1      背景介绍 & 效果展示

通过JAVA SDK可判断文件是否存在，并不需要下载对象操作，如果对象存在会返回对象的类型和对象大小，若对象不存在则返回相应的错误码，效果如下。

图1 对象存在会返回对象的类型和对象大小

图2 对象不存在则返回相应的错误码

2      java代码参考

前提：

需要先下载OBS最新的JAVA SDK，参考官网链接：https://developer.huaweicloud.com/sdk?OBS，并在自己的项目中导入SDK中的JAR包。

       public static void main(String[] args) throws IOException {

                   // 需要将endPoint/ak/sk更新为实际信息

                   String endPoint = "https://your-endpoint";

                   String ak = "*** Provide your Access Key ***";

                   String sk = "*** Provide your Secret Key ***";

                   // 创建ObsClient实例

                   ObsClient obsClient = new ObsClient(ak, sk, endPoint);

                   try

                  {

                                        String bucketName = "bucketXXX";                // 需要将bucketName更新为实际信息

                                       String objectName = "objectXXX";                // 需要将objectName更新为实际信息

                                      ObjectMetadata metadata = obsClient.getObjectMetadata(bucketName, objectName);     

                                      System.out.println("---------------\nobject exist!");

                                      System.out.println("\tcontentType: " + metadata.getContentType());

                                      System.out.println("\tcontentLength: " + metadata.getContentLength());

                  }

                  catch (ObsException e)

                  {

                      System.out.println("Response Code: " + e.getResponseCode());

                      System.out.println("Error Message: " + e.getErrorMessage());

                      System.out.println("Error Code:       " + e.getErrorCode());

                      System.out.println("Request ID:      " + e.getErrorRequestId());

                      System.out.println("Host ID:           " + e.getErrorHostId());

                      if(e.getResponseCode() == 404) {

                             System.out.println("---------------\nobject doesn't exist!");

                      }

                  }

}

3      附录链接

OBS JAVA SDK使用方法，官网参考链接：https://support.huaweicloud.com/sdk-java-devg-obs/zh-cn_topic_0142815558.html