Java7新特性（四）并发 7 ScheduledThreadPool

本文主要根据《Java程序员修炼之道》整理的代码笔记片段

工作单元

public class WorkUnit<T> {  private final T workUnit;  public T getWork() {    return workUnit;  }  public WorkUnit(T _workUnit) {  workUnit = _workUnit;  }}

计划线程池（启动、关闭、执行队列中工作单元）

public class ScheduledThreadPoolExecutorClass {private ScheduledExecutorService stpe;private ScheduledFuture<?> hndl;BlockingQueue<WorkUnit<String>> lbq =new LinkedBlockingQueue<>();private void run(){stpe = Executors.newScheduledThreadPool(2);final Runnable msgReader = new Runnable() {@Overridepublic void run() {String nextMsg = lbq.poll().getWork();if(nextMsg != null){System.out.println("Msg recvd: "+ nextMsg);}}};hndl =stpe.scheduleAtFixedRate(msgReader, 10, 10, TimeUnit.MILLISECONDS);}private void cancel(){final ScheduledFuture<?> myHndl = hndl;stpe.schedule(new Runnable() {@Overridepublic void run() {myHndl.cancel(true);}}, 10, TimeUnit.MILLISECONDS);}public static void main(String[] args) {ScheduledThreadPoolExecutorClass s = new ScheduledThreadPoolExecutorClass();for (int i = 0; i < 10; i++) {s.lbq.add(new WorkUnit<String>(i+""));}s.run();for (int i = 10; i < 20; i++) {s.lbq.add(new WorkUnit<String>(i+""));}}}

think in java 实例 Callable

/*The submit( ) method produces a Future object, parameterized for the particular type of result returned by the Callable. You can query the Future with isDone( ) to see if it has completed. When the task is completed and has a result, you can call get( ) to fetch the result. You can simply call get( ) without checking isDone( ),in which case get( ) will block until the result is ready. You can also call get( ) with a timeout, or isDone( ) to see if the task has completed,before trying to call get( ) to fetch the result.The overloaded Executors.callable( ) method takes a Runnable and produces a Callable. ExecutorService has some "invoke" methods that run collections of Callable objects.*/public class CallableDemo {public static void main(String[] args) {ExecutorService exec = Executors.newCachedThreadPool();ArrayList<Future<String>> results = new ArrayList<Future<String>>();for (int i = 0; i < 10; i++)results.add(exec.submit(new TaskWithResult(i)));for (Future<String> fs : results)try {// get() blocks until completion:System.out.println(fs.get());} catch (InterruptedException e) {System.out.println(e);return;} catch (ExecutionException e) {System.out.println(e);} finally {exec.shutdown();}}}class TaskWithResult implements Callable<String> {private int id;public TaskWithResult(int id) {this.id = id;}public String call() {return "result of TaskWithResult " + id;}}