Java8新特性：CompletableFuture 方法介紹

1. runAsync 和 supplyAsync方法

runAsync方法不支持返回值。
supplyAsync可以支持返回值。

public static CompletableFuture<Void> runAsync(Runnable runnable)
public static CompletableFuture<Void> runAsync(Runnable runnable, Executor executor)
public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier)
public static <U> CompletableFuture<U> supplyAsync(Supplier<U> supplier, Executor executor)

默認使用 ForkJoinPool.commonPool() 線程池執行，

runAsync使用(包含lambda調用方法)

	public static void runAsync() throws Exception {
		CompletableFuture<Void> future = CompletableFuture.runAsync(() -> {
			try {
				TimeUnit.SECONDS.sleep(1);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("執行完成");
		});
		future.get();
	}
	
	public static void runAsync2() throws Exception {
		CompletableFuture<Void> future = CompletableFuture.runAsync(new Runnable() {
			@Override
			public void run() {
				try {
					TimeUnit.SECONDS.sleep(1);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("執行完成");
			}
		});
		future.get();
	}

supplyAsync使用

	public static void supplyAsync() throws Exception {         
		CompletableFuture<Long> future = CompletableFuture.supplyAsync(() -> {
			try {
				TimeUnit.SECONDS.sleep(2);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("執行完成");
			return System.currentTimeMillis();
		});

		long time = future.get();
		System.out.println("time = "+time);
	}
	
	public static void supplyAsync2() throws Exception {         
		CompletableFuture<Long> future = CompletableFuture.supplyAsync(new Supplier<Long>() {
			@Override
			public Long get() {
				try {
					TimeUnit.SECONDS.sleep(2);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("執行完成");
				return System.currentTimeMillis();
			}
		});
		long time = future.get();
		System.out.println("time = "+time);
	}

2. whenComplete、whenCompleteAsync、exceptionally

計算完成後執行的回調方法

public CompletableFuture<T> whenComplete(BiConsumer<? super T,? super Throwable> action)
public CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T,? super Throwable> action)
public CompletableFuture<T> whenCompleteAsync(BiConsumer<? super T,? super Throwable> action, Executor executor)
public CompletableFuture<T> exceptionally(Function<Throwable,? extends T> fn)

whenComplete 和 whenCompleteAsync 的區別：

whenComplete：是執行當前任務的線程執行繼續執行 whenComplete 的任務。

whenCompleteAsync：是執行把 whenCompleteAsync 這個任務繼續提交給線程池來進行執行。

exceptionally：異常處理方法

	public static void whenComplete() throws Exception {
	    CompletableFuture<Void> future = CompletableFuture.runAsync(() -> {
	        try {
	            TimeUnit.SECONDS.sleep(1);
	        } catch (InterruptedException e) {
	        }
	        if(new Random().nextInt()%2>0) {
	            int i = 1/0;
	        }
	    });
	    
	    future.whenComplete(new BiConsumer<Void, Throwable>() {
	        @Override
	        public void accept(Void t, Throwable action) {
	            System.out.println("執行完成！");
	        }
	        
	    });
	    future.exceptionally(new Function<Throwable, Void>() {
	        @Override
	        public Void apply(Throwable t) {
	            System.out.println("執行失敗！"+t.getMessage());
	            return null;
	        }
	    });
	    
	    future.get();
	}
	
	
	public static void whenComplete2() throws Exception {
	   String string = CompletableFuture.supplyAsync(() -> {
	        try {
	            TimeUnit.SECONDS.sleep(1);
	        } catch (InterruptedException e) {
	        }
	        if(new Random().nextInt()%2>0) {
	            int i = 1/0;
	        }
	        return "返回結果";
	    }).whenComplete((value,throwable)->{
	    	if(throwable!=null) {
	    		System.out.println("異常："+throwable);
	    	}else {
	    		System.out.println("value:"+value);
	    	}
	    }).get();
	   System.out.println("執行完:"+string);
//	    future.exceptionally(new Function<Throwable, Void>() {
//	        @Override
//	        public Void apply(Throwable t) {
//	            System.out.println("執行失敗！"+t.getMessage());
//	            return null;
//	        }
//	    });
	    
