如果不知道MultipartResolver 或者ServletFileUpload 的,请点击这里
如果同时使用了MultipartResolver 和ServletFileUpload,就会在iter.hasNext()返回false.然后整个循环就跳出去了。
if (isMultipart) { DiskFileItemFactory factory = new DiskFileItemFactory(1024 * 1024 * 20, null); ServletFileUpload upload = new ServletFileUpload(factory); upload.setHeaderEncoding("UTF-8"); upload.setSizeMax(1024 * 1024 * 20); List<FileItem> fileItems = upload.parseRequest(req); Iterator<FileItem> iter = fileItems.iterator();
// 这里获取不到任何FileItem while (iter.hasNext()) { FileItem item = (FileItem) iter.next(); if (item.isFormField()) { String name = item.getFieldName(); String value = item.getString("UTF-8"); request.put(name, value); } else { byte[] filebytes = item.get(); if (StringUtils.isBlank(item.getName())) { continue; } request.put(item.getFieldName(), new String(filebyte, "utf-8")); } } } }
整个问题产生的原因是Spring框架先调用了MultipartResolver 来处理http multi-part的请求。这里http multipart的请求已经消耗掉。后面又交给ServletFileUpload ,那么ServletFileUpload 就获取不到相应的multi-part请求。
如果帐前 卒想快速解决这个问题。解决方法是加入帐前卒的multipartResolver,来单独处理某些请求。这些请求需要特判。例如下面的代码:
package example; import javax.servlet.http.HttpServletRequest; import org.springframework.web.multipart.commons.CommonsMultipartResolver; /** * @author 帐前卒 */ public class MyMultipartResolver extends CommonsMultipartResolver { private String excludeUrls; private String[] excludeUrlArray; public String getExcludeUrls() { return excludeUrls; } public void setExcludeUrls(String excludeUrls) { this.excludeUrls = excludeUrls; this.excludeUrlArray = excludeUrls.split(","); } /** * 这里是处理Multipart http的方法。如果这个返回值为true,那么Multipart http body就会MyMultipartResolver 消耗掉.如果这里返回false * 那么就会交给后面的自己写的处理函数处理例如刚才ServletFileUpload 所在的函数 * @see org.springframework.web.multipart.commons.CommonsMultipartResolver#isMultipart(javax.servlet.http.HttpServletRequest) */ @Override public boolean isMultipart(HttpServletRequest request) { for (String url: excludeUrlArray) {
// 这里可以自己换判断 if (request.getRequestURI().contains(url)) { return false; } } return super.isMultipart(request); } }
然后在web.xml中这样写:
<bean id="multipartResolver" class="example.MyMultipartResolver"> <property name="excludeUrls" value="example"/> <!-- url中带有example的http请求就不会被multipartResolver先解析--> </bean>