的Apache POI拋出IOException異常時閱讀XLSX工作簿

Question

我試圖讓下面的代碼運行，並正在一個IOException：

String cellText = null; 
InputStream is = null; 
try { 
    // Find /mydata/myworkbook.xlsx 
    is = new FileInputStream("/mydata/myworkbook.xlsx"); 
    is.close(); 

    System.out.println("Found the file!"); 

    // Read it in as a workbook and then obtain the "widgets" sheet. 
    Workbook wb = new XSSFWorkbook(is); 
    Sheet sheet = wb.getSheet("widgets"); 

    System.out.println("Obtained the widgets sheet!"); 

    // Grab the 2nd row in the sheet (that contains the data we want). 
    Row row = sheet.getRow(1); 

    // Grab the 7th cell/col in the row (containing the Plot 500 English Description). 
    Cell cell = row.getCell(6); 
    cellText = cell.getStringCellValue(); 

    System.out.println("Cell text is: " + cellText); 
} catch(Throwable throwable) { 
    System.err.println(throwable.getMessage()); 
} finally { 
    if(is != null) { 
     try { 
      is.close(); 
     } catch(IOException ioexc) { 
      ioexc.printStackTrace(); 
     } 
    } 
} 

在Eclipse中運行這個輸出：

Found the file! 
Stream Closed 
java.io.IOException: Stream Closed 
    at java.io.FileInputStream.readBytes(Native Method) 
    at java.io.FileInputStream.read(FileInputStream.java:236) 
    at java.io.FilterInputStream.read(FilterInputStream.java:133) 
    at java.io.PushbackInputStream.read(PushbackInputStream.java:186) 
    at java.util.zip.ZipInputStream.readFully(ZipInputStream.java:414) 
    at java.util.zip.ZipInputStream.readLOC(ZipInputStream.java:247) 
    at java.util.zip.ZipInputStream.getNextEntry(ZipInputStream.java:91) 
    at org.apache.poi.openxml4j.util.ZipInputStreamZipEntrySource.<init>(ZipInputStreamZipEntrySource.java:51) 
    at org.apache.poi.openxml4j.opc.ZipPackage.<init>(ZipPackage.java:83) 
    at org.apache.poi.openxml4j.opc.OPCPackage.open(OPCPackage.java:267) 
    at org.apache.poi.util.PackageHelper.open(PackageHelper.java:39) 
    at org.apache.poi.xssf.usermodel.XSSFWorkbook.<init>(XSSFWorkbook.java:204) 
    at me.myorg.MyAppRunner.run(MyAppRunner.java:39) 
    at me.myorg.MyAppRunner.main(MyAppRunner.java:25) 

異常來自行：

Workbook wb = new XSSFWorkbook(is); 

根據XSSFWorkbook Java Docs這是一個XSSFWorkbook對象的有效構造函數，我沒有看到任何「跳出來」的對象，表示我錯誤地使用了我的InputStream。任何POI大師能幫我找出我要去哪裏？提前致謝。

Answer 1

的問題很簡單：

is = new FileInputStream("/mydata/myworkbook.xlsx"); 
is.close(); 

你將它傳遞給構造函數之前關閉您的輸出流，它不能被讀取。

只需在此處刪除is.close（）即可解決問題，因爲它將在finally語句中清除。

Answer 2

你關閉流is.close();

，然後用它，不要關閉它，直到你使用它。

Answer 3

正如其他人指出的那樣，你是關閉您的InputStream這破事

但是，你真的不應該使用的InputStream擺在首位！ POI uses less memory when given the File object directly而不是通過InputStream。

我建議你讀通過POI FAQ on File vs InputStream，然後改變你的代碼：

OPCPackage pkg = OPCPackage.open(new File("/mydata/myworkbook.xlsx")); 
Workbook wb = new XSSFWorkbook(pkg);