表单提交后打印后台传过来的数据

页面

<div>
    <form action="uploadDocument" method="post" enctype="multipart/form-data" target= "hframe">
    <input type="file" name="file" id="exampleInputFile1" value="浏览" />
    <input type="text"    placeholder="请输入该图片的url"/>
    <input type="submit"   value="上传"  style=" 80px;"/>
    <iframe name ="hframe" id="hframe" style=" display: none" ></iframe >
    </form>
    </div>
    <script type="text/javascript">
        function callback(c){
            alert(c);
        }
    </script>

后台

public void uploadDocument(){
    HttpServletResponse response = ServletActionContext.getResponse();
    response.setContentType("text/html;charset=utf-8");
    PrintWriter out=null;
    try {
        out=response.getWriter();
        out.write("<script type='text/javascript'>parent.callback('上传成功')</script>");
    } catch (Exception e) {
        out.write("<script type='text/javascript'>parent.callback('上传失败')</script>");
        e.printStackTrace();
    }
}