需求
需要根据优先级执行任务，有任务不是特别重要，可以稍后执行；需要对正在执行的线程做超时监控；有的API依赖任务返回结果，线程池执行的时候任务也支持同步任务；
简单测试
创建一个使用支持优先级队列（new PriorityBlockingQueue<>() ）的线程，然后每个任务实现 java.lang.Comparable 接口
new ThreadPoolExecutor(MAX_THREAD, MAX_THREAD * 2, 0L, TimeUnit.MILLISECONDS, new PriorityBlockingQueue());
简单测试一下基本可行，但是发现使用优先级列队线程池发现使用FutureTask 会抛异常 java.lang.ClassCastException: java.util.concurrent.FutureTask cannot be cast to java.lang.Comparable 所以这个方法不能再用了
Future<?> future = executor.submit(new Task());1
设计思路
定义一个任务接口，继承 Runnable, Comparable，并且获取超时时间方法、优先级方法、执行时间方法、超时中止任务方法；
有一个管理线程池的类，用于执行任务
有一个超时检测的类
有一个基本执行类，用于每次任务执行时把任务加入监控列表，有一个同步任务类，管理执行同步任务
代码实现
任务接口
/**
* Created by zengrenyuan on 18/6/11.
*/public interface ExecuteTask extends Runnable, Comparable {
/**
* @return 任务超时时间
*/
long getTimeout(); /**
* @return 任务的优先级
*/
int getPriority(); /**
* 任务超时时调用
* 用于结束任务运行
*/
void destroy(); /**
* @return 任务当前的执行时间
*/
long elapsed();
}线程池管理
import org.slf4j.Logger;import org.slf4j.LoggerFactory;import javax.annotation.PreDestroy;import java.util.concurrent.*;/**
* Created by zengrenyuan on 18/06/11.
*/public class ExecuteThreadManager {
private static final Logger LOG = LoggerFactory.getLogger(ExecuteThreadManager.class); /**
* 线程池线程名称
*/
public static final String SCRIPT_TASK_THREAD_POOL = "TaskThreadPool"; /**
* 最大线程数
*/
private final int MAX_THREAD = 10; /**
* 一个按优先级执行的线程池
*/
private final ThreadPoolExecutor executor = ThreadPoolUtils.newThreadPool(MAX_THREAD, SCRIPT_TASK_THREAD_POOL, new PriorityBlockingQueue<>()); private static class LazyHolder {
private static final ExecuteThreadManager INSTANCE = new ExecuteThreadManager();
} private ExecuteThreadManager() {
} /**
* 单例
*/
public static final ExecuteThreadManager getInstance() { return LazyHolder.INSTANCE;
} /**
* 把任务提交到线程池执行
*/
public void execute(ExecuteTask task) {
executor.execute(new BaseExecuteTask(task));
} /**
* 同步执行任务，等任务执行完才会往下走
*/
public void syncExecute(ExecuteTask task) {
SynchronizedExecuteTask syncTask = new SynchronizedExecuteTask(task);
executor.execute(syncTask);
syncTask.await();
} @PreDestroy
private void destroy() { try {
executor.shutdownNow();
} catch (Exception e) {
LOG.error(null, e);
}
}
}线程池生成工具类
import java.util.concurrent.*;/**
* Created by zengrenyuan on 18/06/11.