	}

3. thenApply 、 handle

thenApply

串行執行，第二次執行需要依賴第一次的執行結果

	private static void thenApply() throws Exception {
		CompletableFuture<Integer> future = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				try {
					TimeUnit.SECONDS.sleep(1);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				if(new Random().nextInt()%2>0) {
					int i = 1/0;
				}
				return 10;
			}
		}).thenApply(new Function<Integer, Integer>() {
			@Override
			public Integer apply(Integer value) {
				System.out.println("上一步結果："+value);
				System.out.println("返回結果："+20);
				return 20;
			}
		}).exceptionally(new Function<Throwable, Integer>() {
			@Override
			public Integer apply(Throwable t) {
				System.out.println("異常返回："+ t);
				return -1;
			}
		});

		long result = future.get();
		System.out.println("最終結果："+result);
	}

	private static void thenApply2() throws Exception {
		Integer integer = CompletableFuture.supplyAsync(()->{
			try {
				TimeUnit.SECONDS.sleep(1);
			} catch (InterruptedException e) {
			}
			if(new Random().nextInt()%2>0) {
				int i = 1/0;
			}
			return 10;
		}).thenApply((value)->{
			System.out.println("上一步結果："+value);
			System.out.println("返回結果："+20);
			return 20;
		}).exceptionally((throwable)->{
			System.out.println("異常返回："+throwable);
			return -1;
		}).get();
		System.out.println("最終結果："+integer);
	}

handle

handle 是執行任務完成時對結果的處理。

handle 方法和 thenApply 方法處理方式基本一樣。不同的是 handle 是在任務完成後再執行，還可以處理異常的任務。thenApply 只可以執行正常的任務，任務出現異常則不執行 thenApply 方法。

public <U> CompletionStage<U> handle(BiFunction<? super T, Throwable, ? extends U> fn);
public <U> CompletionStage<U> handleAsync(BiFunction<? super T, Throwable, ? extends U> fn);
public <U> CompletionStage<U> handleAsync(BiFunction<? super T, Throwable, ? extends U> fn,Executor executor);

	public static void handle() throws Exception{
		CompletableFuture<Integer> future = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				int i= 10/0;
				return new Random().nextInt(10);
			}
		}).handle(new BiFunction<Integer, Throwable, Integer>() {
			@Override
			public Integer apply(Integer param, Throwable throwable) {
				int result = -1;
				if(throwable==null){
					result = param * 2;
				}else{
					System.out.println(throwable.getMessage());
				}
				return result;
			}
		});
		System.out.println(future.get());
	}
	public static void handle2() throws Exception{
		CompletableFuture<Integer> future = CompletableFuture.supplyAsync(()->{
			int i= 10/0;
			return new Random().nextInt(10);
		}).handle((value,throwable)->{
			int result = -1;
			if(throwable==null){
				result = value * 2;
			}else{
				System.out.println(throwable.getMessage());
			}
			return result;
		});
		System.out.println(future.get());
	}

4.thenAccept 、thenRun 方法消費處理結果

thenAccept

接收任務的處理結果，並消費處理，無返回結果。

public CompletionStage<Void> thenAccept(Consumer<? super T> action);
public CompletionStage<Void> thenAcceptAsync(Consumer<? super T> action);
public CompletionStage<Void> thenAcceptAsync(Consumer<? super T> action,Executor executor);

	public static void thenAccept() throws Exception{
		CompletableFuture<Void> future = CompletableFuture.supplyAsync(()->{
			return new Random().nextInt(10);
		}).thenAccept(integer -> {
			System.out.println(integer);
		});
		future.get();
	}
	public static void thenAccept2() throws Exception{
		CompletableFuture<Void> future = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				return new Random().nextInt(10);
			}
		}).thenAccept(new Consumer<Integer>() {
			@Override
			public void accept(Integer t) {
				System.out.println(t);
			}
		});
		future.get();
	}

thenRun

該方法同 thenAccept 方法類似。不同的是上個任務處理完成後，並不會把計算的結果傳給 thenRun 方法。只是處理完任務後，執行 thenAccept 的後續操作。

public CompletionStage<Void> thenRun(Runnable action);
public CompletionStage<Void> thenRunAsync(Runnable action);
public CompletionStage<Void> thenRunAsync(Runnable action,Executor executor);

	public static void thenRun() throws Exception{
		CompletableFuture<Void> future = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				return "第一步完成";
			}
		}).thenRun(new Runnable() {
			@Override
			public void run() {
				System.out.println("執行完成");
			}
		});
		future.get();
	}
	public static void thenRun2() throws Exception{
		CompletableFuture<Void> future = CompletableFuture.supplyAsync(()->{
			return "第一步完成";
		}).thenRun(() -> {
			System.out.println("執行完成");
		});
		future.get();
	}

