java 网络资源下载

柔光的暖阳◎ 2022-02-15 17:23 242阅读 0赞

比如文件上传在OSS系统上面，那么我怎么让客户端下载到本地？  
Services实现层：

attachment绝对路径，比如：[https://imgsrc.baidu.com/baike/pic/item/dcc451da81cb39db5aacb0c8dc160924aa1830c4.jpg][https_imgsrc.baidu.com_baike_pic_item_dcc451da81cb39db5aacb0c8dc160924aa1830c4.jpg]  
public void fileDownload(HttpServletRequest request, HttpServletResponse response, String attachment) \{  
        // 获取上下文对象  
        ServletContext servletContext = request.getSession().getServletContext();  
        // 获取文件资源的路径  
        String path = attachment;//servletContext.getRealPath(Constants.REPORT\_REPORTFILEPATH);  
        log.debug(path);

URL url = null;  
        InputStream openStream = null;  
        try (OutputStream fos = response.getOutputStream();) \{  
            url = new URL(attachment);  
            openStream = url.openStream();  
            String mimeType = servletContext.getMimeType(attachment);  
            if (mimeType == null) \{  
                mimeType = "application/octet-stream";  
            \}  
            response.setContentType(mimeType);  
            String headerkey = "Content-Disposition";  
            String fileName = attachment.substring(attachment.lastIndexOf("/") + 1);  
            String headerValue = String.format("attachment;filename=\\"%s\\"", fileName);  
            response.setHeader(headerkey, headerValue);

byte buff\[\] = new byte\[BUFF\_SIZE\];  
            int flag = -1;  
            while ((flag = openStream.read(buff)) != -1) \{  
                fos.write(buff, 0, flag);  
            \}  
        \} catch (Exception e) \{  
            e.printStackTrace();  
            log.error("ProjectDetailServiceImpl fileDownload() have an exception \{\} = ", e);  
        \} finally \{  
            try \{  
                if (openStream != null) \{  
                    openStream.close();  
                \}  
            \} catch (IOException e) \{  
                e.printStackTrace();  
            \}

\}  
    \}

[https_imgsrc.baidu.com_baike_pic_item_dcc451da81cb39db5aacb0c8dc160924aa1830c4.jpg]: https://imgsrc.baidu.com/baike/pic/item/dcc451da81cb39db5aacb0c8dc160924aa1830c4.jpg