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

/**
* 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);
}

@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[];
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;
}
}