5. thenCombine 、 thenAcceptBoth

合併兩個任務執行結果，進行操作

thenCombine

thenCombine 會把兩個 CompletionStage 的任務都執行完成後，把兩個任務的結果一塊交給 thenCombine 來處理。

public <U,V> CompletionStage<V> thenCombine(CompletionStage<? extends U> other,BiFunction<? super T,? super U,? extends V> fn);
public <U,V> CompletionStage<V> thenCombineAsync(CompletionStage<? extends U> other,BiFunction<? super T,? super U,? extends V> fn);
public <U,V> CompletionStage<V> thenCombineAsync(CompletionStage<? extends U> other,BiFunction<? super T,? super U,? extends V> fn,Executor executor);

	private static void thenCombine() throws Exception {
		CompletableFuture<String> future1 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				try {
					TimeUnit.SECONDS.sleep(2);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				return "hello";
			}
		});
		CompletableFuture<String> future2 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				return "world";
			}
		});
		CompletableFuture<String> result = future1.thenCombine(future2, new BiFunction<String, String, String>() {
			@Override
			public String apply(String t, String u) {
				return t+" "+u;
			}
		});
		System.out.println(result.get());
	}
	
	private static void thenCombine2() throws Exception {
		CompletableFuture<String> future1 = CompletableFuture.supplyAsync(()->{
			try {
				TimeUnit.SECONDS.sleep(2);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			return "hello";
		});
		CompletableFuture<String> future2 = CompletableFuture.supplyAsync(()->{
			return "world";
		});
		CompletableFuture<String> result = future1.thenCombine(future2, (v1,v2)->{
			return v1+" "+v2;
		});
		System.out.println(result.get());
	}

thenAcceptBoth

當兩個CompletionStage都執行完成後，把結果一塊交給thenAcceptBoth來進行消耗,

與 thenCombine 區別在於，thenAcceptBoth無返回值

public <U> CompletionStage<Void> thenAcceptBoth(CompletionStage<? extends U> other,BiConsumer<? super T, ? super U> action);
public <U> CompletionStage<Void> thenAcceptBothAsync(CompletionStage<? extends U> other,BiConsumer<? super T, ? super U> action);
public <U> CompletionStage<Void> thenAcceptBothAsync(CompletionStage<? extends U> other,BiConsumer<? super T, ? super U> action,     Executor executor);

	private static void thenAcceptBoth() throws Exception {
		CompletableFuture<String> future1 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				try {
					TimeUnit.SECONDS.sleep(2);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				return "hello";
			}
		});
		CompletableFuture<String> future2 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				return "world";
			}
		});
		future1.thenAcceptBoth(future2, new BiConsumer<String, String>() {
			@Override
			public void accept(String t, String u) {
				System.out.println( t+" "+u);
			}
		});
	}
	
	private static void thenAcceptBoth2() throws Exception {
		CompletableFuture<String> future1 = CompletableFuture.supplyAsync(()->{
			try {
				TimeUnit.SECONDS.sleep(2);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			return "hello";
		});
		CompletableFuture<String> future2 = CompletableFuture.supplyAsync(()->{
			return "world";
		});
		future1.thenAcceptBoth(future2, (v1,v2)->{
			System.out.println( v1+" "+v2);
		});
	}

6.applyToEither 、 acceptEither

兩個CompletionStage，誰執行返回的結果快，就用那個CompletionStage的結果進行下一步的轉化操作。

applyToEither 有返回值，acceptEither 無返回值

applyToEither

public <U> CompletionStage<U> applyToEither(CompletionStage<? extends T> other,Function<? super T, U> fn);
public <U> CompletionStage<U> applyToEitherAsync(CompletionStage<? extends T> other,Function<? super T, U> fn);
public <U> CompletionStage<U> applyToEitherAsync(CompletionStage<? extends T> other,Function<? super T, U> fn,Executor executor);

	private static void applyToEither() throws Exception {
		CompletableFuture<Integer> f1 = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				int t = new Random().nextInt(3);
				try {
					TimeUnit.SECONDS.sleep(t);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("f1="+t);
				return t;
			}
		});
		CompletableFuture<Integer> f2 = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				int t = new Random().nextInt(3);
				try {
					TimeUnit.SECONDS.sleep(t);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("f2="+t);
				return t;
			}
		});

