JSP上傳文件Java.lang.NullPointer

Question

我想開發從服務器上傳和下載文件。

Upload.html

<form action="/UploadFile/UploadFile" method="POST" 
enctype="multipart/form-data">Select a file: <input 
type="submit" name="button" /> <input type="file" name="first"></form> 

UploadFile.servlet

protected void doPost(HttpServletRequest request, 
     HttpServletResponse response) throws ServletException, IOException { 
    String temp = request.getParameter("first"); 
    System.out.println(temp); 
    File origFile = new File(temp); 
    FileOutputStream out = new FileOutputStream(request.getContextPath() 
      + "pdtImages/" + "FirstFile"); 
    InputStream ins = new FileInputStream(origFile); 
    try { 
     System.out.println(request.getContextPath()); 
     byte[] buf = new byte[1024]; 
     int len; 
     while ((len = ins.read(buf)) > 0) { 
      out.write(buf, 0, len); 
     } 
     out.close(); 
    } catch (FileNotFoundException e) { 
     e.printStackTrace(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 

} 

當我提交的文件我得到空指針錯誤信息。我不是很熟悉jsp有人能幫我嗎？我想將文件存儲到服務器目錄。

Answer 1

我使用Apache commons fileupload來執行此任務。