java监控多个线程的实现
场景:需要启动多线程处理事情,而在所有事情做完之后,需要修改系统状态;那么如何判断所有线程(事情)都做完了呢?这就需要判断所有当前运行的线程状态了。
代码
private class TestThread implements Runnable {
private CountDownLatch threadsSignal;
public TestThread(CountDownLatch threadsSignal) {
this.threadsSignal = threadsSignal;
}
public void run() {
System.out.println(Thread.currentThread().getName() + "开始...");
// do shomething
System.out.println("开始了线程::::" + threadsSignal.getCount());
// 线程结束时计数器减1
threadsSignal.countDown();
System.out.println(Thread.currentThread().getName() + "结束. 还有"
+ threadsSignal.getCount() + " 个线程");
}
}
}
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
/** 测试监控类 */
public class WatchThread {
/** 测试函数 */
public void testThread() throws InterruptedException {
int threadNum = 10;
// 初始化countDown
CountDownLatch threadSignal = new CountDownLatch(threadNum);
// 创建固定长度的线程池
Executor executor = Executors.newFixedThreadPool(threadNum);
for (int i = 0; i < threadNum; i++) { // 开threadNum个线程
Runnable task = new TestThread(threadSignal);
// 执行
executor.execute(task);
}
threadSignal.await(); // 等待所有子线程执行完
// do work
System.out.println(Thread.currentThread().getName() + "+++++++结束.");
}
/** 测试函数 */
public static void main(String[] args) throws InterruptedException {
WatchThread test = new WatchThread();
test.testThread();
}
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
/** 测试监控类 */
public class WatchThread {
/** 测试函数 */
public void testThread() throws InterruptedException {
int threadNum = 10;
// 初始化countDown
CountDownLatch threadSignal = new CountDownLatch(threadNum);
// 创建固定长度的线程池
Executor executor = Executors.newFixedThreadPool(threadNum);
for (int i = 0; i < threadNum; i++) { // 开threadNum个线程
Runnable task = new TestThread(threadSignal);
// 执行
executor.execute(task);
}
threadSignal.await(); // 等待所有子线程执行完
// do work
System.out.println(Thread.currentThread().getName() + "+++++++结束.");
}
/** 测试函数 */
public static void main(String[] args) throws InterruptedException {
WatchThread test = new WatchThread();
test.testThread();
}
private class TestThread implements Runnable {
private CountDownLatch threadsSignal;
public TestThread(CountDownLatch threadsSignal) {
this.threadsSignal = threadsSignal;
}
public void run() {
System.out.println(Thread.currentThread().getName() + "开始...");
// do shomething
System.out.println("开始了线程::::" + threadsSignal.getCount());
// 线程结束时计数器减1
threadsSignal.countDown();
System.out.println(Thread.currentThread().getName() + "结束. 还有"
+ threadsSignal.getCount() + " 个线程");
}
}
}