String savepath = ServletActionContext.getServletContext().getRealPath("/upload");System.out.println(savepath);    try {    File desc = new File(savepath,picFileName);    //FileUtils.copyFile(pic, desc);  《--采用此種方法以下均可省略，較簡單    InputStream is = new FileInputStream(pic);    OutputStream s = new FileOutputStream(desc);    byte[] buf = new byte[1024];    int len;    while((len=is.read(buf))!=-1){        os.write(buf);    }    is.close();    os.close();    } catch (Exception e) {        e.printStackTrace();    }

    易錯點：若寫成--》is.read(buf)<0 將無法讀取過來， 但是會在目標路徑生成一個零字節文件！