经常会有客户问到如何操作PDF文件的元数据信息，比如标题、主题、作者、关键字等？以下是java语言的代码示例：

String[] kMetadataItems = {"Title", "Author", "Subject", "Keywords",
        "Creator", "Producer", "CreationDate", "ModDate"};

String[] kMetadataValues = {"Title set by simple demo", "Simple demo",
        "Subject set by simple demo", "Keywords set by simple demo",
        "Foxit PDF SDK", "Foxit"};
Metadata metadata = new Metadata(doc);
for (int i = 0; i < kMetadataValues.length; i++) {
    WStringArray MetadataValues = new WStringArray();
    MetadataValues.add(kMetadataValues[i]);
    metadata.setValues(kMetadataItems[i], MetadataValues);
}
metadata.setCreationDateTime(GetLocalDateTime());
metadata.setModifiedDateTime(GetLocalDateTime());

通过以上代码示例，您可将想输入的标题、主题、作者、关键字等的元数据信息填充至PDF文件。