Common-fileUpload上传文件异常问题

现在在使用Struts2+ swfUpload+ Common-FileUpload做文件上传,上传文件过程中如果取消了文件上传，后台就抛出以下异常,请大家帮忙看看？
抛出的异常:
org.apache.commons.fileupload.FileUploadBase$IOFileUploadException: Processing of multipart/form-data request failed. Stream ended unexpectedly
at org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:367)
at org.apache.struts2.dispatcher.multipart.JakartaMultiPartRequest.parse(JakartaMultiPartRequest.java:93)
at org.apache.struts2.dispatcher.multipart.MultiPartRequestWrapper.<init>(MultiPartRequestWrapper.java:75)
at org.apache.struts2.dispatcher.Dispatcher.wrapRequest(Dispatcher.java:708)
at org.apache.struts2.dispatcher.ng.PrepareOperations.wrapRequest(PrepareOperations.java:131)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:83)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:879)
at org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:617)
at org.apache.tomcat.util.net.AprEndpoint$Worker.run(AprEndpoint.java:1760)
at java.lang.Thread.run(Thread.java:619)
后台文件上传Action类如下：public class FileUploadAction extends ActionSupport {
/**
 * 
 */
private static final long serialVersionUID = 2660658197476593891L;
private File file;             //该File 要与swfUpload中的 file_post_name值相同
private String fileFileName;
private String fileContentType;
private String name; @SuppressWarnings("deprecation")
public String execute() throws Exception {
// 实现上传
InputStream is = new FileInputStream(file);
String root = ServletActionContext.getServletContext().getRealPath("/upload");

System.out.println("**Path : "+root+this.getFileFileName());

File deskFile = new File(root, this.getFileFileName());

OutputStream os = new FileOutputStream(deskFile);

byte[] bytefer = new byte[1024];
int length = 0;
while ((length = is.read(bytefer)) != -1) 
{
os.write(bytefer, 0, length);
}
os.close();
is.close();
return "success";
} //set,get方法略..
大家帮忙看看，有没有碰到过的..异常