如何解决iTextSharp Pdf页面导入内存问题
| 我正在使用此代码将不同的pdf文件页面导入单个文档。导入大文件（200页或以上）时，出现“ 0”例外。我在这里做错什么了吗？ private bool SaveToFile(string fileName)
{
try
{
iTextSharp.text.Document doc;
iTextSharp.text.pdf.PdfCopy pdfCpy;
string output = fileName;
doc = new iTextSharp.text.Document();
pdfCpy = new iTextSharp.text.pdf.PdfCopy(doc,new System.IO.FileStream(output,System.IO.FileMode.Create));
doc.Open();
foreach (DataGridViewRow item in dvSourcePreview.Rows)
{
string pdfFileName = item.Cells[COL_FILENAME].Value.ToString();
int pdfPageIndex = int.Parse(item.Cells[COL_PAGE_NO].Value.ToString());
pdfPageIndex += 1;
iTextSharp.text.pdf.PdfReader reader = new iTextSharp.text.pdf.PdfReader(pdfFileName);
int pageCount = reader.NumberOfPages;
// set page size for the documents
doc.SetPageSize(reader.GetPageSizeWithRotation(1));
iTextSharp.text.pdf.PdfImportedPage page = pdfCpy.GetImportedPage(reader,pdfPageIndex);
pdfCpy.AddPage(page);
reader.Close();
}
doc.Close();
return true;
}
catch (Exception ex)
{
return false;
}
}
解决方法
您正在为每个通行证创建一个新的
PdfReader
PdfImportedPage
PdfReader
PdfReader
PdfReader
freeReader()
using System;
using System.Windows.Forms;
using System.IO;
using iTextSharp.text;
using iTextSharp.text.pdf;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender,EventArgs e)
{
//Folder that we will be working in
string WorkingFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop),\"Big File PDF Test\");
//Base name of PDFs that we will be creating
string BigFileBase = Path.Combine(WorkingFolder,\"BigFile\");
//Final combined PDF name
string CombinedFile = Path.Combine(WorkingFolder,\"Combined.pdf\");
//Number of \"large\" files to create
int NumberOfBigFilesToMakes = 10;
//Number of pages to put in the files
int NumberOfPagesInBigFile = 1000;
//Number of pages to insert into combined file
int NumberOfPagesToInsertIntoCombinedFile = 500;
//Create our test directory
if (!Directory.Exists(WorkingFolder)) Directory.CreateDirectory(WorkingFolder);
//First step,create a bunch of files with a bunch of pages,hopefully code is self-explanatory
for (int FileCount = 1; FileCount <= NumberOfBigFilesToMakes; FileCount++)
{
using (FileStream FS = new FileStream(BigFileBase + FileCount + \".pdf\",FileMode.Create,FileAccess.Write,FileShare.Read))
{
using (iTextSharp.text.Document Doc = new iTextSharp.text.Document(PageSize.LETTER))
{
using (PdfWriter writer = PdfWriter.GetInstance(Doc,FS))
{
Doc.Open();
for (int I = 1; I <= NumberOfPagesInBigFile; I++)
{
Doc.NewPage();
Doc.Add(new Paragraph(\"This is file \" + FileCount));
Doc.Add(new Paragraph(\"This is page \" + I));
}
Doc.Close();
}
}
}
}
//Second step,loop around pulling random pages from random files
//Create our output file
using (FileStream FS = new FileStream(CombinedFile,FileShare.Read))
{
using (Document Doc = new Document())
{
using (PdfCopy pdfCopy = new PdfCopy(Doc,FS))
{
Doc.Open();
//Setup some variables to use in the loop below
PdfReader reader = null;
PdfImportedPage page = null;
int RanFileNum = 0;
int RanPageNum = 0;
//Standard random number generator
Random R = new Random();
for (int I = 1; I <= NumberOfPagesToInsertIntoCombinedFile; I++)
{
//Just to output our current progress
Console.WriteLine(I);
//Get a random page and file. Remember iText pages are 1-based.
RanFileNum = R.Next(1,NumberOfBigFilesToMakes + 1);
RanPageNum = R.Next(1,NumberOfPagesInBigFile + 1);
//Open the random file
reader = new PdfReader(BigFileBase + RanFileNum + \".pdf\");
//Set the current page
Doc.SetPageSize(reader.GetPageSizeWithRotation(1));
//Grab a random page
page = pdfCopy.GetImportedPage(reader,RanPageNum);
//Add it to the combined file
pdfCopy.AddPage(page);
//Clean up
reader.Close();
}
//Clean up
Doc.Close();
}
}
}
}
}
}
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