我们有一个C＃应用程序，它将读取条形码的pdf文档，如果找到条形码，它会将文档上传到IBM FileNet P8中的文件。
如果未找到条形码，则会将其移至其他文件夹。
现在我们还有一个来自客户的请求。检查PDF是否为空白。从某种意义上说，如果用户扫描白页并通过电子邮件发送PDF。
如果是，请检查是否为空白。
我正在使用iTextSharp。
由于
答案 0 :(得分：0)
com.itextpdf.text.pdf.parser.PdfContentReaderTool
似乎这将返回'outp.WriteLine（“页面上没有找到文字”+ pageNum）;' 对于所有页面或0/1：）
我认为这可以帮助你......希望如此。
CODE
namespace iTextSharp.text.pdf.parser{
/**
* Tool that parses the content of a PDF document.
* @since 2.1.4
*/
public class PdfContentReaderTool {
/**
* Shows the detail of a dictionary.
* This is similar to the PdfLister functionality.
* @param dic the dictionary of which you want the detail
* @return a String representation of the dictionary
*/
public static String GetDictionaryDetail(PdfDictionary dic){
return GetDictionaryDetail(dic, 0);
}
/**
* Shows the detail of a dictionary.
* @param dic the dictionary of which you want the detail
* @param depth the depth of the current dictionary (for nested dictionaries)
* @return a String representation of the dictionary
*/
public static String GetDictionaryDetail(PdfDictionary dic, int depth){
StringBuilder builder = new StringBuilder();
builder.Append('(');
IList<PdfName> subDictionaries = new List<PdfName>();
foreach (PdfName key in dic.Keys) {
PdfObject val = dic.GetDirectObject(key);
if (val.IsDictionary())
subDictionaries.Add(key);
builder.Append(key);
builder.Append('=');
builder.Append(val);
builder.Append(", ");
}
builder.Length = builder.Length-2;
builder.Append(')');
foreach (PdfName pdfSubDictionaryName in subDictionaries) {
builder.Append('\n');
for (int i = 0; i < depth+1; i++){
builder.Append('\t');
}
builder.Append("Subdictionary ");
builder.Append(pdfSubDictionaryName);
builder.Append(" = ");
builder.Append(GetDictionaryDetail(dic.GetAsDict(pdfSubDictionaryName), depth+1));
}
return builder.ToString();
}
/**
* Displays a summary of the entries in the XObject dictionary for the stream
* @param resourceDic the resource dictionary for the stream
* @return a string with the summary of the entries
* @throws IOException
* @since 5.0.2
*/
public static String GetXObjectDetail(PdfDictionary resourceDic) {
StringBuilder sb = new StringBuilder();
PdfDictionary xobjects = resourceDic.GetAsDict(PdfName.XOBJECT);
if (xobjects == null)
return "No XObjects";
foreach (PdfName entryName in xobjects.Keys) {
PdfStream xobjectStream = xobjects.GetAsStream(entryName);
sb.Append("------ " + entryName + " - subtype = " + xobjectStream.Get(PdfName.SUBTYPE) + " = " + xobjectStream.GetAsNumber(PdfName.LENGTH) + " bytes ------\n");
if (!xobjectStream.Get(PdfName.SUBTYPE).Equals(PdfName.IMAGE)){
byte[] contentBytes = ContentByteUtils.GetContentBytesFromContentObject(xobjectStream);
foreach (byte b in contentBytes) {
sb.Append((char)b);
}
sb.Append("------ " + entryName + " - subtype = " + xobjectStream.Get(PdfName.SUBTYPE) + "End of Content" + "------\n");
}
}
return sb.ToString();
}
/**
* Writes information about a specific page from PdfReader to the specified output stream.
* @since 2.1.5
* @param reader the PdfReader to read the page content from
* @param pageNum the page number to read
* @param out the output stream to send the content to
* @throws IOException
*/
public static void ListContentStreamForPage(PdfReader reader, int pageNum, TextWriter outp) {
outp.WriteLine("==============Page " + pageNum + "====================");
outp.WriteLine("- - - - - Dictionary - - - - - -");
PdfDictionary pageDictionary = reader.GetPageN(pageNum);
outp.WriteLine(GetDictionaryDetail(pageDictionary));
outp.WriteLine("- - - - - XObject Summary - - - - - -");
outp.WriteLine(GetXObjectDetail(pageDictionary.GetAsDict(PdfName.RESOURCES)));
outp.WriteLine("- - - - - Content Stream - - - - - -");
RandomAccessFileOrArray f = reader.SafeFile;
byte[] contentBytes = reader.GetPageContent(pageNum, f);
f.Close();
outp.Flush();
foreach (byte b in contentBytes) {
outp.Write((char)b);
}
outp.Flush();
outp.WriteLine("- - - - - Text Extraction - - - - - -");
String extractedText = PdfTextExtractor.GetTextFromPage(reader, pageNum, new LocationTextExtractionStrategy());
if (extractedText.Length != 0)
outp.WriteLine(extractedText);
else
outp.WriteLine("No text found on page " + pageNum);
outp.WriteLine();
}
/**
* Writes information about each page in a PDF file to the specified output stream.
* @since 2.1.5
* @param pdfFile a File instance referring to a PDF file
* @param out the output stream to send the content to
* @throws IOException
*/
public static void ListContentStream(string pdfFile, TextWriter outp) {
PdfReader reader = new PdfReader(pdfFile);
int maxPageNum = reader.NumberOfPages;
for (int pageNum = 1; pageNum <= maxPageNum; pageNum++){
ListContentStreamForPage(reader, pageNum, outp);
}
}
/**
* Writes information about the specified page in a PDF file to the specified output stream.
* @since 2.1.5
* @param pdfFile a File instance referring to a PDF file
* @param pageNum the page number to read
* @param out the output stream to send the content to
* @throws IOException
*/
public static void ListContentStream(string pdfFile, int pageNum, TextWriter outp) {
PdfReader reader = new PdfReader(pdfFile);
ListContentStreamForPage(reader, pageNum, outp);
}
/**
* Writes information about each page in a PDF file to the specified file, or System.out.
* @param args
*/
public static void Main(String[] args) {
try{
if (args.Length < 1 || args.Length > 3){
Console.WriteLine("Usage: PdfContentReaderTool <pdf file> [<output file>|stdout] [<page num>]");
return;
}
TextWriter writer = Console.Out;
if (args.Length >= 2){
if (!Util.EqualsIgnoreCase(args[1], "stdout")) {
Console.WriteLine("Writing PDF content to " + args[1]);
writer = new StreamWriter(args[1]);
}
}
int pageNum = -1;
if (args.Length >= 3){
pageNum = int.Parse(args[2]);
}
if (pageNum == -1){
ListContentStream(args[0], writer);
} else {
ListContentStream(args[0], pageNum, writer);
}
writer.Flush();
if (args.Length >= 2){
writer.Close();
Console.WriteLine("Finished writing content to " + args[1]);
}
} catch (Exception e){
Console.WriteLine(e.ToString());
}
}
}
}
/CODE