Java Web 文件上传

工具

smartupload.jar

使用

页面部分

• 必须使用POST提价
• 表单属性必须有enctype="multipart/form-data"

<form action="toUpload" method="post" enctype="multipart/form-data" >
    书名:<input type="text" name="bookName"/><br>
    图片:<input type="file" name="自定义名称"/><br>
    <input type="submit" value="提交"/>
</form>

文件上传

public void upload(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    try {
        //上传文件
        SmartUpload su=new SmartUpload();
        //获得pageContext对象
        JspFactory factory=JspFactory.getDefaultFactory();
        PageContext pagecontext=factory.getPageContext(this, request,response, null,false,1024,true);
        su.initialize(pagecontext);
        su.setCharset("utf-8");
        //实现文件数据的上传
        su.upload();
        File file = su.getFiles().getFile(0);
        //得到文件的基本信息
        String filename=file.getFileName();
        String type=file.getContentType();
        String url="uploadfile/"+filename;
        //将上传文件保存到指定目录
        file.saveAs(url, SmartUpload.SAVE_VIRTUAL);
    } catch (SmartUploadException e) {
        e.printStackTrace();
    }
}

文件下载

String name=request.getParameter("filename");
String url="uploadfile/"+name;
//将响应的内容设置为通用的二进制流
response.setContentType("application/octet-stream");
//attachment 告诉浏览器以附件的方式下载文件(弹出下载框)
name=URLEncoder.encode(name,"utf-8");
response.addHeader("Content-Disposition","attachment;filename="+name); request.getRequestDispatcher(url).forward(request, response);
//清空缓冲区:将服务端缓冲区的文件内容,立即权并不传送给客户端
response.flushBuffer();