合并PDF的方法

import  java.io.FileOutputStream;   import  java.io.IOException;   import  java.util.ArrayList;      import  com.lowagie.text.Document;   import  com.lowagie.text.DocumentException;   import  com.lowagie.text.pdf.PdfCopy;   import  com.lowagie.text.pdf.PdfImportedPage;   import  com.lowagie.text.pdf.PdfReader;         public  class  pdfOperate    {       private  static  final  int  N = 3 ;              public  static  void  main(String[] args)       {           String[] files = {"C://a.pdf" , "C://b.pdf" };           String savepath = "C://temp.pdf" ;           mergePdfFiles(files, savepath);                      partitionPdfFile("C://a.pdf" );       }              public  static  void  mergePdfFiles(String[] files, String savepath)       {           try             {               Document document = new  Document(new  PdfReader(files[0 ]).getPageSize(1 ));                              PdfCopy copy = new  PdfCopy(document, new  FileOutputStream(savepath));                              document.open();                              for (int  i=0 ; i<files.length; i++)               {                   PdfReader reader = new  PdfReader(files[i]);                                      int  n = reader.getNumberOfPages();                      for (int  j=1 ; j<=n; j++)                   {                       document.newPage();                        PdfImportedPage page = copy.getImportedPage(reader, j);                       copy.addPage(page);                   }               }                              document.close();              } catch  (IOException e) {               e.printStackTrace();           } catch (DocumentException e) {               e.printStackTrace();           }       }          public  static  void  partitionPdfFile(String filepath)       {           Document document = null ;           PdfCopy copy = null ;                      try             {               PdfReader reader = new  PdfReader(filepath);                              int  n = reader.getNumberOfPages();                              if (n < N)               {                   System.out.println("The document does not have "  + N + " pages to partition !" );                   return ;               }                              int  size = n/N;                        String staticpath = filepath.substring(0 , filepath.lastIndexOf("//" )+1 );                           String savepath = null ;               ArrayList<String> savepaths = new  ArrayList<String>();               for (int  i=1 ; i<=N; i++)               {                   if (i < 10 )                   {                       savepath = filepath.substring(filepath.lastIndexOf("//" )+1 , filepath.length()-4 );                       savepath = staticpath + savepath + "0"  + i + ".pdf" ;                       savepaths.add(savepath);                                       }                   else                    {                       savepath = filepath.substring(filepath.lastIndexOf("//" )+1 , filepath.length()-4 );                       savepath = staticpath + savepath + i + ".pdf" ;                       savepaths.add(savepath);                   }               }                                         for (int  i=0 ; i<N-1 ; i++)               {                   document = new  Document(reader.getPageSize(1 ));                   copy = new  PdfCopy(document, new  FileOutputStream(savepaths.get(i)));                              document.open();                   for (int  j=size*i+1 ; j<=size*(i+1 ); j++)                   {                       document.newPage();                        PdfImportedPage page = copy.getImportedPage(reader, j);                       copy.addPage(page);                   }                   document.close();               }                                             document = new  Document(reader.getPageSize(1 ));               copy = new  PdfCopy(document, new  FileOutputStream(savepaths.get(N-1 )));               document.open();               for (int  j=size*(N-1 )+1 ; j<=n; j++)               {                   document.newPage();                    PdfImportedPage page = copy.getImportedPage(reader, j);                   copy.addPage(page);               }               document.close();              } catch  (IOException e) {               e.printStackTrace();           } catch (DocumentException e) {               e.printStackTrace();           }       }   }