struts2处理上传的文件

public abstract class ActionEngine extends ActionSupport implements ServletRequestAware
{
    private HttpServletRequest httpServletRequest;
    public void setServletRequest(HttpServletRequest servletRequest)
    {
        this.httpServletRequest = servletRequest;
    }
    protected Map<String, Object> fileMap = new HashMap<String, Object>();
    public void preExecute() throws Exception
    {
        if (httpServletRequest instanceof MultiPartRequestWrapper)
        {
            MultiPartRequestWrapper requestWrapper = (MultiPartRequestWrapper) httpServletRequest;

            if (requestWrapper.hasErrors())
            {
                Collection<String> errors = requestWrapper.getErrors();
                if (errors != null && !errors.isEmpty())
                {
                    Iterator iterator = errors.iterator();
                    long maxSize = 0;
                    if (requestWrapper.getAttribute("maxSize") != null)
                    {
                        maxSize = Long.parseLong(requestWrapper.getAttribute("maxSize")
                                .toString());
                        maxSize = maxSize / 1024 / 1024;
                    }

                    while (iterator.hasNext())
                    {
                        throw new XXXException;
                    }
                }
                return;
            }

            Enumeration<String> parameterNames = requestWrapper.getFileParameterNames();
            while (parameterNames.hasMoreElements())
            {
                @SuppressWarnings("unused")
                String paramterName = parameterNames.nextElement();
                File[] files = requestWrapper.getFiles(paramterName);
                if (null == files || files.length == 0)
                {
                    continue;
                }
                else if (files.length == 1)
                {
                    FileBean fileBean = new FileBean();
                    fileBean.setAbsolutePath(files[0].getAbsolutePath());
                    fileBean.setFileSize(files[0].length());
                    fileBean.setFilename(requestWrapper.getFileNames(paramterName)[0]);
                    this.fileMap.put(paramterName, fileBean);
                }
                else
                {
                    ArrayList<FileBean> list = new ArrayList();
                    for (int i = 0; i < files.length; i++)
                    {
                        File file = files[i];
                        FileBean fileBean = new FileBean();
                        fileBean.setAbsolutePath(file.getAbsolutePath());
                        fileBean.setFileSize(file.length());
                        fileBean.setFilename(requestWrapper.getFileNames(paramterName)[i]);
                        list.add(fileBean);
                    }
                    this.fileMap.put(paramterName, list);
                }
            }
        }
    }
}