public class TestThreadPool {
//定长线程池，每当提交一个任务就创建一个线程，直到达到线程池的最大数量，这时线程数量不再变化，当线程发生错误结束时，线程池会补充一个新的线程
static ExecutorService fixedExecutor = Executors.newFixedThreadPool(3);
public static void main(String[] args) {
testFixedExecutor();
}
//测试定长线程池，线程池的容量为3，提交6个任务，根据打印结果可以看出先执行前3个任务，3个任务结束后再执行后面的任务
private static void testFixedExecutor() {
for (int i = 0; i < 6; i ) {
final int index = i;
fixedExecutor.execute(new Runnable() {
public void run() {
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() " index:" index);
}
});
}
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("4秒后...");
fixedExecutor.shutdown();
}
}
pool-1-thread-1 index:0 pool-1-thread-2 index:1 pool-1-thread-3 index:2 4秒后... pool-1-thread-3 index:5 pool-1-thread-1 index:3 pool-1-thread-2 index:4
public class TestThreadPool {
//可缓存的线程池，如果线程池的容量超过了任务数，自动回收空闲线程，任务增加时可以自动添加新线程，线程池的容量不限制
static ExecutorService cachedExecutor = Executors.newCachedThreadPool();
public static void main(String[] args) {
testCachedExecutor();
}
//测试可缓存线程池
private static void testCachedExecutor() {
for (int i = 0; i < 6; i ) {
final int index = i;
cachedExecutor.execute(new Runnable() {
public void run() {
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() " index:" index);
}
});
}
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("4秒后...");
cachedExecutor.shutdown();
}
}
pool-1-thread-1 index:0 pool-1-thread-6 index:5 pool-1-thread-5 index:4 pool-1-thread-4 index:3 pool-1-thread-3 index:2 pool-1-thread-2 index:1 4秒后...
public class TestThreadPool {
//定长线程池，可执行周期性的任务
static ScheduledExecutorService scheduledExecutor = Executors.newScheduledThreadPool(3);
public static void main(String[] args) {
testScheduledExecutor();
}
//测试定长、可周期执行的线程池
private static void testScheduledExecutor() {
for (int i = 0; i < 3; i ) {
final int index = i;
//scheduleWithFixedDelay 固定的延迟时间执行任务；scheduleAtFixedRate 固定的频率执行任务
scheduledExecutor.scheduleWithFixedDelay(new Runnable() {
public void run() {
System.out.println(Thread.currentThread().getName() " index:" index);
}
}, 0, 3, TimeUnit.SECONDS);
}
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("4秒后...");
scheduledExecutor.shutdown();
}
}
pool-1-thread-1 index:0 pool-1-thread-2 index:1 pool-1-thread-3 index:2 pool-1-thread-1 index:0 pool-1-thread-3 index:1 pool-1-thread-1 index:2 4秒后...
public class TestThreadPool {
//单线程的线程池，线程异常结束，会创建一个新的线程，能确保任务按提交顺序执行
static ExecutorService singleExecutor = Executors.newSingleThreadExecutor();
public static void main(String[] args) {
testSingleExecutor();
}
//测试单线程的线程池
private static void testSingleExecutor() {
for (int i = 0; i < 3; i ) {
final int index = i;
singleExecutor.execute(new Runnable() {
public void run() {
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() " index:" index);
}
});
}
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("4秒后...");
singleExecutor.shutdown();
}
}
pool-1-thread-1 index:0 4秒后... pool-1-thread-1 index:1 pool-1-thread-1 index:2
public class TestThreadPool {
//单线程可执行周期性任务的线程池
static ScheduledExecutorService singleScheduledExecutor = Executors.newSingleThreadScheduledExecutor();
public static void main(String[] args) {
testSingleScheduledExecutor();
}
//测试单线程可周期执行的线程池
private static void testSingleScheduledExecutor() {
for (int i = 0; i < 3; i ) {
final int index = i;
//scheduleWithFixedDelay 固定的延迟时间执行任务；scheduleAtFixedRate 固定的频率执行任务
singleScheduledExecutor.scheduleAtFixedRate(new Runnable() {
public void run() {
System.out.println(Thread.currentThread().getName() " index:" index);
}
}, 0, 3, TimeUnit.SECONDS);
}
try {
Thread.sleep(4000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("4秒后...");
singleScheduledExecutor.shutdown();
}
}
pool-1-thread-1 index:0 pool-1-thread-1 index:1 pool-1-thread-1 index:2 pool-1-thread-1 index:0 pool-1-thread-1 index:1 pool-1-thread-1 index:2 4秒后...
public class TestThreadPool {
//任务窃取线程池
static ExecutorService workStealingExecutor = Executors.newWorkStealingPool();
public static void main(String[] args) {
testWorkStealingExecutor();
}
//测试任务窃取线程池
private static void testWorkStealingExecutor() {
for (int i = 0; i < 10; i ) {//本机 CPU 8核，这里创建10个任务进行测试
final int index = i;
workStealingExecutor.execute(new Runnable() {
public void run() {
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread().getName() " index:" index);
}
});
}
try {
Thread.sleep(4000);//这里主线程不休眠，不会有打印输出
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println("4秒后...");
// workStealingExecutor.shutdown();
}
}
ForkJoinPool-1-worker-1 index:0 ForkJoinPool-1-worker-7 index:6 ForkJoinPool-1-worker-5 index:4 ForkJoinPool-1-worker-3 index:2 ForkJoinPool-1-worker-4 index:3 ForkJoinPool-1-worker-2 index:1 ForkJoinPool-1-worker-0 index:7 ForkJoinPool-1-worker-6 index:5 4秒后...