		CompletableFuture<Integer> result = f1.applyToEither(f2, new Function<Integer, Integer>() {
			@Override
			public Integer apply(Integer t) {
				System.out.println(t);
				return t * 2;
			}
		});
		System.out.println("結果："+result.get());
	}
	
	private static void applyToEither2() throws Exception {
		CompletableFuture<Integer> f1 = CompletableFuture.supplyAsync(()->{
			int t = new Random().nextInt(3);
			try {
				TimeUnit.SECONDS.sleep(t);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("f1="+t);
			return t;
		});
		CompletableFuture<Integer> f2 = CompletableFuture.supplyAsync(()->{
			int t = new Random().nextInt(3);
			try {
				TimeUnit.SECONDS.sleep(t);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("f2="+t);
			return t;
		});

		CompletableFuture<Integer> result = f1.applyToEither(f2, (value)->{
			System.out.println(value);
			return value * 2;
		});
		System.out.println("結果："+result.get());
	}

acceptEither

public CompletionStage<Void> acceptEither(CompletionStage<? extends T> other,Consumer<? super T> action);
public CompletionStage<Void> acceptEitherAsync(CompletionStage<? extends T> other,Consumer<? super T> action);
public CompletionStage<Void> acceptEitherAsync(CompletionStage<? extends T> other,Consumer<? super T> action,Executor executor);

	private static void acceptEither() throws Exception {
		CompletableFuture<Integer> f1 = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				int t = new Random().nextInt(3);
				try {
					TimeUnit.SECONDS.sleep(t);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("f1="+t);
				return t;
			}
		});

		CompletableFuture<Integer> f2 = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				int t = new Random().nextInt(3);
				try {
					TimeUnit.SECONDS.sleep(t);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("f2="+t);
				return t;
			}
		});
		CompletableFuture<Void> acceptEither = f1.acceptEither(f2, new Consumer<Integer>() {
			@Override
			public void accept(Integer t) {
				System.out.println("結果："+t);
			}
		});
	}
	
	private static void acceptEither2() throws Exception {
		CompletableFuture<Integer> f1 = CompletableFuture.supplyAsync(()->{
			int t = new Random().nextInt(3);
			try {
				TimeUnit.SECONDS.sleep(t);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("f1="+t);
			return t;
		});

		CompletableFuture<Integer> f2 = CompletableFuture.supplyAsync(()->{
			int t = new Random().nextInt(3);
			try {
				TimeUnit.SECONDS.sleep(t);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("f2="+t);
			return t;
		});
		CompletableFuture<Void> acceptEither = f1.acceptEither(f2, (value)->{
			System.out.println("結果："+value);
		});
	}

7. runAfterEither 、 runAfterBoth

runAfterEither

兩個CompletionStage，任何一個完成了都會執行下一步的操作

public CompletionStage<Void> runAfterEither(CompletionStage<?> other,Runnable action);
public CompletionStage<Void> runAfterEitherAsync(CompletionStage<?> other,Runnable action);
public CompletionStage<Void> runAfterEitherAsync(CompletionStage<?> other,Runnable action,Executor executor);

	private static void runAfterEither() throws Exception {
		CompletableFuture<Integer> f1 = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				int t = new Random().nextInt(3);
				try {
					TimeUnit.SECONDS.sleep(t);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("f1="+t);
				return t;
			}
		});

		CompletableFuture<Integer> f2 = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				int t = new Random().nextInt(3);
				try {
					TimeUnit.SECONDS.sleep(t);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("f2="+t);
				return t;
			}
		});
		f1.runAfterEither(f2, new Runnable() {

			@Override
			public void run() {
				System.out.println("上面有一個已經完成了。");
			}
		}).get();
	}
	
	private static void runAfterEither1() throws Exception {
		CompletableFuture<Integer> f1 = CompletableFuture.supplyAsync(()->{
			int t = new Random().nextInt(3);
			try {
				TimeUnit.SECONDS.sleep(t);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("f1="+t);
			return t;
		});

