java中的简单超时

Question

任何人都可以指导我如何在java中使用简单的超时？基本上在我的项目中我正在执行一个语句br.readLine(),它正在读取调制解调器的响应.但有时调制解调器没有响应.为此我想添加一个超时.我正在寻找像这样的代码:

try {
    String s= br.readLine();
} catch(TimeoutException e) {
    System.out.println("Time out has occurred");
}

Answer 1

你在寻找什么可以在这里找到.可能存在一种更优雅的方式来实现这一点,但一种可能的方法是

选项1(首选):

final Duration timeout = Duration.ofSeconds(30);
ExecutorService executor = Executors.newSingleThreadExecutor();

final Future<String> handler = executor.submit(new Callable() {
    @Override
    public String call() throws Exception {
        return requestDataFromModem();
    }
});

try {
    handler.get(timeout.toMillis(), TimeUnit.MILLISECONDS);
} catch (TimeoutException e) {
    handler.cancel(true);
}

executor.shutdownNow();

选项2:

final Duration timeout = Duration.ofSeconds(30);
ScheduledExecutorService executor = Executors.newScheduledThreadPool(1);

final Future<String> handler = executor.submit(new Callable() {
    @Override
    public String call() throws Exception {
        return requestDataFromModem();
    }
});

executor.schedule(new Runnable() {
    @Override
    public void run(){
        handler.cancel(true);
    }      
}, timeout.toMillis(), TimeUnit.MILLISECONDS);

executor.shutdownNow();

这些只是一个草案,所以你可以得到主要的想法.