今天在原來(lái)上傳文件頁(yè)面的基礎(chǔ)上，想添加一段文件的簡(jiǎn)介

因?yàn)橥瑫r(shí)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(wú)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(wèn)題可是它用的是jspsmartupload組件實(shí)現(xiàn)文件上傳的，

而我用的commons fileupload組件，仔細(xì)看了一下這個(gè)組件的api，可是英語(yǔ)太差了，沒(méi)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(diǎn)麻煩，因?yàn)樵诒韱翁峤恢畷r(shí)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(huì)，

后來(lái)只有g(shù)oogle了，搜索了一些中文網(wǎng)頁(yè)，也沒(méi)有找到資料，試試不限制語(yǔ)言，呵呵呵，一大片，后來(lái)被俺發(fā)

現(xiàn)了這個(gè)

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-data

Solutions:

Solution A:

1. download http://www.servlets.com/cos/index.html
2. invoke getParameters() on com.oreilly.servlet.MultipartRequest

Solution B:

1. download http://jakarta.apache.org/commons/sandbox/fileupload/
2. invoke readHeaders() in 
org.apache.commons.fileupload.MultipartStream

Solution C:

1. download http://users.boone.net/wbrameld/multipartformdata/
2. invoke getParameter on 
com.bigfoot.bugar.servlet.http.MultipartFormData

Solution D:

Use Struts. Struts 1.1 handles this automatically.

說(shuō)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(lái)，果然一切都o(jì)k，ＧＯＯＧＬＥ真不錯(cuò)，主要是getFieldName和getString，

雖然說(shuō)這種做法有一點(diǎn)麻煩，但稍微判斷加工一下，總比獲取不到強(qiáng)