package com.chezhibao.mockserver.mulitithread;
import lombok.extern.slf4j.Slf4j;
import java.util.Random;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeUnit;
/**
* @author hepei
* @date 2019/8/26 10:05
**/
@Slf4j
public class CompletableFutureDemo {
/***
* 無返回值
*/
private static void runAsync() throws ExecutionException, InterruptedException {
log.info("start ...{}", System.currentTimeMillis() );
CompletableFuture<Void> future = CompletableFuture.runAsync( () -> {
try {
TimeUnit.SECONDS.sleep( 1 );
} catch (InterruptedException ignored) {
}
log.info("end .....{}", System.currentTimeMillis() );
} );
future.get();
}
/***
* 有返回值
*/
private static void supplyAsync() throws ExecutionException, InterruptedException {
log.info("start ...{}", System.currentTimeMillis() );
CompletableFuture<Long> future = CompletableFuture.supplyAsync( () -> {
try {
TimeUnit.SECONDS.sleep( 1 );
} catch (InterruptedException ignored) {
}
log.info("end .....{}", System.currentTimeMillis() );
return System.currentTimeMillis();
} );
Long aLong = future.get();
log.info("currentTime:{}", System.currentTimeMillis());
}
private static void whenComplete() throws InterruptedException {
CompletableFuture<Void> future = CompletableFuture.runAsync( () -> {
try {
TimeUnit.SECONDS.sleep( 1 );
} catch (InterruptedException ignored) {
}
log.info("start ...{}", System.currentTimeMillis() );
int i = 1 / 0;
} );
// 執行當前任務的線程執行繼續執行 whenComplete 的任務
future.whenComplete( (aVoid, throwable) -> log.info("執行完成{}", throwable.getMessage()) );
//當future執行發生異常後執行
future.exceptionally( throwable -> {
log.info("執行發生異常:{}", throwable.getMessage());
return null;
} );
TimeUnit.SECONDS.sleep( 2 );
}
/***
* 第二個任務依賴第一個任務的結果
* thenApply 只可以執行正常的任務,任務出現異常則不執行 thenApply 方法
*/
private static void thenApply() throws ExecutionException, InterruptedException {
CompletableFuture<Long> future = CompletableFuture.supplyAsync( () -> {
long data = new Random().nextInt( 100 );
log.info("data1=:{}", data);
return data;
} ).thenApply( t -> {
long data = t * 10;
log.info("data2=:{}", data);
return data;
} ).exceptionally( throwable -> {
log.info("執行發生異常:{}", throwable.getMessage());
return 0L;
} );
long result = future.get();
log.info("thenApply執行結果:{}", result);
}
/***
* 任務完成後再執行,還可以處理異常的任務
*/
private static void handle() throws ExecutionException, InterruptedException {
CompletableFuture<Long> future = CompletableFuture.supplyAsync( () -> {
int i = 10 / 0;
return new Random().nextLong();
} ).handle( (param, throwable) -> {
Long result = -1L;
if (throwable == null) {
result = param * 10;
} else {
log.info("執行發生異常:{}", throwable.getMessage());
}
return result;
} );
log.info("handle執行結果:{}", future.get());
}
/***
* 接收任務的處理結果,並消費處理,無返回結果。
*/
private static void thenAccept() throws ExecutionException, InterruptedException {
CompletableFuture<Void> future = CompletableFuture.supplyAsync( () -> new Random().nextInt( 1000 ) ).
