今天在原來上傳文件頁面的基礎(chǔ)上,想添加一段文件的簡介
因為同時要上傳文件,所以ENCTYPE="multipart/form-data" 必須要加在form里面
可是這樣的話,我再Servlet里面用request.getParameter()方法無論如何都只是獲得null值,
不是一般的郁悶,百度了一下,有人出現(xiàn)了同樣的問題可是它用的是JSPsmartupload組件實現(xiàn)文件上傳的,
而我用的commons fileupload組件,仔細(xì)看了一下這個組件的api,可是英語太差了,沒有發(fā)現(xiàn)相關(guān)的信息
我又嘗試用session傳遞參數(shù),可是發(fā)現(xiàn)有點麻煩,因為在表單提交之時你就得賦給session表單上它的數(shù)值,
這似乎要JavaScript,可是偶也不會,
后來只有g(shù)oogle了,搜索了一些中文網(wǎng)頁,也沒有找到資料,試試不限制語言,呵呵呵,一大片,后來被俺發(fā)
現(xiàn)了這個
I cannot read the submitter using request.getParameter("submitter") (it returns null). ]
Situation:Javax.servlet.HttpServletRequest.getParameter(String) returns null when the ContentType is multipart/form-dataSolutions:Solution A:1. download http://www.servlets.com/cos/index.html2. invoke getParameters() on com.oreilly.servlet.MultipartRequestSolution B:1. download http://jakarta.apache.org/commons/sandbox/fileupload/2. invoke readHeaders() inorg.apache.commons.fileupload.MultipartStreamSolution C:1. download http://users.boone.net/wbrameld/multipartformdata/2. invoke getParameter oncom.bigfoot.bugar.servlet.http.MultipartFormDataSolution D:Use Struts. Struts 1.1 handles this automatically.
說是不詳細(xì),接著往下看,另一種解決方法
> Solution B:
> 1. download
> http://jakarta.apache.org/commons/sandbox/fileupload/
> 2. invoke readHeaders() in
> org.apache.commons.fileupload.MultipartStream
The Solution B as given by my dear friend is a bit hectic and a bit complex :(
We can try the following solution which I found much simpler (at least in usage).
1. Download one of the versions of UploadFile from http://jakarta.apache.org/commons/fileupload/
2. Invoke parseRequest(request) on org.apache.commons.fileupload.FileUploadBase which returns list of org.apache.commons.fileupload.FileItem objects.
3. Invoke isFormField() on each of the FileItem objects. This determines whether the file item is a form paramater or stream of uploaded file.
4. Invoke getFieldName() to get parameter name and getString() to get parameter value on FileItem if it's a form parameter. Invoke write(java.io.File) on FileItem to save the uploaded file stream to a file if the FileItem is not a form parameter.
按照上面的步驟來,果然一切都o(jì)k,GOOGLE真不錯,主要是getFieldName和getString,
雖然說這種做法有一點麻煩,但稍微判斷加工一下,總比獲取不到強