Question

我正在尝试使用C＃将JDF文件转换为PDF文件。

查看JDF format ...之后，我可以看到该文件只是放置在PDF文档顶部的XML。

我尝试在C＃中使用StreamWriter / StreamReader功能，但是由于PDF文档还包含二进制数据以及可变换行符（\ r \ t和\ t），因此无法打开生成的文件，因为某些二进制数据在PDF上发行。这是我尝试使用但未成功的一些代码。

using (StreamReader reader = new StreamReader(_jdf.FullName, Encoding.Default))
{
    using (StreamWriter writer = new StreamWriter(_pdf.FullName, false, Encoding.Default))
    {

        writer.NewLine = "\n"; //Tried without this and with \r\n

        bool IsStartOfPDF = false;
        while (!reader.EndOfStream)
        {
            var line = reader.ReadLine();

            if (line.IndexOf("%PDF-") != -1)
            {
                IsStartOfPDF = true;
            }

            if (!IsStartOfPDF)
            {
                continue;
            }

            writer.WriteLine(line);
        }
    }
}

Answer 1

我正在回答这个问题，因为这可能是一个普遍的问题，解决方案可能对其他人有帮助。

由于文档同时包含二进制文件和文本，因此我们不能简单地使用StreamWriter将二进制文件写回到另一个文件。即使您使用StreamWriter来读取文件，然后将所有内容写入另一个文件，您也会意识到文档之间的差异。

您可以利用BinaryWriter来搜索包含多部分的文档，并将每个字节精确地写入到另一个文档中。

//Using a Binary Reader/Writer as the PDF is multitype
using (var reader = new BinaryReader(File.Open(_file.FullName, FileMode.Open)))
{
    using (var writer = new BinaryWriter(File.Open(tempFileName.FullName, FileMode.CreateNew)))
    {

        //We are searching for the start of the PDF 
        bool searchingForstartOfPDF = true;
        var startOfPDF = "%PDF-".ToCharArray();

        //While we haven't reached the end of the stream
        while (reader.BaseStream.Position != reader.BaseStream.Length)
        {
            //If we are still searching for the start of the PDF
            if (searchingForstartOfPDF)
            {
                //Read the current Char
                var str = reader.ReadChar();

                //If it matches the start of the PDF signiture
                if (str.Equals(startOfPDF[0]))
                {
                    //Check the next few characters to see if they match
                    //keeping an eye on our current position in the stream incase something goes wrong
                    var currBasePos = reader.BaseStream.Position;
                    for (var i = 1; i < startOfPDF.Length; i++)
                    {
                        //If we found a char that isn't in the PDF signiture, then resume the while loop
                        //to start searching again from the next position
                        if (!reader.ReadChar().Equals(startOfPDF[i]))
                        {
                            reader.BaseStream.Position = currBasePos;
                            break;
                        }
                        //If we've reached the end of the PDF signiture then we've found a match
                        if (i == startOfPDF.Length - 1)
                        {
                            //Success
                            //Set the Position to the start of the PDF signiture 
                            searchingForstartOfPDF = false;
                            reader.BaseStream.Position -= startOfPDF.Length;
                            //We are no longer searching for the PDF Signiture so 
                            //the remaining bytes in the file will be directly wrote
                            //using the stream writer
                        }
                    }
                }
            }
            else
            {
                //We are writing the binary now
                writer.Write(reader.ReadByte());
            }
        }

    }
}

此代码示例使用BinaryReader来按1读取每个字符，如果找到字符串%PDF-（PDF起始签名）的匹配项，它将读取器位置移回{ {1}}，然后使用%编写其余文档。

如何将JDF文件转换为PDF（从多编码文档中删除文本）

1 个答案: