Creating and updating Excel files with Clojure/poi.apache.org

excel_core.clj

((ns excel.core
  (:import [org.apache.poi.hssf.usermodel HSSFWorkbook HSSFSheet HSSFRow
            HSSFRichTextString HSSFFont HSSFDataFormat 
            HSSFCellStyle HSSFCell])
  (:import [java.io FileOutputStream FileInputStream IOException])
  #_(:import [org.apache.poi.ss.util CellRangeAdrress]))


(defn make-excel [file-name]
  (let [wb (HSSFWorkbook.)
        s (.createSheet wb)]
    (.setSheetName wb 0 "HSSF Test")
    (dorun (for [idx (range 100)]
      (let [row (.createRow s idx)]
        (dorun (for [col (range 100)]
           (let [c (.createCell row col)]
              (.setCellValue c (double (* idx col)))))))))
    (with-open [out (FileOutputStream. file-name)]
      (.write wb out))
       ))

(defn update-excel [file-name]
  (let [wb (HSSFWorkbook. (FileInputStream. file-name))
        s (.getSheetAt wb 0)
        last-row (.getLastRowNum s)
        row (.createRow s (inc last-row)) ; .getRow
        cell (.createCell row 0) ; .getCell
        date-style (doto (.createCellStyle wb)
                         (.setDataFormat (-> wb .getCreationHelper .createDataFormat (.getFormat "yyyy-m-d h:mm"))))]
     ;Java: date-style.setDataFormat(wb.getCreationHelper().createDataFormat().getFormat("yyyy-m-d h:mm"));
     (doto cell
        (.setCellStyle date-style)
        (.setCellValue (java.util.Date.)))
     (.setCellValue (.createCell row 1) "I was here")
    (with-open [out (FileOutputStream. file-name)]
        (.write wb out))))


(defn -main []
  (make-excel "testing.xls")
  (update-excel "update.xls")
  )

project.clj

(defproject excel "1.0.0-SNAPSHOT"
  :description "FIXME: write description"
  :dependencies [[org.clojure/clojure "1.2.1"]]
  ; you need poi-3.7-20101029.jar (1.5 MB) from the Apache poi project
  :main excel.core)

How do we read existing excel sheet!

(HSSFWorkbook. (FileInputStream. file-name))

is the key line for reading an existing file

When trying to load an Excel 5.0/7.0 sheet from an industrial pH sensor, I'm getting the following exception when calling (HSSFWorkbook. (FileInputStream. (str "/path/to/file.xls"))):

CompilerException org.apache.poi.hssf.OldExcelFormatException: The supplied spreadsheet seems to
be Excel 5.0/7.0 (BIFF5) format. POI only supports BIFF8 format (from Excel versions 97/2000/XP/2003), compiling`