本文介绍如何判断指定文件(Object)是否存在。

示例代码

以下代码用于判断examplebucket中的exampleobject.txt文件是否存在。

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;

public class Demo {
    public static void main(String[] args) throws Exception {
        // Endpoint以华东1(杭州)为例,其它Region请按实际情况填写。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // 阿里云账号AccessKey拥有所有API的访问权限,风险很高。强烈建议您创建并使用RAM用户进行API访问或日常运维,请登录RAM控制台创建RAM用户。
        String accessKeyId = "yourAccessKeyId";
        String accessKeySecret = "yourAccessKeySecret";
        // 填写Bucket名称,例如examplebucket。
        String bucketName = "examplebucket";
        // 填写不包含Bucket名称在内的Object完整路径,例如exampleobject.txt。
        String objectName = "exampleobject.txt";

        // 创建OSSClient实例。
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);

        try {
            // 判断文件是否存在。如果返回值为true,则文件存在,否则存储空间或者文件不存在。
            // 设置是否进行重定向或者镜像回源。默认值为true,表示忽略302重定向和镜像回源;如果设置isINoss为false,则进行302重定向或者镜像回源。
            //boolean isINoss = true;
            boolean found = ossClient.doesObjectExist(bucketName, objectName);
            //boolean found = ossClient.doesObjectExist(bucketName, objectName, isINoss);
            System.out.println(found);
        } catch (OSSException oe) {
            System.out.println("Caught an OSSException, which means your request made it to OSS, "
                    + "but was rejected with an error response for some reason.");
            System.out.println("Error Message:" + oe.getErrorMessage());
            System.out.println("Error Code:" + oe.getErrorCode());
            System.out.println("Request ID:" + oe.getRequestId());
            System.out.println("Host ID:" + oe.getHostId());
        } catch (ClientException ce) {
            System.out.println("Caught an ClientException, which means the client encountered "
                    + "a serious internal problem while trying to communicate with OSS, "
                    + "such as not being able to access the network.");
            System.out.println("Error Message:" + ce.getMessage());
        } finally {
            if (ossClient != null) {
                ossClient.shutdown();
            }
        }
    }
}      

相关文档

关于判断文件是否存在的完整示例代码,请参见GitHub示例