前端

 <div style="border:2px solid red" >
         		<img alt="证件" src="${base}/zjinfo/profile/avatar">
           </div>
            <form action="${base}/zjinfo/profile/avatar" method="post" enctype="multipart/form-data">
                 <input type="file" name="file">
                <button type="submit">更新</button>
            </form>

后端

public Object readAvatar(@Attr(scope=Scope.SESSION, value="me")String cxqqdh, HttpServletRequest req) throws SQLException {
    	System.out.println("cxqqdh:"+cxqqdh);
//    	OutputStream out = resp.getOutputStream();
    	Zjinfo zjinfo = Daos.ext(dao, FieldFilter.create(Zjinfo.class, "^gzz$")).fetch(Zjinfo.class, Cnd.where("cxqqdh", "=", cxqqdh).and("xh", "=", "1"));
//    	BufferedImage img = Images.read(new ByteArrayInputStream(buf));
    	byte[] b1 = null;
        if (zjinfo == null || zjinfo.getGzz()== null) {
            return new File(req.getServletContext().getRealPath(""));
        }
        
        return new File("C:\\Users\\15522\\Desktop\\sjw\\none.jpg");
    }