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How FormData implements Ajax request to upload files (code attached)

不言Original: 2018-08-15 10:55:171774browse

The content of this article is about how FormData implements Ajax request to upload files (with code). It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.

Servlet3.0 began to provide a series of annotations to configure Servlet, Filter, Listener, etc. This method can greatly simplify the configuration of a large amount of xml during development. Starting from this version, web.xml is no longer needed, and the corresponding configuration can also be completed using relevant annotations.

a. Select upload

b: Display in the background

c: Uploaded folder

html code:

<!DOCTYPE html><html lang="en"><head>
    <meta charset="UTF-8">
    <title>Ajax上传</title>
    <script src="js/jquery-1.12.4.js"></script></head><body>
    <h1>文件上传</h1>
    <form id="f" enctype="multipart/form-data">
        UserName:<input type="text" name="userName"><br/>
        File1:<input type="file" name="file"><br/>
        File2:<input type="file" name="file"><br/>
        <input type="button" id="btn" value="提交">
    </form></body><script>
    $(function () {
        $("#btn").on("click",function () {            
        //使用FormData对象来提交整个表单，它支持文件的上传
            var formData=new FormData(document.getElementById("f"));            
            //额外带来一些数据            
            formData.append("age",14);            
            //使用ajax提交            
            $.ajax("ajaxUpload",{
                type:"post",
                data:formData,
                processData:false,//告诉jquery不要去处理请求的数据格式                
                contentType:false,//告诉jquery不要设置请求头的类型                
                success:function (data) {
                    alert(data);
                }
            });
        })
    })
    </script>
    </html>

java background code:

@WebServlet("/ajaxUpload")
@MultipartConfig //开启上传功能/**
 * @author hh */
 public class FileUploadServlet extends HttpServlet {
    @Override    
    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf-8");        
        //获取用户名
        String userName=req.getParameter("userName");        
        //获取年龄
        String age=req.getParameter("age");
        System.out.println(userName);
        System.out.println(age);        
        //获取项目部署的绝对路径
        String uploadPath=req.getServletContext().getRealPath("/photos");        
        //构建上传的文件夹
        File dir=new File(uploadPath);        
        if(!dir.exists()){
            dir.mkdir();
        }        
        //获取所有上传的Part
       Collection<Part> parts= req.getParts();        
       for (Part part:parts) {            
       //判断上传的类型是否为空，如果为空则不执行上传
            if(part.getContentType()!=null){                
            //获取文件名
                String fileName=part.getSubmittedFileName();                
                //执行上传
                part.write(uploadPath+File.separator+fileName);
            }
        }        
        //响应上传成功
        resp.getWriter().println("uplaod success");
    }
}

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