方法说明
| 方法 | 说明 |
|---|---|
| setCorePoolSize | 设置线程池核心线程数量，会一直存在。可以在运行时修改。若未设置，则默认为 1 。 |
| getCorePoolSize | 获取核心线程数量 |
| setMaxPoolSize | 设置最大线程数量。可以在运行时修改。若未设置，则默认为 Integer.MAX_VALUE。 |
| getMaxPoolSize | 获取最大线程数量 |
| setKeepAliveSeconds | 设置线程空闲后的存活时间，单位秒。可以在运行时修改。若未设置，则默认为 60 。 |
| getKeepAliveSeconds | 获取线程存活时间 |
| setQueueCapacity | 设置任务队列容量。正数，则用 LinkedBlockingQueue 作为队列；其他情况下用 SynchronousQueue 做队列。若未设置，则默认为 Integer.MAX_VALUE。 |
| setAllowCoreThreadTimeOut | 设置是否允许核心线程超时。若允许，核心线程超时后，会被销毁。默认为不允许（fasle）。 |
| setTaskDecorator | 设置任务装饰器 |
| getThreadPoolExecutor | 获取包装的底层 java.util.concurrent.ThreadPoolExecutor |
| getPoolSize | 获取线程池线程数量 |
| getActiveCount | 获取线程池活动中的线程数量 |
| setWaitForTasksToCompleteOnShutdown | 设置shutdown时是否等到所有任务完成再真正关闭 |
| setAwaitTerminationSeconds | 当 setWaitForTasksToCompleteOnShutdown(true)时，setAwaitTerminationSeconds 设置在 shutdown 之后最多等待多长时间后再真正关闭线程池 |
| initialize | 初始化线程池 |
| execute | 执行任务 |
| submit | 提交任务，返回 Future |
| shutdown | 关闭/销毁线程池 |
| destroy | 关闭/销毁线程池，底层直接调用的 shutdown |
| getThreadPoolExecutor().getQueue().size() | 获取任务队列中任务数量，即未执行的任务数量 |
示例1: 使用入门
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ThreadPoolExecutor;
public class TestThreadPool {
public static void main(String[] args) throws InterruptedException {
ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
threadPoolTaskExecutor.setThreadNamePrefix("xxxx-");
threadPoolTaskExecutor.setCorePoolSize(1);
threadPoolTaskExecutor.setMaxPoolSize(5);
threadPoolTaskExecutor.setQueueCapacity(10000);
threadPoolTaskExecutor.setKeepAliveSeconds(300);
threadPoolTaskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy() {
@Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
System.out.println("丢弃");
}
});
threadPoolTaskExecutor.initialize();
int taskNum = 10;
CountDownLatch latch = new CountDownLatch(taskNum);
for (int i=0; i < taskNum; i++) {
final int taskId = i;
System.out.println("-- submit task " + taskId);
threadPoolTaskExecutor.execute(() -> {
try {
System.out.printf("task: %s, thread: %s, start at %d\n", taskId, Thread.currentThread().getName(), System.currentTimeMillis()/1000);
Thread.sleep(2_000);
System.out.printf("task: %s, thread: %s, end at %d\n", taskId, Thread.currentThread().getName(), System.currentTimeMillis()/1000);
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
latch.countDown();
}
});
}
latch.await();
threadPoolTaskExecutor.shutdown();
}
}
运行结果：
-- submit task 0
-- submit task 1
-- submit task 2
-- submit task 3
-- submit task 4
task: 0, thread: xxxx-1, start at 1578795725
-- submit task 5
-- submit task 6
-- submit task 7
-- submit task 8
-- submit task 9
task: 0, thread: xxxx-1, end at 1578795727
task: 1, thread: xxxx-1, start at 1578795727
task: 1, thread: xxxx-1, end at 1578795729
task: 2, thread: xxxx-1, start at 1578795729
task: 2, thread: xxxx-1, end at 1578795731
task: 3, thread: xxxx-1, start at 1578795731
task: 3, thread: xxxx-1, end at 1578795733
task: 4, thread: xxxx-1, start at 1578795733
task: 4, thread: xxxx-1, end at 1578795735
task: 5, thread: xxxx-1, start at 1578795735
task: 5, thread: xxxx-1, end at 1578795737
task: 6, thread: xxxx-1, start at 1578795737
task: 6, thread: xxxx-1, end at 1578795739
task: 7, thread: xxxx-1, start at 1578795739
task: 7, thread: xxxx-1, end at 1578795741
task: 8, thread: xxxx-1, start at 1578795741
task: 8, thread: xxxx-1, end at 1578795743
task: 9, thread: xxxx-1, start at 1578795743
