如何使用multipart/form-data從請求中獲取字符串參數？

我使html頁面上傳圖像與文字框有它的描述。我已經使用multipart/form-data;在servlet的dopost我得到的文件使用 ServletFileUpload upload = new ServletFileUpload（）;如何使用multipart/form-data從請求中獲取字符串參數？

獲取字符串參數我使用request.getparameter（）; 但它總是給我NULL？你能告訴我嗎？

HTML ::

<form name="filesForm" action="/upload" method="post" enctype="multipart/form-data"> 

File : <input type="file" name="file"> 
<textarea name = "description" 
rows = "4" cols = "30">Enter comments here.</textarea> 
<input type="submit" name="Submit" value="Upload File">

在servlet的：

ServletFileUpload upload = new ServletFileUpload(); 
upload.setSizeMax(500000000); 
FileItemIterator iterator = null; 
    try { 
     iterator = upload.getItemIterator(req); 
    } catch (FileUploadException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } // to handle contents or 
    // instances of request. 
    FileItemStream item = null; 
    try { 
     item = iterator.next(); 
    } catch (FileUploadException e) { 
     // TODO Auto-generated catch block 
     e.printStackTrace(); 
    } // get access each item on iterator. 
    java.io.InputStream in = item.openStream(); // allows to read the items contents. 


    Blob imageBlob = new Blob(IOUtils.toByteArray(in)); // store each item on Blob 


    // object after converting them to Bytes. 
    /*………. 
    Note: we are concerned on uploading images files. So the type of files is either (.jpg or gif) 
    ………. 
    */ 
    PersistenceManager pm = PMF.get().getPersistenceManager(); 
    String counter="1"; 
    ServletOutputStream outt = resp.getOutputStream(); 
    //match incoming request Content type and invoke appropriate method for handel request

來源

2012-04-30 Hanaa

它，因爲當你有形式enctype="multipart/form-data"。您無法使用request.getParameter("paramnName");獲得其他表單域。它會一直給你NULL。

您必須使用FormItem的isFormField()來檢查其常規字段或文件。

例子：

 try { 
      ServletFileUpload upload = new ServletFileUpload(); 
      response.setContentType("text/plain"); 

      FileItemIterator iterator = upload.getItemIterator(request); 

      while (iterator.hasNext()) { 
       FileItemStream item = iterator.next(); 

       InputStream stream = item.openStream(); 

       if (item.isFormField()) { 
        System.out.println("Got a form field: " + item.getFieldName() + " " +item); 

       } else{ 
        System.out.println("Got an uploaded file: " + item.getFieldName() + 
          ", name = " + item.getName()); 
       int len; 
       byte[] buffer = new byte[8192]; 
       while ((len = stream.read(buffer, 0, buffer.length)) != -1) { 

        response.getOutputStream().write(buffer, 0, len); 

       } 

      } 

     } 
} catch (FileUploadException e) { 
    // TODO Auto-generated catch block 
    e.printStackTrace(); 
}

來源

2012-04-30 06:18:13

怎麼樣？ ??你可以給我一個例子嗎？？？ – Hanaa

你檢查了鏈接嗎？ –

我嘗試過，但現在它給我例外 – Hanaa

添加到答案和解決問題@Sayo Oladeji

爲了得到一個輸入字段的值，你可以使用以下命令：

System.out.println("Got a form field: " + item.getFieldName() + " " + Streams.asString(stream));

來源

2015-08-14 02:27:30 CYMA

如何使用multipart/form-data從請求中獲取字符串參數？

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