*/public class ThreadPoolUtils {
/**
* 生成一个线程池
*
* @param maxThread 线程池最大数
* @param threadPoolName 线程池名称
* @return
*/
public static ThreadPoolExecutor newThreadPool(int maxThread, final String threadPoolName) { return newThreadPool(maxThread, threadPoolName, new LinkedBlockingDeque<>());
} /**
* 生成一个线程池
*
* @param maxThread 线程池最大数
* @param threadPoolName 线程池名称
* @param workQueue 队列
* @return 线程池
*/
public static ThreadPoolExecutor newThreadPool(int maxThread, final String threadPoolName, BlockingQueue workQueue) { return new ThreadPoolExecutor(
maxThread,
maxThread, 0L,
TimeUnit.MILLISECONDS,
workQueue,
getThreadFactory(threadPoolName)
);
} /**
* @param threadPoolName 线程名称
* @return 线程生成器
*/
public static ThreadFactory getThreadFactory(final String threadPoolName) { return new ThreadFactory() { private int threadNumber = 1; @Override
public Thread newThread(Runnable r) { return new Thread(r, threadPoolName + "-" + threadNumber);
}
};
}
}基础任务类
import org.slf4j.Logger;import org.slf4j.LoggerFactory;/**
* 简单包装一下
* 在任务执行前把任务加入到运行任务监控池
* Created by zengrenyuan on 18/06/11.
*/public class BaseExecuteTask implements ExecuteTask {
private static final Logger LOG = LoggerFactory.getLogger(BaseExecuteTask.class); protected ExecuteTask task; public BaseExecuteTask(ExecuteTask task) { this.task = task;
} @Override
public long getTimeout() { return task.getTimeout();
} @Override
public void destroy() {
task.destroy();
} @Override
public int getPriority() { return task.getPriority();
} @Override
public long elapsed() { return task.elapsed();
} @Override
public int compareTo(Object o) { return task.compareTo(o);
} @Override
public void run() { try { //任务开始前把任务加入到正在运行的任务池
TaskPoolListener.addTask(this);
task.run();
} finally {
LOG.info("运行结束");
TaskPoolListener.removeTask(this); //任务运行后，把任务从正在运行的任务池中移除
}
}
}同步线程工具类
import java.util.concurrent.CountDownLatch;import java.util.concurrent.TimeUnit;/**
* 同步执行任务
* Created by zengrenyuan on 18/06/11.
*/public class SynchronizedExecuteTask extends BaseExecuteTask {
private static final Logger LOG = LoggerFactory.getLogger(SynchronizedExecuteTask.class); //用于记录任务是否执行完成
private CountDownLatch latch = new CountDownLatch(1); public SynchronizedExecuteTask(ExecuteTask task) { super(task);
} @Override
public void run() { try { super.run();
} finally {
LOG.info("运行结束");
latch.countDown();
}
} public void await() { //任务是否在超时时间之前执行完成
boolean finished = false; try {
finished = latch.await(getTimeout(), TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
LOG.error(null, e);
} finally { if (!finished) {
destroy(); throw new RuntimeException("任务执行超时");
}
}
}
}任务超时监控
import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Service;import javax.annotation.PostConstruct;import java.util.ArrayList;import java.util.List;/**
* Created by zengrenyuan on 18/06/11.
*/@Servicepublic class TaskPoolListener {
private static final Logger LOG = LoggerFactory.getLogger(TaskPoolListener.class); private final static List<ExecuteTask> scriptTasks = new ArrayList<>(); public static final int SLEEP_INTERVAL = 10_000; private Thread thread; @PostConstruct
public void init() {
thread = new Thread(new Runnable() { @Override
public void run() { while (true) { try {
doTask();
} catch (Exception e) {
LOG.info(null, e);
} finally { this.sleep(SLEEP_INTERVAL);
}
}
} private void sleep(long interval) { try {
Thread.sleep(interval);
} catch (InterruptedException var4) {
LOG.info(var4.getMessage());
}
}
});
thread.setName("任务运行超时检测线程");
thread.start();
} /**
* 用于监测超时任务
* 如果任务超时调用destroy方法
*/
public void doTask() {
List<ExecuteTask> scriptTasks = new ArrayList<>(this.scriptTasks); for (ExecuteTask scriptTask : scriptTasks) { if (scriptTask.elapsed() > scriptTask.getTimeout()) {
scriptTask.destroy();
}
}
} public static synchronized void addTask(ExecuteTask scriptTask) {
scriptTasks.add(scriptTask);
} public static synchronized void removeTask(ExecuteTask scriptTask) {
scriptTasks.remove(scriptTask);
} public final int size() { return scriptTasks.size();
}
}
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