Java';s完全的未来和线程
我想用Java';s完全的未来和线程,java,multithreading,asynchronous,java-8,completable-future,Java,Multithreading,Asynchronous,Java 8,Completable Future,我想用CompletableFutureJava8-9启动线程,使用异步模式,这些是我的类和线程: 我有三条线。我的类包含一个方法myMethod() 设置我的Runnables,如下所示: Runnable runnableClass_1 = new Runnable(){ public void run(){ class_1.myMethod(); try { Thread.sleep(0); } catch (InterruptedException
CompletableFuture
Java8-9启动线程,使用异步模式,这些是我的类和线程:
我有三条线。我的类包含一个方法myMethod()
设置我的Runnable
s,如下所示:
Runnable runnableClass_1 = new Runnable(){
public void run(){
class_1.myMethod();
try { Thread.sleep(0); } catch (InterruptedException e) { e.printStackTrace(); }
}
};
Runnable runnableClass_2 = new Runnable(){
public void run(){
class_2.myMethod();
try { Thread.sleep(0); } catch (InterruptedException e) { e.printStackTrace(); }
}
};
Runnable runnableClass_3 = new Runnable(){
public void run(){
class_3.myMethod();
try { Thread.sleep(0); } catch (InterruptedException e) { e.printStackTrace(); }
}
};
创建线程:
Thread t_1 = new Thread( runnableClass_1 );
Thread t_2 = new Thread( runnableClass_2 );
Thread t_3 = new Thread( runnableClass_3 );
最后,我的问题是如何使用
CompletableFuture
异步模式启动这三个线程。以下是如何实现相同的线程:
List<String> results = new ArrayList<String>();
CompletableFuture<Void> run1 = CompletableFuture.runAsync(() -> {
pauseSeconds(2);
results.add("first task");
}, service);
CompletableFuture<Void> run2 = CompletableFuture.runAsync(() -> {
pauseSeconds(3);
results.add("second task");
}, service);
CompletableFuture<Void> finisher = run1.runAfterBothAsync(run2,
() -> results.add(results.get(0)+ "&"+results.get(1)),service);
pauseSeconds(4);
System.out.println("finisher.isDone() = "+finisher.isDone());
System.out.println("results.get(2) = "+results.get(2));
// assert(finisher.isDone(), is(true));
// assertThat(results.get(2),is("first task&second task"));
}
public static void pauseSeconds(int num){
try {
Thread.sleep(num);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
List results=new ArrayList();
CompletableFuture run1=CompletableFuture.runAsync(()->{
暂停秒(2);
结果。添加(“第一项任务”);
}(服务),;
CompletableFuture run2=CompletableFuture.runAsync(()->{
暂停秒(3);
结果。添加(“第二项任务”);
}(服务),;
CompletableFuture finisher=run1.runAfterBothAsync(run2,
()->results.add(results.get(0)+“&”+results.get(1)),服务);
暂停秒(4);
System.out.println(“finisher.isDone()=”+finisher.isDone());
System.out.println(“results.get(2)=”+results.get(2));
//断言(finisher.isDone(),is(true));
//资产(results.get(2)是(“第一个任务和第二个任务”);
}
公共静态无效暂停秒(int num){
试一试{
睡眠(num);
}捕捉(中断异常e){
//TODO自动生成的捕捉块
e、 printStackTrace();
}
}
如何设置(以及可能组合)未来取决于您的用例:这些未来相互依赖吗?您需要按顺序执行它们还是可以并行运行它们?你是关心这三个结果,还是只需要哪一个未来先完成
根据您的答案,您可以使用flatMap/bind
组合器(它们对CompletableFuture
有不同的名称,但您可以计算出来)按顺序链接您的未来,或者您可以从当前线程中生成所有未来(让它们并行运行),然后等待它们全部完成。您还可以指定特定的线程池,以CompletableFuture
just-use默认(ForkJoinPool)的工厂方法
所有这些都可以通过提供的Future
的一元版本非常简洁地完成。但是,如果您查看一下它的功能,您还可以使用CompletableFuture
提出一个解决方案
更新/请求示例:
下面的示例基本上取自,其中提供的期货并行运行,所有期货的结果都累积到一个集合中。您要做的是,将列表
转换为未来
如果您不需要自己控制线程处理,您可以简单地使用。如果需要更多控制,请使用带有
Executor
参数的版本,并自定义Executor
。最后,如果你真的需要使用这3个特定的线程,你必须在可运行的中管理CompletableFuture
自己。我感兴趣的是尽可能节省时间,在我使用CompletableFuture
之前,我的内存非常有限,所以我使用了顺序模式,现在我预告了我的备忘录,然后是处理器,我对在并行中使用completedlefuture
感兴趣,你能举个例子吗。我接受你的回答,原因是,我被允许进行一些修改,但你的主要方法得到了很好的保留,;)@YohanT Sry让你很困惑。当我谈论接受我的答案时,我指的是StackOverflow上的“接受答案”功能。您可以在此处阅读:
List<String> results = new ArrayList<String>();
CompletableFuture<Void> run1 = CompletableFuture.runAsync(() -> {
pauseSeconds(2);
results.add("first task");
}, service);
CompletableFuture<Void> run2 = CompletableFuture.runAsync(() -> {
pauseSeconds(3);
results.add("second task");
}, service);
CompletableFuture<Void> finisher = run1.runAfterBothAsync(run2,
() -> results.add(results.get(0)+ "&"+results.get(1)),service);
pauseSeconds(4);
System.out.println("finisher.isDone() = "+finisher.isDone());
System.out.println("results.get(2) = "+results.get(2));
// assert(finisher.isDone(), is(true));
// assertThat(results.get(2),is("first task&second task"));
}
public static void pauseSeconds(int num){
try {
Thread.sleep(num);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
final long startTime = System.currentTimeMillis();
final CompletableFuture<String> foo = CompletableFuture.supplyAsync(() -> {
final long timeout = 500;
try {
Thread.sleep(timeout);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(String.format("foo on %s sleeping for %s", Thread.currentThread(), timeout));
return "foo";
});
final CompletableFuture<String> bar = CompletableFuture.supplyAsync(() -> {
final long timeout = 100;
try {
Thread.sleep(timeout);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(String.format("bar on %s sleeping for %s", Thread.currentThread(), timeout));
return "bar";
});
final CompletableFuture<String> baz = CompletableFuture.supplyAsync(() -> {
final long timeout = 1000;
try {
Thread.sleep(timeout);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(String.format("baz on %s sleeping for %s", Thread.currentThread(), timeout));
return "baz";
});
CompletableFuture
.supplyAsync(() -> Stream.of(foo, bar, baz).map(future -> future.join()).collect(Collectors.toList()))
.thenAccept(done -> System.out.println(String.format("Done with all futures %s", done)))
.thenRun(() -> System.out.println(String.format("Running all futures in parallel took %s millis", System.currentTimeMillis() - startTime)));
bar on Thread[ForkJoinPool.commonPool-worker-2,5,main] sleeping for 100
foo on Thread[ForkJoinPool.commonPool-worker-9,5,main] sleeping for 500
baz on Thread[ForkJoinPool.commonPool-worker-11,5,main] sleeping for 1000
Done with all futures [foo, bar, baz]
Running all futures in parallel took 1007 millis