2

我正在尝试通过翻译我在此处找到的 splitPDF 方法使用 clojure 从 pdf 中提取单个页面http://viralpatel.net/blogs/itext-tutorial-merge-split-pdf-files-using-itext-jar/

我不断收到此错误

IOException 流关闭 java.io.FileOutputStream.writeBytes (:-2)

这可以防止我在 repl 仍然打开时打开文档。关闭 repl 后,我就可以访问该文档。

为什么我会收到错误消息?

我如何解决它 ?

我怎样才能使它更clojurey?

(import '(com.itextpdf.text Document)
            '(com.itextpdf.text.pdf PdfReader PdfWriter PdfContentByte PdfImportedPage BaseFont)
            '(java.io File FileInputStream FileOutputStream InputStream OutputStream))

(defn extract-page [src dest pagenum]
  (with-open  [ d (Document.) 
                os (FileOutputStream. dest)]
    (let [ srcpdf (->> src FileInputStream. PdfReader.)
           destpdf  (PdfWriter/getInstance d os)]
         (doto d
            (.open )
            (.newPage ))
          (.addTemplate 
                (.getDirectContent destpdf)
                (.getImportedPage destpdf srcpdf pagenum) 0 0))))
4

1 回答 1

3

您忘记关闭文档:

(close. d)

以下代码有效:

(import '(com.itextpdf.text Document)
            '(com.itextpdf.text.pdf PdfReader PdfWriter PdfContentByte PdfImportedPage BaseFont)
            '(java.io File FileInputStream FileOutputStream InputStream OutputStream))

(defn extract-page [src dest pagenum]
  (with-open  [ is (FileInputStream. src)
                os (FileOutputStream. dest)]
    (let [ srcpdf (PdfReader. src)
           d (Document.)
           destpdf  (PdfWriter/getInstance d os)]
         (doto d
            (.open )
            (.newPage ))
         (println "Number of pages" (.getNumberOfPages srcpdf))
         (.addTemplate 
                (.getDirectContent destpdf)
                (.getImportedPage destpdf srcpdf pagenum) 0 0)
         (.close d))))

编辑:

如果您有兴趣,我发现使用 apache pdfbox 更容易。

(import '(org.apache.pdfbox.pdmodel PDDocument)
        '(org.apache.pdfbox.util PDFTextStripper)
        '(java.io File OutputStreamWriter FileOutputStream BufferedWriter))

(defn convert-to-text [src dest]
  (with-open [ pd (PDDocument/load (File. src))
               wr (BufferedWriter. (OutputStreamWriter. (FileOutputStream. (File. dest))))]
    (let [ stripper (PDFTextStripper.)]
      (println "Number of pages" (.getNumberOfPages pd))
      (.writeText stripper pd wr))))
于 2012-08-28T09:37:17.630 回答