java后台简单从腾讯云下载文件通知前端以附件的形式保存

桃扇骨 2022-10-03 00:40 46阅读 0赞

腾讯云对象存储和阿里云差不多

这是我的配置

/**
         *  腾讯云client
         * @return COSClient
         */
        public static COSClient getCOSClient() {
     long appId = 00000;
            String secretId = "";
            String secretKey = "";
            // 1 初始化身份信息
            COSCredentials cred = new BasicCOSCredentials(appId , secretId, secretKey);
            // 2 设置 Bucket 的区域, XML的区域详细信息请参见 可用地域(https://www.qcloud.com/document/product/436/6224) 文档
            ClientConfig clientConfig = new ClientConfig(new Region("cos.na-toronto"));
            // 3 生成 cos 客户端
            return new COSClient(cred, clientConfig);
        }

下载代码

@Autowired
        private COSClient cosClient;
    
        @Override
        public MessageVo getDownLoadFile(String fileName, String cosKey, HttpServletResponse response, HttpServletRequest request) {
            MessageVo messageVo = MessageVoUtil.getMessageVo();
            try {
    
                // 从腾讯云下载文件
                GetObjectRequest getObjectRequest = new GetObjectRequest(ManageStaticParam.COSCLIENT_BUCKET_TEST, "/yu/"+cosKey);//bucketName需要自己设置
                COSObject cosObject = cosClient.getObject(getObjectRequest);
                // 已缓冲的方式从字符输入流中读取文本，缓冲各个字符，从而提供字符、数组和行的高效读取
                BufferedReader reader = new BufferedReader(new InputStreamReader(cosObject .getObjectContent()));
                COSObjectInputStream cosObjectInput = cosObject.getObjectContent();
                // 缓冲文件输出流
                BufferedOutputStream outputStream = new BufferedOutputStream(response.getOutputStream());
                // 通知浏览器以附件形式下载
    //            response.setHeader("Content-Disposition","attachment;filename="+ URLEncoder.encode(fileName,"UTF-8"));
    
                response.setContentType("application/doc");
                final String userAgent = request.getHeader("USER-AGENT");
                if(StringUtils.contains(userAgent, "MSIE")){
        //IE浏览器
                    fileName = URLEncoder.encode(fileName,"UTF-8");
                }else if(StringUtils.contains(userAgent, "Mozilla")){
        //google,火狐浏览器
                    fileName = new String(fileName.getBytes(), "ISO8859-1");
                }else{
                    fileName = URLEncoder.encode(fileName,"UTF-8");//其他浏览器
                }
                response.addHeader("Content-Disposition", "attachment;filename=" +fileName);//这里设置一下让浏览器弹出下载提示框，而不是直接在浏览器中打开
    
                // 进行解码
                BASE64Decoder base64Decoder = new BASE64Decoder();
                byte[] car= new byte[1024];
                while (true) {
                    String line = reader.readLine();
                    if (line == null) break;
                    car =  base64Decoder.decodeBuffer(line);
                    outputStream.write(car);
                   }
                    reader.close();
    
    //                byte[] car = new byte[1024];
    //                int L;
    //
    //                while((L = cosObjectInput.read(car)) != -1){
    //                    System.out.println(car+"=========="+car.length);
    //                    if (car.length!=0){
    //                        outputStream.write(car, 0,L);
    //                    }
    //                }
                    outputStream.flush();
                    outputStream.close();
                    messageVo.setCode(ReturnCodeEnum.处理成功.getStatenum());
                return  messageVo;
            } catch (IOException e) {
                e.printStackTrace();
                messageVo.setCode(ReturnCodeEnum.请求实体不存在.getStatenum());
                messageVo.setData(" Backend file write error ！！！");
                return messageVo;
            } catch (CosServiceException e){
                messageVo.setCode(ReturnCodeEnum.请求实体不存在.getStatenum());
                messageVo.setData(" The request entity does not exist  ！！！");
                return messageVo;
            }
        }

注意：在实际使用该方法下载的过程中，可能遇到服务器不报错，但就是下载不下来文件的问题，这样有可能是前端页面发出下载请求的方式有误，不能使用AJAX的get方式访问该方法，因为Ajax能够返回的数据格式只能为html,script,json,xml，不接受流的形式。笔者使用的方式是用window.location.href访问，或者使用from表单提交方式（GET/POST）。

腾讯开放平台文档

https://cloud.tencent.com/document/product/436/10199\#.E7.AE.80.E5.8D.95.E6.96.87.E4.BB.B6.E4.B8.8A.E4.BC.A0

阿里云下载链接

http://blog.csdn.net/qq\_35498405/article/details/77942817

转载于:https://www.cnblogs.com/memoryXudy/p/7805253.html