java 线程池的使用

public ThreadPoolExecutor(int corePoolSize,
int maximumPoolSize,
long keepAliveTime,
TimeUnit unit,
BlockingQueue<Runnable> workQueue) {
this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,
Executors.defaultThreadFactory(), defaultHandler);
}

public ThreadPoolExecutor(int corePoolSize,
int maximumPoolSize,
long keepAliveTime,
TimeUnit unit,
BlockingQueue<Runnable> workQueue,
ThreadFactory threadFactory) {
this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,
threadFactory, defaultHandler);
}

public ThreadPoolExecutor(int corePoolSize,
int maximumPoolSize,
long keepAliveTime,
TimeUnit unit,
BlockingQueue<Runnable> workQueue,
RejectedExecutionHandler handler) {
this(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue,
Executors.defaultThreadFactory(), handler);
}

public ThreadPoolExecutor(int corePoolSize,
int maximumPoolSize,
long keepAliveTime,
TimeUnit unit,
BlockingQueue<Runnable> workQueue,
ThreadFactory threadFactory,
RejectedExecutionHandler handler) {
if (corePoolSize < 0 ||
maximumPoolSize <= 0 ||
maximumPoolSize < corePoolSize ||
keepAliveTime < 0)
throw new IllegalArgumentException();
if (workQueue == null || threadFactory == null || handler == null)
throw new NullPointerException();
this.corePoolSize = corePoolSize;
this.maximumPoolSize = maximumPoolSize;
this.workQueue = workQueue;
this.keepAliveTime = unit.toNanos(keepAliveTime);
this.threadFactory = threadFactory;
this.handler = handler;
}

AbortPolicy//抛出异常

DiscardPolicy  //丢弃任务

DiscardOldestPolicy  //丢弃最前面的任务，然后执行新的任务

CallerRunsPolicy  //由线程处理任务

public void execute(Runnable command)

Future<?> submit(Runnable task);

<T> Future<T> submit(Runnable task, T result);

Future<?> submit(Runnable task);

package com.example;

import com.example.utils.LogUtils;

import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;

/**
* @author xuanyouwu
* @email xuanyouwu@163.com
* @time 2016-05-04 16:38
*/
public class ThreadPoolStudy {
static ThreadPoolExecutor threadPoolExecutor;
public static void main(String[] args) throws Exception {

threadPoolExecutor = new ThreadPoolExecutor(3, 10, 2, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(3));

for (int i = 0; i < 100; i++) {
threadPoolExecutor.execute(new Task());
}
}

static class Task implements Runnable {

@Override
public void run() {
LogUtils.d("------>excute:Thread:" + Thread.currentThread().getId()+"   PoolSiz:"+threadPoolExecutor.getPoolSize()+"  ActiveCount:"+threadPoolExecutor.getActiveCount()+"  queueSize:"
+threadPoolExecutor.getQueue().size()+"   CompletedTaskCount:"+threadPoolExecutor.getCompletedTaskCount());
try {
Thread.currentThread().sleep(3000);
} catch (InterruptedException e) {
}
}
}
}

public static ExecutorService newWorkStealingPool() {
return new ForkJoinPool
(Runtime.getRuntime().availableProcessors(),
ForkJoinPool.defaultForkJoinWorkerThreadFactory,
null, true);
}

可惜是java 1.8才有的

推荐下面几种写法:

/**
* return new ThreadPoolExecutor(0, Integer.MAX_VALUE,
60L, TimeUnit.SECONDS,
new SynchronousQueue<Runnable>());
*/
Executors.newCachedThreadPool();

/**
*    return new ThreadPoolExecutor(nThreads, nThreads,
0L, TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<Runnable>());
*/
Executors.newFixedThreadPool(100);

/**
*  return new FinalizableDelegatedExecutorService
(new ThreadPoolExecutor(1, 1,
0L, TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<Runnable>()));
*/
Executors.newSingleThreadExecutor();

ExecutorService executorService = Executors.newCachedThreadPool();
for(int i=0;i<50;i++)
{
executorService.execute(new Runnable() {
@Override
public void run() {
try {
Thread.currentThread().sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
LogUtils.d("---------->Thread:"+Thread.currentThread().getId());
}
});
}

ExecutorService executorService = Executors.newFixedThreadPool(3);
for(int i=0;i<50;i++)
{
executorService.execute(new Runnable() {
@Override
public void run() {
try {
Thread.currentThread().sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
LogUtils.d("---------->Thread:"+Thread.currentThread().getId());
}
});
}
executorService.shutdown();

executorService=Executors.newSingleThreadExecutor();
for(int i=0;i<50;i++)
{
executorService.execute(new Runnable() {
@Override
public void run() {
try {
Thread.currentThread().sleep(2000);
} catch (InterruptedException e) {
e.printStackTrace();
}
LogUtils.d("---------->Thread:"+Thread.currentThread().getId());
}
});
}
executorService.shutdown();

/**
* The minimum priority that a thread can have.
*/
public final static int MIN_PRIORITY = 1;

/**
* The default priority that is assigned to a thread.
*/
public final static int NORM_PRIORITY = 5;

/**
* The maximum priority that a thread can have.
*/
public final static int MAX_PRIORITY = 10;

设置线程的优先级需要ThreadFacotry

 ThreadFactory threadFactory_MAX_PRIORITY = new ThreadFactory() {@Overridepublic Thread newThread(Runnable r) {Thread thread = new Thread(r);thread.setPriority(Thread.MAX_PRIORITY);return thread;}};ThreadFactory threadFactory_MIN_PRIORITY = new ThreadFactory() {@Overridepublic Thread newThread(Runnable r) {Thread thread = new Thread(r);thread.setPriority(Thread.MIN_PRIORITY);return thread;}};ThreadFactory threadFactory_NORMAL_PRIORITY = new ThreadFactory() {@Overridepublic Thread newThread(Runnable r) {Thread thread = new Thread(r);thread.setPriority(Thread.NORM_PRIORITY);return thread;}};ExecutorService executorService_MAX = Executors.newCachedThreadPool(threadFactory_MAX_PRIORITY);for (int i = 0; i < 10; i++) {executorService_MAX.execute(new Runnable() {@Overridepublic void run() {try {Thread.currentThread().sleep(2000);} catch (InterruptedException e) {e.printStackTrace();}LogUtils.d("---------->Thread:" + Thread.currentThread().getId() + "  threadPripiry:" + Thread.currentThread().getPriority());}});}executorService_MAX.shutdown();ExecutorService executorService_NOR = Executors.newCachedThreadPool(threadFactory_NORMAL_PRIORITY);for (int i = 0; i < 10; i++) {executorService_NOR.execute(new Runnable() {@Overridepublic void run() {try {Thread.currentThread().sleep(2000);} catch (InterruptedException e) {e.printStackTrace();}LogUtils.d("---------->Thread:" + Thread.currentThread().getId() + "  threadPripiry:" + Thread.currentThread().getPriority());}});}executorService_NOR.shutdown();ExecutorService executorService_MIN = Executors.newCachedThreadPool(threadFactory_MIN_PRIORITY);for (int i = 0; i < 10; i++) {executorService_MIN.execute(new Runnable() {@Overridepublic void run() {try {Thread.currentThread().sleep(2000);} catch (InterruptedException e) {e.printStackTrace();}LogUtils.d("---------->Thread:" + Thread.currentThread().getId() + "  threadPripiry:" + Thread.currentThread().getPriority());}});}executorService_MIN.shutdown();