我看过很多帖子帮助我了解了我的情况，我是编程新手。我的目的是获取目录中的文件＆＃34; sourceDir＆＃34;并寻找正则表达式匹配。当它找到匹配时，我想创建一个以匹配作为名称的新文件。如果代码找到具有相同匹配的另一个文件（该文件已存在），则在该文档中创建一个新页面。
现在代码可以工作，但是它不会添加新页面，而是覆盖文档的第一页。注意：目录中的每个文档只有一页！
string sourceDir = @"C:\Users\bob\Desktop\results\";
string destDir = @"C:\Users\bob\Desktop\results\final\";
string[] files = Directory.GetFiles(sourceDir);
foreach (string file in files)
{
using (var pdfReader = new PdfReader(file.ToString()))
{
for (int page = 1; page <= pdfReader.NumberOfPages; page++)
{
var text = new StringBuilder();
ITextExtractionStrategy strategy = new SimpleTextExtractionStrategy();
var currentText =
PdfTextExtractor.GetTextFromPage(pdfReader, page, strategy);
currentText = Encoding.UTF8.GetString(Encoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText)));
text.Append(currentText);
Regex reg = new Regex(@"ABCDEFG");
MatchCollection matches = reg.Matches(currentText);
foreach (Match m in matches)
{
string newFile = destDir + m.ToString() + ".pdf";
if (!File.Exists(newFile))
{
using (PdfReader reader = new PdfReader(File.ReadAllBytes(file)))
{
using (Document doc = new Document(reader.GetPageSizeWithRotation(page)))
{
using (PdfCopy copy = new PdfCopy(doc, new FileStream(newFile, FileMode.Create)))
{
var importedPage = copy.GetImportedPage(reader, page);
doc.Open();
copy.AddPage(importedPage);
doc.Close();
}
}
}
}
else
{
using (PdfReader reader = new PdfReader(File.ReadAllBytes(newFile)))
{
using (Document doc = new Document(reader.GetPageSizeWithRotation(page)))
{
using (PdfCopy copy = new PdfCopy(doc, new FileStream(newFile, FileMode.OpenOrCreate)))
{
var importedPage = copy.GetImportedPage(reader, page);
doc.Open();
copy.AddPage(importedPage);
doc.Close();
}
}
}
}
}
}
}
}
答案 0 :(得分：2)
Bruno做了很好的解释问题以及如何解决这个问题，但是因为你已经说过你是编程的新手并且你已经进一步posted a very similar and related question我要走了希望能帮助你更深一点。
首先，让我们记下这些知识：
然后目标：
在继续操作之前，您需要了解一些事项。你尝试过＆＃34;追加模式＆＃34;使用FileMode.OpenOrCreate。这是一个很好的猜测，但不正确。 PDF格式既有开头也有结尾，所以＆＃34;从这里开始＆＃34;和＆＃34;在这里结束＆＃34;。当您尝试将另一个PDF（或其他任何内容）附加到现有文件时，您只需要通过＆＃34; end here＆＃34;部分。充其量，这些垃圾数据会被忽略，但更有可能最终导致损坏的PDF。几乎任何文件格式都是如此。连接的两个XML文件无效，因为XML文档只能有一个根元素。
第二个但相关，iText / iTextSharp无法编辑现有文件。这是非常重要的。但是，它可以创建恰好具有其他文件的确切或可能修改版本的全新文件。我不知道我是否可以强调这是多么重要。
第三，您正在使用一次又一次复制的行，但是非常错误，实际上可能会损坏您的数据。为什么它不好，read this。
currentText = Encoding.UTF8.GetString(Encoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText)));
第四，您正在使用RegEx，这是一种执行搜索的过于复杂的方式。也许您发布的代码只是一个示例，但如果不是，我建议您只使用currentText.Contains("")或者如果您需要忽略案例currentText.IndexOf( "", StringComparison.InvariantCultureIgnoreCase )。为了怀疑，下面的代码假设您有一个更复杂的RegEx。
尽管如此，下面是一个完整的工作示例，应该引导您完成所有事情。由于我们无法访问您的PDF，因此第二部分实际上会创建100个示例PDF，并偶尔会添加我们的搜索字词。你真正的代码显然不会这样做但我们需要共同的基础来与你合作。第三部分是您尝试执行的搜索和合并功能。希望代码中的注释能够解释所有内容。
/**
* Step 1 - Variable Setup
*/
//This is the folder that we'll be basing all other directory paths on
var workingFolder = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
//This folder will hold our PDFs with text that we're searching for
var folderPathContainingPdfsToSearch = Path.Combine(workingFolder, "Pdfs");
var folderPathContainingPdfsCombined = Path.Combine(workingFolder, "Pdfs Combined");
//Create our directories if they don't already exist
System.IO.Directory.CreateDirectory(folderPathContainingPdfsToSearch);
System.IO.Directory.CreateDirectory(folderPathContainingPdfsCombined);
var searchText1 = "ABC";
var searchText2 = "DEF";
/**
* Step 2 - Create sample PDFs
*/
//Create 100 sample PDFs
for (var i = 0; i < 100; i++) {
using (var fs = new FileStream(Path.Combine(folderPathContainingPdfsToSearch, i.ToString() + ".pdf"), FileMode.Create, FileAccess.Write, FileShare.None)) {
using (var doc = new Document()) {
using (var writer = PdfWriter.GetInstance(doc, fs)) {
doc.Open();
//Add a title so we know what page we're on when we combine
doc.Add(new Paragraph(String.Format("This is page {0}", i)));
//Add various strings every once in a while.
