在Java中，如何将System.out重定向到null然后再返回到stdout？ [英] In Java, how can I redirect System.out to null then back to stdout again?

问题描述

我尝试使用以下代码暂时将System.out重定向到/ dev / null但它不起作用。

I've tried to temporarily redirect System.out to /dev/null using the following code but it doesn't work.

System.out.println("this should go to stdout");

PrintStream original = System.out;
System.setOut(new PrintStream(new FileOutputStream("/dev/null")));
System.out.println("this should go to /dev/null");

System.setOut(original);
System.out.println("this should go to stdout"); // This is not getting printed!!!

任何人都有任何想法？

推荐答案

男，这不太好，因为Java是跨平台的，'/ dev / null'是Unix特有的（显然在Windows上有一个替代方案，阅读评论）。因此，您最好的选择是创建一个自定义OutputStream来禁用输出。

Man, this is not so good, because Java is cross-platform and '/dev/null' is Unix specific (apparently there is an alternative on Windows, read the comments). So your best option is to create a custom OutputStream to disable output.

try {
    System.out.println("this should go to stdout");

    PrintStream original = System.out;
    System.setOut(new PrintStream(new OutputStream() {
                public void write(int b) {
                    //DO NOTHING
                }
            }));
    System.out.println("this should go to /dev/null, but it doesn't because it's not supported on other platforms");

    System.setOut(original);
    System.out.println("this should go to stdout");
}
catch (Exception e) {
    e.printStackTrace();
}

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