有没有一种方法可以在Swing应用程序中保留打印机设置？

Question

我们正在使用新的Java打印API,用于PrinterJob.printDialog(attributes)向用户显示对话框.

想要下次保存用户的设置,我想这样做:

PrintRequestAttributeSet attributes = loadAttributesFromPreferences();
if (printJob.printDialog(attributes)) {
    // print, and then...

    saveAttributesToPreferences(attributes);
}

但是,我通过这样做发现,有时候(我还没弄清楚)属性是如何在内部获得一些不良数据,然后当你打印时,你会得到一个什么都没有的白页.然后代码将中毒的设置保存到首选项中,并且所有后续的打印运行也会中毒设置.此外,练习的整个点,使新运行的设置与用户为上一次运行选择的设置相同,将被取消,因为新对话框似乎不使用旧设置.

所以我想知道是否有正确的方法来做到这一点.当然,Sun并不打算用户每次启动应用程序时都必须选择打印机,页面大小,方向和边距设置.

编辑以显示存储方法的实现:

private PrintRequestAttributeSet loadAttributesFromPreferences()
{
    PrintRequestAttributeSet attributes = null;

    byte[] marshaledAttributes = preferences.getByteArray(PRINT_REQUEST_ATTRIBUTES_KEY, null);
    if (marshaledAttributes != null)
    {
        try
        {
            @SuppressWarnings({"IOResourceOpenedButNotSafelyClosed"})
            ObjectInput objectInput = new ObjectInputStream(new ByteArrayInputStream(marshaledAttributes));

            attributes = (PrintRequestAttributeSet) objectInput.readObject();
        }
        catch (IOException e)
        {
            // Can occur due to invalid object data e.g. InvalidClassException, StreamCorruptedException
            Logger.getLogger(getClass()).warn("Error trying to read print attributes from preferences", e);
        }
        catch (ClassNotFoundException e)
        {
            Logger.getLogger(getClass()).warn("Class not found trying to read print attributes from preferences", e);
        }
    }

    if (attributes == null)
    {
        attributes = new HashPrintRequestAttributeSet();
    }

    return attributes;
}

private void saveAttributesToPreferences(PrintRequestAttributeSet attributes)
{
    ByteArrayOutputStream storage = new ByteArrayOutputStream();
    try
    {
        ObjectOutput objectOutput = new ObjectOutputStream(storage);
        try
        {
            objectOutput.writeObject(attributes);
        }
        finally
        {
            objectOutput.close(); // side-effect of flushing the underlying stream
        }
    }
    catch (IOException e)
    {
        throw new IllegalStateException("I/O error writing to a stream going to a byte array", e);
    }

    preferences.putByteArray(PRINT_REQUEST_ATTRIBUTES_KEY, storage.toByteArray());
}

编辑:好的,似乎它不记得打印机的原因是它根本不在PrintRequestAttributeSet中.实际上,记住边距和页面大小,至少在设置随机中毒之前.但是用户选择的打印机不在此处:

[0] = {java.util.HashMap$Entry@9494} class javax.print.attribute.standard.Media -> na-letter
[1] = {java.util.HashMap$Entry@9501} class javax.print.attribute.standard.Copies -> 1
[2] = {java.util.HashMap$Entry@9510} class javax.print.attribute.standard.MediaPrintableArea -> (10.0,10.0)->(195.9,259.4)mm
[3] = {java.util.HashMap$Entry@9519} class javax.print.attribute.standard.OrientationRequested -> portrait

Answer 1

看来您正在寻找的是 PrintServiceAttributeSet ，而不是PrintRequestAttributeSet.

查看PrintServiceAttribute接口，看看您需要的元素是否已作为类实现。如果没有，您可以实现自己的PrintServiceAttribute类。