阿里云oss service代码

以下是使用Java SDK操作阿里云OSS的示例代码：

import com.aliyun.oss.OSS;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.model.Bucket;
import com.aliyun.oss.model.ObjectListing;
import com.aliyun.oss.model.OSSObject;
import com.aliyun.oss.model.PutObjectResult;

import java.io.File;
import java.io.InputStream;
import java.util.List;

public class AliyunOSSExample {

    private static final String accessKeyId = "your_access_key_id";
    private static final String accessKeySecret = "your_access_key_secret";
    private static final String endpoint = "http://oss-cn-hangzhou.aliyuncs.com";
    private static final String bucketName = "your_bucket_name";

    public static void main(String[] args) {

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

        // 列举所有的Bucket
        List<Bucket> bucketList = ossClient.listBuckets();
        for (Bucket bucket : bucketList) {
            System.out.println(bucket.getName());
        }

        // 上传文件
        String objectName = "example.txt";
        InputStream inputStream = AliyunOSSExample.class.getResourceAsStream("/example.txt");
        PutObjectResult result = ossClient.putObject(bucketName, objectName, inputStream);
        System.out.println(result.getETag());

        // 下载文件
        OSSObject ossObject = ossClient.getObject(bucketName, objectName);
        InputStream content = ossObject.getObjectContent();
        // do something with content

        // 列举指定Bucket下的所有文件
        ObjectListing objectListing = ossClient.listObjects(bucketName);
        List<OSSObjectSummary> objectSummaries = objectListing.getObjectSummaries();
        for (OSSObjectSummary objectSummary : objectSummaries) {
            System.out.println(objectSummary.getKey());
        }

        // 删除文件
        ossClient.deleteObject(bucketName, objectName);

        // 关闭OSSClient实例
        ossClient.shutdown();
    }
}

在上述代码中，我们通过accessKeyId和accessKeySecret来进行身份验证，然后通过endpoint指定OSS的访问地址，bucketName指定Bucket的名称。接着，我们通过OSSClient实例可以进行Bucket的列举、文件上传、下载、文件列表查询、文件删除等操作。最后需要调用shutdown()方法来关闭OSSClient实例。