java html 多部分表单中输入文本字段的值

values of input text fields in a html multipart form

提问by aurel

I use Apache Commons FileUpload in a java server-side app that has a html form with fields :

我在 Java 服务器端应用程序中使用 Apache Commons FileUpload，该应用程序具有带有字段的 html 表单：

1. a destination fied that will be filled with email address of the destination mailbox

2. a message text with a message of the sender

3. a <input type=file ...field for uploading a photo. I can receive uploaded file (as a stream) but how I can access 1) and 2) form values (completed by the user of app)? Many thanks, Aurel

1. 一个目标字段，将填充目标邮箱的电子邮件地址

2. 带有发件人消息的消息文本

3. <input type=file ...用于上传照片的字段。我可以接收上传的文件（作为流），但如何访问 1）和 2）表单值（由应用程序用户完成）？非常感谢，奥雷尔

回答by pierrovic

I am guessing you are using a FileItemIterator to iterate the items in the request. The iterators next() method returns a FileItemStream (not a FileItem). Open the stream on that object and turn it into a string like this:

我猜您正在使用 FileItemIterator 来迭代请求中的项目。迭代器 next() 方法返回一个 FileItemStream（不是 FileItem）。打开该对象上的流并将其转换为这样的字符串：

import org.apache.commons.fileupload.util.Streams;
...
FileItemStream item = iterator.next();
InputStream stream = item.openStream();
String name = item.getFieldName();
String value = Streams.asString(stream);

The getString method suggested by other answers is a method on the FileItem interface.

其他答案建议的 getString 方法是 FileItem 接口上的一个方法。

回答by BalusC

You can receive them using the same API. Just hook on when FileItem#isFormField()returns true. If it returns falsethen it's an uploaded file as you probably already are using.

您可以使用相同的 API 接收它们。FileItem#isFormField()返回时挂上即可true。如果它返回，false那么它是一个上传的文件，因为您可能已经在使用。

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    try {
        List<FileItem> items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(request);
        for (FileItem item : items) {
            if (item.isFormField()) {
                // Process regular form field (input type="text|radio|checkbox|etc", select, etc).
                String fieldname = item.getFieldName();
                String fieldvalue = item.getString();
                // ... (do your job here)
            } else {
                // Process form file field (input type="file").
                String fieldname = item.getFieldName();
                String filename = FilenameUtils.getName(item.getName());
                InputStream filecontent = item.getInputStream();
                // ... (do your job here)
            }
        }
    } catch (FileUploadException e) {
        throw new ServletException("Cannot parse multipart request.", e);
    }

    // ...
}

回答by Ibolit

Here's what I am using for this purpose:

这是我为此目的使用的内容：

    public static Hashtable getParamsFromMultipartForm(HttpServletRequest req) throws FileUploadException {
        Hashtable ret = new Hashtable();
        List items = new ServletFileUpload(new DiskFileItemFactory()).parseRequest(req);
        for (FileItem item : items) {
            if (item.isFormField()) {
                ret.put(item.getFieldName(), item.getString());
            }
        }
        return ret;
    }

And then, whenever i need the value of any of my params, i just write, say:

然后，每当我需要我的任何参数的值时，我就写，说：

//at the beginning of a servlet
Hashtable multipartParams = TheClassWhereIPutThatMethod.getParamsFromMultipartForm(req);


String myParamFromForm = multipartParams.get("myParamFromForm");

回答by Yash Bansal

So, what I did is to use the instance of fileItem as in:

所以，我所做的是使用 fileItem 的实例，如下所示：

Hashtable incoming = new Hashtable();
fileName = sfu.parseRequest(request);

//iterating over each uploaded file and storing the values of different parameters in the HashTable (incoming)

for(FileItem f:fileName)
                    {
                    incoming.put(f.getFieldName(), f.getString()); 
                    }
//utilizing that HashTable and getting the value of desired field in the below manner, as in my case i required the value of "permissions" from the jsp page

             for(FileItem f:fileName)
                    {
                        String role= (String)incoming.get("permission"); //as it is a multipart form request, so need to get using this
                    }   

Thanks

谢谢