java - 加倍 System.out

Question

我想将 System.out 消息写入另一个 OutputStream，但我仍然想要标准输出。

我找到了类似问题的答案Copy and Redirecting System.err Stream :

In short what you need to do is define a PrintStream which can duplicate its output, assign this using:

System.setErr(doubleLoggingPrintStream)

这是我到目前为止所做的:

public class DoublerPrintStream extends PrintStream {

    private OutputStream forwarder;

    public DoublerPrintStream(OutputStream target, OutputStream forward) {
        super(target, true);
        this.forwarder = forward;
    }

    @Override
    public void write(byte[] b) throws IOException {
        try {
            synchronized (this) {
                super.write(b);
                forwarder.write(b);
                forwarder.flush();
            }
        }
        catch (InterruptedIOException x) {
            Thread.currentThread().interrupt();
        }
        catch (IOException x) {
        }
    }

    @Override
    public void write(byte[] buf, int off, int len) {
        try {
            synchronized (this) {
                super.write(buf, off, len);
                forwarder.write(buf, off, len);
                forwarder.flush();
            }
        }
        catch (InterruptedIOException x) {
            Thread.currentThread().interrupt();
        }
        catch (IOException x) {
        }
    }

    @Override
    public void write(int b) {
        try {
            synchronized (this) {
                super.write(b);
                forwarder.write(b);
                forwarder.flush();
            }
        }
        catch (InterruptedIOException x) {
            Thread.currentThread().interrupt();
        }
        catch (IOException x) {
        }
    }

    @Override
    public void flush() {
        super.flush();
        try { forwarder.flush(); } catch (IOException e) { }
    }

    @Override
    public void close() {
        super.close();
        if (forwarder != null) {
            try {
                forwarder.close();
            } catch (Exception e) {}
            }
        }
    }
}

这只是一个草案，但这是一个好方法吗？我不知道是否有更好的解决方案，所以我正在寻找确认、想法和建议。

Answer 1

我认为有一个 Apache 库可以做到这一点( TeeOutputStream ，谢谢@Thilo)，但你的实现对我来说看起来不错。