在beans文件中要加入
????<bean?id="multipartResolver"
??????????class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
??????????<description>
??????????????????ifpre::要使用文件上傳功能，必須在定義文件中加入MeltipartResolver,
??????????????????可以選用CommonsMutipartResolver或CosMultipartResolver
??????????</description>
????????<property?name="maxUploadSize">
????????????<value>1000000</value>
????????</property>
????</bean>

同時上傳文件使用到相依賴的Commands FileUpload，所以要在lib目錄中包括commons-fileupload.jar文件。

寫完后調試的過程中，老報錯：java.lang.NoClassDefFoundError: org/apache/commons/io/output/DeferredFileOutputStream，少了commons-io.jar，加上后，就ok了

在Controller端，可以用以下方式取得上傳的文件，可以上傳多個文件：
?public Set getMultipartFileForForm(HttpServletRequest req) {
??MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) req;
??// CommonsMultipartFile file = (CommonsMultipartFile)
??// multipartRequest.getFile("attach");//attach為form為file的id值
??// MultipartHttpServletRequest multipartRequest =
??// (MultipartHttpServletRequest)request;
??Set fileset = new LinkedHashSet();
??for (Iterator it = multipartRequest.getFileNames(); it.hasNext();) {
???String key = (String) it.next();
???MultipartFile file = multipartRequest.getFile(key);
???if (file.getOriginalFilename().length() > 0) {
????fileset.add(file);
???}
??}
??return fileset;
?}