		CompletableFuture<Integer> f2 = CompletableFuture.supplyAsync(()->{
			int t = new Random().nextInt(3);
			try {
				TimeUnit.SECONDS.sleep(t);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("f2="+t);
			return t;
		});
		f1.runAfterEither(f2, ()->{System.out.println("上面有一個已經完成了。");}).get();
	}

runAfterBoth

兩個CompletionStage，都完成了計算纔會執行下一步的操作

public CompletionStage<Void> runAfterBoth(CompletionStage<?> other,Runnable action);
public CompletionStage<Void> runAfterBothAsync(CompletionStage<?> other,Runnable action);
public CompletionStage<Void> runAfterBothAsync(CompletionStage<?> other,Runnable action,Executor executor);

	private static void runAfterBoth() throws Exception {
		CompletableFuture<Integer> f1 = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				int t = new Random().nextInt(3);
				try {
					TimeUnit.SECONDS.sleep(t);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("f1="+t);
				return t;
			}
		});

		CompletableFuture<Integer> f2 = CompletableFuture.supplyAsync(new Supplier<Integer>() {
			@Override
			public Integer get() {
				int t = new Random().nextInt(3);
				try {
					TimeUnit.SECONDS.sleep(t);
				} catch (InterruptedException e) {
					e.printStackTrace();
				}
				System.out.println("f2="+t);
				return t;
			}
		});
		f1.runAfterBoth(f2, new Runnable() {

			@Override
			public void run() {
				System.out.println("上面兩個任務都執行完成了。");
			}
		}).get();
	}

	private static void runAfterBoth2() throws Exception {
		CompletableFuture<Integer> f1 = CompletableFuture.supplyAsync(()->{
			int t = new Random().nextInt(3);
			try {
				TimeUnit.SECONDS.sleep(t);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("f1="+t);
			return t;
		});

		CompletableFuture<Integer> f2 = CompletableFuture.supplyAsync(()->{
			int t = new Random().nextInt(3);
			try {
				TimeUnit.SECONDS.sleep(t);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("f2="+t);
			return t;
		});
		f1.runAfterBoth(f2, ()->{
			System.out.println("上面兩個任務都執行完成了。");
		}).get();
	}

8.complete

runAsync 執行完成則以該結果爲準；如果未執行完成時執行complete，則返回complete值

	public static void complete() throws Exception {
		CompletableFuture<Integer> runAsync = CompletableFuture.supplyAsync(()->{
			try {
				TimeUnit.SECONDS.sleep(1);
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			System.out.println("run end ...");
			return 1;
		});
		TimeUnit.SECONDS.sleep(2);
		// runAsync 執行完成則以該結果爲準；如果未執行完成時執行complete，則返回complete值
		runAsync.complete(-1);
		System.out.println("success:"+ runAsync.get());
	}

9.allOf 多實例同時返回、anyOf 多實例一個執行完成返回

allOf

在這裏我們可以將對各future實例添加到allOf方法中，然後通過future的get()方法獲取future的狀態。如果allOf裏面的所有線程爲執行完畢，主線程會阻塞，直到allOf裏面的所有線程都執行，線程就會被喚醒。

		CompletableFuture<String> future1 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				try {
					TimeUnit.SECONDS.sleep(2);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				return "hello";
			}
		});
		CompletableFuture<String> future2 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				return "world";
			}
		});
		CompletableFuture<String> future3 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				try {
					TimeUnit.SECONDS.sleep(5);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				return "!!!";
			}
		});
		long currentTimeMillis = System.currentTimeMillis();
		System.out.println(future1.isDone()+" "+future2.isDone()+" "+future3.isDone());
		CompletableFuture<Void> allOf = CompletableFuture.allOf(future1,future2,future3);
		allOf.get();//這裏會等待三個任務都執行完成
		System.out.println("執行完成,時間："+(System.currentTimeMillis()-currentTimeMillis));
		System.out.println(future1.isDone()+" "+future2.isDone()+" "+future3.isDone());

anyOf

調用方法與allOf基本相同，區別在於anyOf是，其中一個執行完成則往下執行

anyOf get()方法返回最先執行完的Future

		CompletableFuture<String> future1 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				try {
					TimeUnit.SECONDS.sleep(2);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				return "hello";
			}
		});
		CompletableFuture<String> future2 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				try {
					TimeUnit.SECONDS.sleep(2);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				return "world";
			}
		});
		CompletableFuture<String> future3 = CompletableFuture.supplyAsync(new Supplier<String>() {
			@Override
			public String get() {
				try {
					TimeUnit.SECONDS.sleep(5);
				} catch (InterruptedException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
				return "!!!";
			}
		});
		long currentTimeMillis = System.currentTimeMillis();
		System.out.println(future1.isDone()+" "+future2.isDone()+" "+future3.isDone());
		//		CompletableFuture<Void> allOf = CompletableFuture.allOf(future1,future2,future3);
		//		allOf.thenAccept((x)->{
		//			System.out.println("123:"+x);
		//		}).get();

