实现
/**
* 1.创建一个可缓存线程池,如果线程池长度超过处理需要,可灵活回收空闲线程,若无可回收,则新建线程
*/
public static void cachedThreadPool() {
ExecutorService cachedThreadPool = Executors.newCachedThreadPool();
for (int i = 0; i < 10; i++) {
final int index = i;
try {
Thread.sleep(1 * 1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
cachedThreadPool.execute(new Runnable() {
@Override
public void run() {
System.out.println(index + "--" + Thread.currentThread().getId());
}
});
}
}
/**
* 2.创建一个定长线程池,可控制线程最大并发数,超出的线程会在队列中等待
*/
public static void newFixedThreadPool() {
ExecutorService fixedThreadPool = Executors.newFixedThreadPool(5);
for (int i = 0; i < 10; i++) {
final int index = i;
fixedThreadPool.execute(new Runnable() {
@Override
public void run() {
try {
System.out.println(index + "-----" + Thread.currentThread().getId());
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
}
//fixedThreadPool.shutdown();
}
/**
* 3.创建一个定长线程池,支持定时及周期性任务执行
*/
public static void newScheduledThreadPool() {
ScheduledExecutorService scheduledThreadPool = Executors.newScheduledThreadPool(5);
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.HOUR_OF_DAY, 10); // 时
calendar.set(Calendar.MINUTE, 53);// 分
calendar.set(Calendar.SECOND, 00); // 秒
//计算现在时间和计划任务执行时间差多久,单位毫秒
Long date = calendar.getTime().getTime() - System.currentTimeMillis();
// //延迟3秒执行
scheduledThreadPool.schedule(new Runnable() {
@Override
public void run() {
System.out.println("delay 3 seconds--" + new Date().toLocaleString());
}
}, 3, TimeUnit.SECONDS);
//延迟5秒执行,然后每隔2秒执行一次
scheduledThreadPool.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
System.out.println("延迟5秒执行,然后每隔2秒执行一次--" + new Date().toLocaleString());
}
}, 5, 2, TimeUnit.SECONDS);
//定时在某一时刻执行任务,然后间隔执行,如果时间过了会立马执行
scheduledThreadPool.scheduleAtFixedRate(new Runnable() {
@Override
public void run() {
System.out.println("定时在某一时刻执行任务,然后间隔执行--" + new Date().toLocaleString());
}
}, date / 1000, 2, TimeUnit.SECONDS);
}
/**
*4. 创建一个单线程化的线程池,它只会用唯一的工作线程来执行任务,
* 保证所有任务按照指定顺序(FIFO, LIFO, 优先级)执行
*/
public static void newSingleThreadExecutor() {
ExecutorService singleThreadExecutor = Executors.newSingleThreadExecutor();
for (int i = 0; i < 10; i++) {
final int index = i;
singleThreadExecutor.execute(new Runnable() {
@Override
public void run() {
try {
System.out.println("单线程执行任务。。。");
Thread.sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
}
}