关于simditor上传图片的问题

<script type="text/javascript">
   $(function(){
    toolbar = [ 'title', 'bold', 'italic', 'underline', 'strikethrough',
            'color', '|', 'ol', 'ul', 'blockquote', 'code', 'table', '|',
            'link', 'image', 'hr', '|', 'indent', 'outdent' ];
    var editor = new Simditor( {
        textarea : $('#editor'),
        placeholder : '这里输入内容...',
        toolbar : toolbar,  //工具栏
        defaultImage : 'simditor-2.0.1/images/image.png', //编辑器插入图片时使用的默认图片
        upload : {
            url : 'ImgUpload.action', //文件上传的接口地址
            params: null, //键值对,指定文件上传接口的额外参数,上传的时候随文件一起提交
            fileKey: 'fileDataFileName', //服务器端获取文件数据的参数名
            connectionCount: 3,
            leaveConfirm: '正在上传文件'
        } 
    });
   })
</script>

return _this.input = $('<input name="fileData" type="file" title="' + Simditor._t('uploadImage') 
+ '" accept="image/*">').appendTo($uploadBtn);

public class ImgUploadAction extends ActionSupport {  
    private static final long serialVersionUID = 1L;
    private String err = "";  
    private String msg;              //返回信息  
    private File fileData;           //上传文件  
    private String fileDataFileName; //文件名  
  
    public String imgUpload() {  
        //获取response、request对象  
        ActionContext ac = ActionContext.getContext();  
        HttpServletResponse response = (HttpServletResponse) ac.get(ServletActionContext.HTTP_RESPONSE);  
        HttpServletRequest request = (HttpServletRequest) ac.get(ServletActionContext.HTTP_REQUEST);  
          
        response.setContentType("text/html;charset=gbk");  
          
        PrintWriter out = null;  
        try {  
            out = response.getWriter();  
        } catch (IOException e1) {  
            e1.printStackTrace();  
        }  
  
        String saveRealFilePath = ServletActionContext.getServletContext().getRealPath("/upload");  
        File fileDir = new File(saveRealFilePath);  
        if (!fileDir.exists()) { //如果不存在 则创建   
            fileDir.mkdirs();  
        }  
        File savefile;  
        savefile = new File(saveRealFilePath + "/" + fileDataFileName); 
        try {  
            FileUtils.copyFile(fileData, savefile);  
        } catch (IOException e) {  
            err = "错误"+e.getMessage();  
            e.printStackTrace();  
        }  
        String file_Name = request.getContextPath() + "/upload/" + fileDataFileName;  
        
        msg = "{\"success\":\"" + true + "\",\"file_path\":\"" + file_Name + "\"}";  
        out.print(msg); //返回msg信息  
        return null;  
    }  
  
    public String getErr() {  
        return err;  
    }  
    public void setErr(String err) {  
        this.err = err;  
    }  
    
    public String getMsg() {  
        return msg;  
    }  
    public void setMsg(String msg) {  
        this.msg = msg;  
    }
    
    public File getFileData() {
        return fileData;
    }
    public void setFileData(File fileData) {
        this.fileData = fileData;
    }
    
    public String getFileDataFileName() {
        return fileDataFileName;
    }
    public void setFileDataFileName(String fileDataFileName) {
        this.fileDataFileName = fileDataFileName;
    }  
}