【使用CompletableFuture进行多任务并行处理】话不多说，上代码！
package com.example.demo.research.async;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;
import java.util.function.Supplier;
public class CompletableFutureDemo {/**
* CPU核数
*/
private static final int AVAILABLE_PROCESSORS = Runtime.getRuntime().availableProcessors();
private static ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
AVAILABLE_PROCESSORS,//核心线程数
3 * AVAILABLE_PROCESSORS,//最大线程数
3, TimeUnit.SECONDS,//keepAliveTime
new LinkedBlockingDeque<>(20));
//阻塞队列public static void main(String[] args) throws Exception {
long startTime = System.currentTimeMillis();
System.out.println("demo start....." + startTime);
demo4();
System.out.println("demo end.....costTime = " + (System.currentTimeMillis() - startTime));
}/**
* 基于allOf，并行处理多个任务，等待所有任务执行完毕后返回
*/
public static void demo3() throws Exception {
//用于整体接收各个任务的返回值
Map dataMap = new HashMap<>();
List futureList = new ArrayList<>();
futureList.add(doSomethingA("A", dataMap));
futureList.add(doSomethingB("B", dataMap));
futureList.add(doSomethingC("C", dataMap));
CompletableFuture result = CompletableFuture.allOf(futureList.toArray(new CompletableFuture[futureList.size()]));
try {
result.get(2, TimeUnit.SECONDS);
} catch (Exception e) {
e.printStackTrace();
}System.out.println("result = " + dataMap);
//结果为：{doSomeThingB=B, doSomeThingA=A}
}/**
* 基于thenCompose，第一个任务执行完后，第二个任务使用第一个任务的返回作为参数
*/
public static void demo1() throws Exception {
Map dataMap = new HashMap<>();
CompletableFuture completableFuture = doSomethingA("A", dataMap)
.thenCompose(id -> doSomethingB(id, dataMap));
String result = completableFuture.get(2, TimeUnit.SECONDS);
System.out.println("result = " + result);
//结果为：A is done is done
}/**
* 基于thenCombine，当两个任务都完成后，使用两者的结果作为参数再执行一个异步任务
*/
public static void demo2() throws Exception {
Map dataMap = new HashMap<>();
CompletableFuture completableFuture = doSomethingA("A", dataMap)
.thenCombine(doSomethingB("B", dataMap), (a, b) -> a + " - " + b);
String result = completableFuture.get(2, TimeUnit.SECONDS);
System.out.println("result = " + result);
//结果为：A is done - B is done
}/**
* 使用CompletionService批量异步处理
*
* CompletionService 能够让异步任务的执行结果有序化，先执行完的先进入阻塞队列，
* 利用这个特性，你可以轻松实现后续处理的有序性，避免无谓的等待
*/
public static void demo4() {
Map dataMap = new HashMap<>();
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