CompletionService 線程池結果處理

使用說明：

public static void eventSend(){
        List<String> list = Arrays.asList(new String[]{"1","2","3"});
        List<String> result = new ArrayList<>();
        ThreadPoolExecutor executor =null;
        try {
            executor = new ThreadPoolExecutor(10, 20, 60L, TimeUnit.SECONDS,new LinkedBlockingQueue<>());
            CompletionService<String> completionService = new ExecutorCompletionService<String>(executor);
            for (String systemCode: list) {
                String domain =systemCode;
                completionService.submit(new Callable<String>(){
                    @Override
                    public String call() throws Exception {
                        System.out.println("start:"+domain);
                        Thread.sleep(10000);
                        System.out.println("domain:"+domain);
                        return domain;
                    }
                });
            }
            System.out.println("循環完成");
            for (int i=0;i<list.size();i++){
                System.out.println("獲取結果開始"+i);
                Future<String> future = completionService.take();
                result.add(future.get());
            }
            System.out.println("獲取結果完成");
        } catch (Exception e) {
            e.printStackTrace();
        }finally {
            if(null!=executor){
                executor.shutdown();
            }
        }



        System.out.println("result:"+result.stream().collect(Collectors.joining(",")));

    }

結果：

循環完成
start:1
start:2
start:3
獲取結果開始0
domain:2
domain:1
獲取結果開始1
獲取結果開始2
domain:3
獲取結果完成
result:2,1,3