thenAccept( aLong -> log.info("thenAccept接收aLong值:{}",aLong) );
future.get();
}
/***
* 不關心任務的處理結果。只要上面的任務執行完成,就開始執行 thenRun 。
*/
private static void thenRun() throws ExecutionException, InterruptedException {
CompletableFuture future = CompletableFuture.supplyAsync( () -> new Random().nextInt( 10 ) ).thenRun( () -> log.info("開始執行thenRun()"));
future.get();
}
/***
* 把兩個任務的結果一塊交給 thenCombine 來處理
*/
private static void thenCombine() throws ExecutionException, InterruptedException {
CompletableFuture<String> future1 = CompletableFuture.supplyAsync( () -> "then" );
CompletableFuture<String> future2 = CompletableFuture.supplyAsync( () -> "Combine" );
CompletableFuture<String> data = future1.thenCombine( future2, (s, s2) -> s + " " + s2 );
log.info("thenCombine執行結果:{}",data.get());
}
/***
* 當兩個CompletionStage都執行完成後,把結果一塊交給thenAcceptBoth來進行消耗
*/
private static void thenAcceptBoth() {
CompletableFuture<Integer> future1 = CompletableFuture.supplyAsync( () -> {
int t = new Random().nextInt( 3 );
try {
TimeUnit.SECONDS.sleep( t );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future1結果:{}",t);
return t;
} );
CompletableFuture<Integer> future2 = CompletableFuture.supplyAsync( () -> {
int t = new Random().nextInt( 3 );
try {
TimeUnit.SECONDS.sleep( t );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future2結果:{}",t);
return t;
} );
future1.thenAcceptBoth( future2, (integer, integer2) -> log.info("thenAcceptBoth:當兩個任務都執行完後彙總," +
" future1結果:{},future2的結果:{}",integer,integer2) );
}
/***
* 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。
*/
private static void applyToEither() {
CompletableFuture<Integer> future1 = CompletableFuture.supplyAsync( () -> {
int t = new Random().nextInt( 4 );
try {
TimeUnit.SECONDS.sleep( t );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future1結果:{}",t);
return t;
} );
CompletableFuture<Integer> future2 = CompletableFuture.supplyAsync( () -> {
int t = new Random().nextInt( 4 );
try {
TimeUnit.SECONDS.sleep( t );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future2結果:{}",t);
return t;
} );
CompletableFuture<Integer> result = future1.applyToEither( future2, t -> {
log.info("applyToEither接收到第一個完成任務的結果是:{}",t);
return t * 2;
} );
log.info( "applyToEither最終結果是:{}",result );
}
/***
* 兩個CompletionStage,誰執行返回的結果快,我就用那個CompletionStage的結果進行下一步的消耗操作。
*/
private static void acceptEither() {
CompletableFuture<Integer> future1 = CompletableFuture.supplyAsync( () -> {
int t = new Random().nextInt( 5 );
try {
TimeUnit.SECONDS.sleep( t );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future1結果:{}",t);
return t;
} );
CompletableFuture<Integer> future2 = CompletableFuture.supplyAsync( () -> {
int t = new Random().nextInt( 5 );
try {
TimeUnit.SECONDS.sleep( t );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future2結果:{}",t);
return t;
} );
future1.acceptEither( future2, t -> log.info("acceptEither接收到第一個完成任務的結果是:{}",t) );
}
/***
* 兩個CompletionStage,任何一個完成了都會執行下一步的操作
*/
private static void runAfterEither() {
CompletableFuture<Integer> future1 = CompletableFuture.supplyAsync( () -> {
int t = new Random().nextInt( 2 );
try {
TimeUnit.SECONDS.sleep( t );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future1結果:{}",t);
return t;
} );
CompletableFuture<Integer> future2 = CompletableFuture.supplyAsync( () -> {
int t = new Random().nextInt( 2 );
try {
TimeUnit.SECONDS.sleep( t );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future2結果:{}",t);
return t;
} );
future1.runAfterEither( future2, () -> log.info("只要有一個任務執行結束,我就會被執行到") );
}
/***
* 兩個CompletionStage,都完成了計算纔會執行下一步的操作
*/
private static void runAfterBoth() throws ExecutionException, InterruptedException {
CompletableFuture<Integer> fu1 = CompletableFuture.supplyAsync( () -> {
int time = new Random().nextInt( 3 );
try {
TimeUnit.SECONDS.sleep( time+1 );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future1結果:{}",time);
return time;
} );
CompletableFuture<Integer> fu2 = CompletableFuture.supplyAsync( () -> {
int time = new Random().nextInt( 3 );
try {
TimeUnit.SECONDS.sleep( time+1 );
} catch (InterruptedException e) {
e.printStackTrace();
}
log.info("future2結果:{}",time);
return time;
} );
fu1.get();
fu2.get();
fu1.runAfterBoth( fu2, () -> log.info("當兩個任務都執行結束,我就會被執行到") );
}
/***
* thenCompose 方法允許你對兩個 CompletionStage 進行流水線操作,第一個操作完成時,將其結果作爲參數傳遞給第二個操作。
*/
private static void thenCompose() throws ExecutionException, InterruptedException {
CompletableFuture<Integer> future = CompletableFuture.supplyAsync( () -> {
int r = new Random().nextInt( 5 );
log.info("future1結果:{}",r);
return r;
} ).thenCompose( param -> CompletableFuture.supplyAsync( () -> {
int r = param * 10;
log.info("thenCompose執行結果:{}",r);
return r;
} ) );
log.info("thenCompose執行結果:{}",future.get());
}
public static void main(String[] args) throws ExecutionException, InterruptedException {
runAsync();
supplyAsync();
whenComplete();
thenApply();
handle();
thenAccept();
thenRun();
thenCombine();
thenAcceptBoth();
applyToEither();
acceptEither();
runAfterEither();
runAfterBoth();
thenCompose();
}
}
JDK8 多線程 JUC之CompletableFuture使用
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