java文件上传

表单必须加

`<form name="form1" action="" method="post" **enctype="multipart/form-data"**>

</form>`

//封装上传文件对象
private File headImg;
//封装上传文件类型的属性
private String headImgContentType;
//封装上传文件名的属性
private String headImgFileName;


//拿到保存文件的路径
            String path = "/upload";
            //根据相对路径获取绝对路径
            String realPath = ServletActionContext.getServletContext().getRealPath(path);
            System.out.println(realPath);
            //使用uuid文件名
            String uuid  = UUID.randomUUID().toString();
            uuid=uuid.replace("-", "");
            //拼接文件名
            String filename ="/user/"+ uuid + headImgFileName.substring(headImgFileName.lastIndexOf("."));
            //设置user头型的路径
            user.setHeadImg(filename);
            //上传文件
            FileInputStream fis = new FileInputStream(headImg);
            BufferedInputStream bis = new BufferedInputStream(fis);

            FileOutputStream fos = new FileOutputStream(realPath+filename);
            BufferedOutputStream bos = new BufferedOutputStream(fos);

            byte[] bs = new byte[1024];
            int len = 0;
            while((len = bis.read(bs)) != -1){
                bos.write(bs, 0, len);
            }
            bis.close();
            bos.close();