//(Yes, I know this isn't evenly distributed but I haven't
// had enough coffee yet.)
if (i % 10 == 3) {
doc.Add(new Paragraph(searchText1));
} else if (i % 10 == 6) {
doc.Add(new Paragraph(searchText2));
} else if (i % 10 == 9) {
doc.Add(new Paragraph(searchText1 + searchText2));
} else {
doc.Add(new Paragraph("Blah blah blah"));
}
doc.Close();
}
}
}
}
/**
* Step 3 - Search and merge
*/
//We'll search for two different strings just to add some spice
var reg = new Regex("(" + searchText1 + "|" + searchText2 + ")");
//Loop through each file in the directory
foreach (var filePath in Directory.EnumerateFiles(folderPathContainingPdfsToSearch, "*.pdf")) {
using (var pdfReader = new PdfReader(filePath)) {
for (var page = 1; page <= pdfReader.NumberOfPages; page++) {
//Get the text from the page
var currentText = PdfTextExtractor.GetTextFromPage(pdfReader, page, new SimpleTextExtractionStrategy());
currentText.IndexOf( "", StringComparison.InvariantCultureIgnoreCase )
//DO NOT DO THIS EVER!! See this for why https://stackoverflow.com/a/10191879/231316
//currentText = Encoding.UTF8.GetString(Encoding.Convert(Encoding.Default, Encoding.UTF8, Encoding.Default.GetBytes(currentText)));
//Match our pattern against the extracted text
var matches = reg.Matches(currentText);
//Bail early if we can
if (matches.Count == 0) {
continue;
}
//Loop through each match
foreach (var m in matches) {
//This is the file path that we want to target
var destFile = Path.Combine(folderPathContainingPdfsCombined, m.ToString() + ".pdf");
//If the file doesn't already exist then just copy the file and move on
if (!File.Exists(destFile)) {
System.IO.File.Copy(filePath, destFile);
continue;
}
//The file exists so we're going to "append" the page
//However, writing to the end of file in Append mode doesn't work,
//that would be like "add a file to a zip" by concatenating two
//two files. In this case, we're actually creating a brand new file
//that "happens" to contain the original file and the matched file.
//Instead of writing to disk for this new file we're going to keep it
//in memory, delete the original file and write our new file
//back onto the old file
using (var ms = new MemoryStream()) {
//Use a wrapper helper provided by iText
var cc = new PdfConcatenate(ms);
//Open for writing
cc.Open();
//Import the existing file
using (var subReader = new PdfReader(destFile)) {
cc.AddPages(subReader);
}
//Import the matched file
//The OP stated a guarantee of only 1 page so we don't
//have to mess around with specify which page to import.
//Also, PdfConcatenate closes the supplied PdfReader so
//just use the variable pdfReader.
using (var subReader = new PdfReader(filePath)) {
cc.AddPages(subReader);
}
//Close for writing
cc.Close();
//Erase our exisiting file
File.Delete(destFile);
//Write our new file
File.WriteAllBytes(destFile, ms.ToArray());
}
}
}
}
}
答案 1 :(得分：0)
我将用伪代码写这个。
你做这样的事情：
// loop over different single-page documents
for () {
// introduce a condition
if (condition == met) {
// create single-page PDF
new Document();
new PdfCopy();
document.Open();
copy.add(singlePage);
document.Close();
}
}
这意味着您每次满足条件时都要创建单页PDF。顺便说一下，您多次覆盖现有文件。
你应该做什么，是这样的：
// Create a document with as many pages as times a condition is met
new Document();
new PdfCopy();
document.Open();
// loop over different single-page documents
for () {
// introduce a condition
if (condition == met) {
copy.addPage(singlePage);
}
}
document.Close();
现在，您可能会使用PdfCopy为要创建的新文档添加多个页面。注意：如果从未满足条件，则可以抛出异常。