private File doc;
    private String docContentType;
    private String docFileName;
    private String path;
    
    public String execute() throws Exception{
        docFileName=getFileName(docFileName);
        System.out.println(docFileName);
        FileOutputStream fos = new FileOutputStream(getPath()+"\\"+docFileName);
        //FileOutputStream fos = new FileOutputStream(ServletActionContext.getServletContext().getRealPath(getPath())+"\\"+docFileName);
        FileInputStream fis=new FileInputStream(doc);
        byte[] b=new byte[1024];
        int length=0;
        while((length=fis.read(b))>0){
            fos.write(b,0,length);
        }  
        return SUCCESS;
    }
    public String getFileName(String fileName){
        int position = fileName.lastIndexOf(".");
        String extension=fileName.substring(position);
        return System.currentTimeMillis()+extension;
    }

    <action name="myUpload" class="action.MyUpload">
        <param name="path">/upload</param>
        <result name="success">/fileupload/uploadSuccess.jsp</result>
        <result name="input">/fileupload/upload.jsp</result>
        </action>