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我正在尝试使用 C# 将 JDF 文件转换为 PDF 文件。

查看JDF 格式后...我可以看到该文件只是一个放置在 PDF 文档顶部的 XML。

我尝试StreamWriter / StreamReader在 C# 中使用该功能，但由于 PDF 文档还包含二进制数据，并且可变换行符（\r\t 和 \t）生成的文件无法打开，因为某些二进制数据在 PDF 上被破坏。这是我尝试使用但没有成功的一些代码。

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);
        }
    }
}
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1 回答 1

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我自己回答这个问题，因为它可能是一个有点普遍的问题，并且解决方案可能对其他人有用。

由于文档包含二进制文件和文本，我们不能简单地使用 将StreamWriter二进制文件写回另一个文件。即使您使用StreamWriter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。

您可以使用BinaryWriter搜索多部分文档并将每个字节完全按照您找到的方式写入另一个文档。

//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BinaryReader1 逐 1 读取每个字符，如果找到匹配的字符串%PDF-（PDF 开始签名），它将把阅读器位置移回%，然后使用writer.Write(reader.ReadByte()).

于 2019-04-26T16:13:05.320 回答