new ArrayList<>();
for (int i = ; i < num; i++) {
Thread thread = new Thread(threadGroup, new MyThread(), "threadname-" + i);
threadList.add(thread);
}
System.out.println("运行前线程组中活跃线程数 -> " + threadGroup.activeCount());
System.out.println("开始运行所有线程...");
for (Thread t : threadList) {
t.start();
}
//获取线程组中所有[活动]线程
Thread[] threads = new Thread[num];
threadGroup.enumerate(threads);
for (Thread t : threads) {
System.out.println("线程名-" + t.getName());
}
System.out.println("所有线程运行后,线程组中活跃线程数-" + threadGroup.activeCount());
//不断的查看线程组中活跃的线程数
Thread thread = new Thread(() -> {
int num1;
try {
while ((num1 = threadGroup.activeCount()) > ) {
System.out.println("当前线程组活跃线程数为 -> " + num1);
TimeUnit.SECONDS.sleep();
}
System.out.println("All Thread HAS FINISHED");
} catch (InterruptedException e) {
e.printStackTrace();
}
});
thread.start();
}
}运行结果如下
运行前线程组中活跃线程数 -> 0
开始运行所有线程...
threadname- -> start
threadname- -> start
threadname- -> start
threadname- -> start
threadname- -> start
threadname- -> start
threadname- -> start
threadname- -> start
threadname- -> start
线程名-threadname-
threadname- -> start
线程名-threadname-
线程名-threadname-
线程名-threadname-
线程名-threadname-
线程名-threadname-
线程名-threadname-
线程名-threadname-
线程名-threadname-
线程名-threadname-
所有线程运行后,线程组中活跃线程数-
当前线程组活跃线程数为 ->
当前线程组活跃线程数为 ->
当前线程组活跃线程数为 ->
当前线程组活跃线程数为 ->
当前线程组活跃线程数为 ->
当前线程组活跃线程数为 ->
当前线程组活跃线程数为 ->
当前线程组活跃线程数为 ->
当前线程组活跃线程数为 ->
当前线程组活跃线程数为 ->
threadname- -> end
threadname- -> end
ThreadGroup捕获到线程异常 - threadname-7发生异常
ThreadGroup捕获到线程异常 - threadname-2发生异常
threadname- -> end
ThreadGroup捕获到线程异常 - threadname-3发生异常
ThreadGroup捕获到线程异常 - threadname-9发生异常
ThreadGroup捕获到线程异常 - threadname-1发生异常
threadname- -> end
threadname- -> end
All Thread HAS FINISHED
---------------------
线程组的基本操作
注意：后添加进线程组的线程，其优先级不能大于线程组的优先级
public class ThreadGroupBasic {
public static void main(String[] args) throws InterruptedException {
ThreadGroup group = new ThreadGroup("group1");
Thread thread = new Thread(group, () -> {
while(true) {
try {
TimeUnit.SECONDS.sleep();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}, "thread");
thread.setDaemon(true);
thread.start();
TimeUnit.MILLISECONDS.sleep();
ThreadGroup mainGroup = Thread.currentThread().getThreadGroup();
//递归获取mainGroup中活跃线程的估计值
System.out.println("activeCount = " + mainGroup.activeCount());
//递归获mainGroup中的活跃子group
System.out.println("activeGroupCount = " + mainGroup.activeGroupCount());
//获取group的优先级, 默认为10
System.out.println("getMaxPriority = " + mainGroup.getMaxPriority());
//获取group的名字
System.out.println("getName = " + mainGroup.getName());
//获取group的父group, 如不存在则返回null
System.out.println("getParent = " + mainGroup.getParent());
//活跃线程信息全部输出到控制台
mainGroup.list();
System.out.println("----------------------------");
//判断当前group是不是给定group的父线程, 如果两者一样,也会返回true
System.out.println("parentOf = " + mainGroup.parentOf(group));
System.out.println("parentOf = " + mainGroup.parentOf(mainGroup));
}
} 线程组的Interrupt
public class ThreadGroupInterrupt {
public static void main(String[] args) throws InterruptedException {
ThreadGroup group = new ThreadGroup("TestGroup");
new Thread(group, () -> {
while(true) {
try {
TimeUnit.MILLISECONDS.sleep();
} catch (InterruptedException e) {
//received interrupt signal and clear quickly
System.out.println(Thread.currentThread().isInterrupted());
break;
}
}
System.out.println("t1 will exit");
}, "t1").start();
new Thread(group, () -> {
while(true) {
try {
TimeUnit.MILLISECONDS.sleep();
} catch (InterruptedException e) {
//received interrupt signal and clear quickly
System.out.println(Thread.currentThread().isInterrupted());
break;
}
}
System.out.println("t2 will exit");
}, "t2").start();
//make sure all threads start
TimeUnit.MILLISECONDS.sleep();
group.interrupt();
}
} 线程组的destroy
public class ThreadGroupDestroy {
public static void main(String[] args) {
ThreadGroup group = new ThreadGroup("TestGroup");
ThreadGroup mainGroup = Thread.currentThread().getThreadGroup();
//before destroy
System.out.println("group.isDestroyed=" + group.isDestroyed());
mainGroup.list();
group.destroy();
//after destroy
System.out.println("group.isDestroyed=" + group.isDestroyed());
mainGroup.list();
}
} 线程组设置守护线程组
线程组设置为守护线程组，并不会影响其线程是否为守护线程，仅仅表示当它内部没有active的线程的时候，会自动destroy
public class ThreadGroupDaemon {
public static void main(String[] args) throws InterruptedException {
ThreadGroup group1 = new ThreadGroup("group1");
new Thread(group1, () -> {
try {
TimeUnit.SECONDS.sleep();
} catch (InterruptedException e) {
e.printStackTrace();
}
}, "group1-thread1").start();
ThreadGroup group2 = new ThreadGroup("group2");
new Thread(group2, () -> {
try {
TimeUnit.SECONDS.sleep();
} catch (InterruptedException e) {
e.printStackTrace();
}
}, "group1-thread2").start();
group2.setDaemon(true);
TimeUnit.SECONDS.sleep();
System.out.println(group1.isDestroyed());
System.out.println(group2.isDestroyed());
}
}