task: 9, thread: xxxx-1, end at 1578795745
示例2: 如果工作中线程数量达到 CorePoolSize ，任务队列已满，对于新任务会新开线程执行。总线程数不会超过 MaxPoolSize
这也意味着，即使任务队列不为空，部分后来的任务，会先被执行。
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ThreadPoolExecutor;
public class TestThreadPool {
public static void main(String[] args) throws InterruptedException {
ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
threadPoolTaskExecutor.setThreadNamePrefix("xxxx-");
threadPoolTaskExecutor.setCorePoolSize(1);
threadPoolTaskExecutor.setMaxPoolSize(5);
threadPoolTaskExecutor.setQueueCapacity(5);
threadPoolTaskExecutor.setKeepAliveSeconds(300);
threadPoolTaskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy() {
@Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
System.out.println("丢弃");
}
});
threadPoolTaskExecutor.initialize();
int taskNum = 10;
CountDownLatch latch = new CountDownLatch(taskNum);
for (int i=0; i < taskNum; i++) {
final int taskId = i;
System.out.println("-- submit task " + taskId);
threadPoolTaskExecutor.execute(() -> {
try {
System.out.printf("task: %s, thread: %s, start at %d\n", taskId, Thread.currentThread().getName(), System.currentTimeMillis()/1000);
Thread.sleep(2_000);
System.out.printf("task: %s, thread: %s, end at %d\n", taskId, Thread.currentThread().getName(), System.currentTimeMillis()/1000);
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
latch.countDown();
}
});
}
latch.await();
threadPoolTaskExecutor.shutdown();
}
}
执行结果：
-- submit task 0
-- submit task 1
-- submit task 2
-- submit task 3
-- submit task 4
task: 0, thread: xxxx-1, start at 1578795897
-- submit task 5
-- submit task 6
-- submit task 7
task: 6, thread: xxxx-2, start at 1578795897
task: 7, thread: xxxx-3, start at 1578795897
-- submit task 8
-- submit task 9
task: 8, thread: xxxx-4, start at 1578795897
task: 9, thread: xxxx-5, start at 1578795897
task: 6, thread: xxxx-2, end at 1578795899
task: 0, thread: xxxx-1, end at 1578795899
task: 7, thread: xxxx-3, end at 1578795899
task: 2, thread: xxxx-1, start at 1578795899
task: 1, thread: xxxx-2, start at 1578795899
task: 9, thread: xxxx-5, end at 1578795899
task: 8, thread: xxxx-4, end at 1578795899
task: 5, thread: xxxx-4, start at 1578795899
task: 4, thread: xxxx-5, start at 1578795899
task: 3, thread: xxxx-3, start at 1578795899
task: 2, thread: xxxx-1, end at 1578795901
task: 1, thread: xxxx-2, end at 1578795901
task: 5, thread: xxxx-4, end at 1578795901
task: 4, thread: xxxx-5, end at 1578795901
task: 3, thread: xxxx-3, end at 1578795901
示例3: 若 MaxPoolSize 小于 CorePoolSize，会报异常
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ThreadPoolExecutor;
public class TestThreadPool {
public static void main(String[] args) throws InterruptedException {
ThreadPoolTaskExecutor threadPoolTaskExecutor = new ThreadPoolTaskExecutor();
threadPoolTaskExecutor.setThreadNamePrefix("xxxx-");
threadPoolTaskExecutor.setCorePoolSize(8);
threadPoolTaskExecutor.setMaxPoolSize(5);
threadPoolTaskExecutor.setQueueCapacity(5);
threadPoolTaskExecutor.setKeepAliveSeconds(300);
threadPoolTaskExecutor.setRejectedExecutionHandler(new ThreadPoolExecutor.DiscardPolicy() {
@Override
public void rejectedExecution(Runnable r, ThreadPoolExecutor e) {
System.out.println("丢弃");
}
});
threadPoolTaskExecutor.initialize();
}
}
运行时报错如下：
Exception in thread "main" java.lang.IllegalArgumentException
at java.util.concurrent.ThreadPoolExecutor.<init>(ThreadPoolExecutor.java:1314)