		CompletableFuture<Object> anyOf = CompletableFuture.anyOf(future1,future2,future3);

		System.out.println("結果："+anyOf.get());
		System.out.println("執行完成,時間："+(System.currentTimeMillis()-currentTimeMillis));
		System.out.println(future1.isDone()+" "+future2.isDone()+" "+future3.isDone());

10.所有方法 Async 與非Async 區別

比如：thenApply與thenApplyAsync 等等

參考：https://blog.csdn.net/leon_wzm/article/details/80560081

public static void main(String[] args) throws Exception {
		async1();
		async2();
		async3();
	}
	public static void async1() throws Exception {
		CompletableFuture<String> future1 = CompletableFuture.supplyAsync(()->{
			try {
				TimeUnit.SECONDS.sleep(2);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			System.out.println("supplyAsync："+Thread.currentThread().getName() +" "+Thread.currentThread().getId());
			return "hello";
		});
		TimeUnit.SECONDS.sleep(5);
		CompletableFuture<Integer> thenApply = future1.thenApply((x)->{
			System.out.println("thenApply："+Thread.currentThread().getName() +" "+Thread.currentThread().getId());
			return 1;
		});
		thenApply.get();
	}

	public static void async2() throws Exception {
		CompletableFuture<String> future1 = CompletableFuture.supplyAsync(()->{
			try {
				TimeUnit.SECONDS.sleep(2);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			System.out.println("supplyAsync："+Thread.currentThread().getName() +" "+Thread.currentThread().getId());
			return "hello";
		});
		CompletableFuture<Integer> thenApply = future1.thenApply((x)->{
			System.out.println("thenApply："+Thread.currentThread().getName() +" "+Thread.currentThread().getId());
			return 1;
		});
		thenApply.get();
	}

	public static void async3() throws Exception {
		CompletableFuture<String> future1 = CompletableFuture.supplyAsync(()->{
			try {
				TimeUnit.SECONDS.sleep(2);
			} catch (InterruptedException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
			System.out.println("supplyAsync："+Thread.currentThread().getName() +" "+Thread.currentThread().getId());
			return "hello";
		});
		TimeUnit.SECONDS.sleep(5);
		CompletableFuture<Integer> thenApply = future1.thenApplyAsync((x)->{
			System.out.println("thenApply："+Thread.currentThread().getName() +" "+Thread.currentThread().getId());
			return 1;
		});
		thenApply.get();
	}

Java8新特性：CompletableFuture 方法介紹

1. runAsync 和 supplyAsync方法

2. whenComplete、whenCompleteAsync、exceptionally

3. thenApply 、 handle

thenApply

handle

4.thenAccept 、thenRun 方法消費處理結果

thenAccept

thenRun

5. thenCombine 、 thenAcceptBoth

thenCombine

thenAcceptBoth

6.applyToEither 、 acceptEither

applyToEither

acceptEither

7. runAfterEither 、 runAfterBoth

runAfterEither

runAfterBoth

8.complete

9.allOf 多實例同時返回、anyOf 多實例一個執行完成返回

allOf

anyOf

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Java8新特性：CompletableFuture 方法介紹

1. runAsync 和 supplyAsync方法

2. whenComplete、whenCompleteAsync、exceptionally

3. thenApply 、 handle

thenApply

handle

4.thenAccept 、thenRun 方法 消費處理結果

thenAccept

thenRun

5. thenCombine 、 thenAcceptBoth

thenCombine

thenAcceptBoth

6.applyToEither 、 acceptEither

applyToEither

acceptEither

7. runAfterEither 、 runAfterBoth

runAfterEither

runAfterBoth

8.complete

9.allOf 多實例同時返回 、anyOf 多實例一個執行完成返回

allOf

anyOf

4.thenAccept 、thenRun 方法消費處理結果

9.allOf 多實例同時返回、anyOf 多實例一個執行完成返回