JAVA多線程筆試題

一、題目內容

二、我的答案

　　利用了線程池、考慮了超時處理、不知道這樣寫是否還有其他問題，或者更好更優的解決方案？

import java.util.*;
import java.util.concurrent.*;

public class Main {

    public static void main(String[] args) {
        List<String> allPaymentList=Arrays.asList("余額","紅包","余額寶","銀行卡");
        long start=System.nanoTime();
        List<String> list=filterDisablePayment(allPaymentList);
        double seconds=(System.nanoTime()-start)/1000000000.0;
        System.out.println("總共耗時:"+seconds+"s");
        for(String paymentType:list){
            System.out.println(paymentType);
        }
    }


    public static List<String> filterDisablePayment(List<String> allPaymentList){
        List<String> results=new ArrayList<>();
        ExecutorService executorService= Executors.newFixedThreadPool(allPaymentList.size());
        List<Future<String>> futures=new ArrayList<>();
        for(String paymentType:allPaymentList) {
            futures.add(executorService.submit(new PaymentMethodCallable(paymentType)));
        }
        executorService.shutdown();
        for(Future<String> future:futures){
            try {
                //超時處理機制
                String result= future.get(4,TimeUnit.SECONDS);
                if(result!=null){
                    results.add(result);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return results;
    }


    public static Boolean PaymentIsEnabled(String paymentType) {
        try {
            //模擬遠程服務調用所用時間
            Thread.sleep(3000);
            Random random=new Random();
            boolean result=random.nextBoolean();
            System.out.println("獲取到結果:"+paymentType+":"+result);
            return result;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return false;
    }


    static class PaymentMethodCallable implements Callable<String> {

        private String paymentType;

        public String getPaymentType() {
            return paymentType;
        }

        public void setPaymentType(String paymentType) {
            this.paymentType = paymentType;
        }

        public PaymentMethodCallable(String paymentType) {
            this.paymentType = paymentType;
        }

        @Override
        public String call() {
            if(PaymentIsEnabled(paymentType)) return paymentType;
            return null;
        }
    }
}