java 上传问题出现问题，上传的文件不大

java 上传问题出现问题，上传的文件不大，才几KB，（我是用来批量用户导入的），只要我在文件里写了很多的用户，就会报错，有时候写几个用户 也会出错，不是文件大小的问题，文件一直都很小 报错信息如下:希望高手指点一下
type Exception reportmessage description The server encountered an internal error () that prevented it from fulfilling this request.exception javax.servlet.ServletException: Processing of multipart/form-data request failed. Read timed out
org.apache.struts.upload.CommonsMultipartRequestHandler.handleRequest(CommonsMultipartRequestHandler.java:202)
org.apache.struts.util.RequestUtils.populate(RequestUtils.java:442)
org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.java:816)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:203)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
cn.com.enlink.common.PJActionServlet.process(PJActionServlet.java:435)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
com.enlink.webproxy.filtertest.doFilter(filtertest.java:45)
cn.com.enlink.common.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:35)
root cause org.apache.commons.fileupload.FileUploadException: Processing of multipart/form-data request failed. Read timed out
org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:429)
org.apache.struts.upload.CommonsMultipartRequestHandler.handleRequest(CommonsMultipartRequestHandler.java:193)
org.apache.struts.util.RequestUtils.populate(RequestUtils.java:442)
org.apache.struts.action.RequestProcessor.processPopulate(RequestProcessor.java:816)
org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:203)
org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
cn.com.enlink.common.PJActionServlet.process(PJActionServlet.java:435)
org.apache.struts.action.ActionServlet.doPost(ActionServlet.java:432)
javax.servlet.http.HttpServlet.service(HttpServlet.java:709)
javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
com.enlink.webproxy.filtertest.doFilter(filtertest.java:45)
cn.com.enlink.common.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:35)
note The full stack trace of the root cause is available in the Apache Tomcat/5.0.28 logs.