Java 按页拆分pdf

 public static void partitionPdfFile(String pdfFile,  
            String newFile, int from, int end) {  
        Document document = null;  
        PdfCopy copy = null;          
        try {  
            PdfReader reader = new PdfReader(pdfFile);            
            int n = reader.getNumberOfPages();            
            if(end==0){  
                end = n;  
            }  
            ArrayList<String> savepaths = new ArrayList<String>();  
            String staticpath = pdfFile.substring(0, pdfFile.lastIndexOf("\")+1);  
            String savepath = staticpath+ newFile;  
            savepaths.add(savepath);  
            document = new Document(reader.getPageSize(1));  
            copy = new PdfCopy(document, new FileOutputStream(savepaths.get(0)));  
            document.open();  
            for(int j=from; j<=end; j++) {
                document.newPage();
                PdfImportedPage page = copy.getImportedPage(reader, j);
                copy.addPage(page);
            }
            document.close();