Java并行执行任务的几种方案小结

    private void assemblyActivityTag(CartItemDTO itemDTO){
        //1.查询立减活动信息，耗时1s         
        //2.查询阶梯满减活动信息，耗时1s        
        //3.查询团购活动信息，耗时1s        
        //4.组装活动标签信息，耗时1s 
        // 串行执行下来整个耗时4s
    }

    private void assemblyActivityTag(CartItemDTO itemDTO){
        ExecutorService executorService = Executors.newCachedThreadPool();
        CountDownLatch latch = new CountDownLatch(3);
        executorService.execute(new Runnable() {
            @Override
            public void run() {
            //1.查询立减活动信息
                latch.countDown();
            }
        });
        executorService.execute(new Runnable() {
            @Override
            public void run() {
                //2.查询阶梯满减活动信息
                latch.countDown();
            }
        });
        executorService.execute(new Runnable() {
            @Override
            public void run() {
                //3.查询团购活动信息
                latch.countDown();
            }
        });
        try {
            // 一定记得加上timeout时间，防止阻塞主线程
            latch.await(3000,TimeUnit.MILLISECONDS);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //4.等待所有子任务完成，组装活动标签信息
         
        //5.关闭线程池
        executorService.shutdown();
    }

private void assemblyActivityTag(CartItemDTO itemDTO) {
        ExecutorService executorService = Executors.newCachedThreadPool();
        List<Callable<String>> tasks = Lists.newArrayList();
        tasks.add(new Callable<String>() {
            @Override
            public String call() throws Exception {
                //1.查询立减活动信息
                return null;
            }
        });
        tasks.add(new Callable<String>() {
            @Override
            public String call() throws Exception {
                //2.查询阶梯满减活动信息
                return null;
            }
        });
        tasks.add(new Callable<String>() {
            @Override
            public String call() throws Exception {
                //3.查询团购活动信息
                return null;
            }
        });
        try {
            List<Future<String>> futureList = executorService.invokeAll(tasks, 3000, TimeUnit.MILLISECONDS);
            for (Future<String> future : futureList) {
                // 获取线程执行结果
                try {
                    String activityTag = future.get();
                } catch (ExecutionException e) {
                    e.printStackTrace();
                }
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        //4.组装活动标签信息
        //5.关闭线程池
        executorService.shutdown();
    }

package com.test.demo;
import org.junit.Test;
import java.util.concurrent.CompletableFuture;
public class TestFuture {
    @Test
    public void testA(){
        CompletableFuture<String> future3 = CompletableFuture.supplyAsync(() -> c());
        CompletableFuture<String> future1 = CompletableFuture.supplyAsync(() -> a());
        CompletableFuture<String> future2 = CompletableFuture.supplyAsync(() -> b());
        try {
            //获取并行执行任务结果
            System.out.println(future3.get());
            System.out.println(future1.get());
            System.out.println(future2.get());
        }catch (Exception e){
        }
    }
    public String a(){
        try {
            Thread.sleep(1000);
        }catch (Exception e){
        }
        return "a";
    }
    private String b(){
        try {
            //模拟业务执行时间
            Thread.sleep(2000);
        }catch (Exception e){
        }
        return "b";
    }
    private String c(){
        try {
            //模拟业务执行时间
            Thread.sleep(5000);
        }catch (Exception e){
        }
        return "c";
    }
}