Amazon SDK for Java

[rainit2006]

---

[rainit2006]

AmazonS3Client

■引用库

import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.AccessControlList;
import com.amazonaws.services.s3.model.GroupGrantee;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.ObjectMetadata;
import com.amazonaws.services.s3.model.Permission;
import com.amazonaws.services.s3.model.PutObjectRequest;
import com.amazonaws.services.s3.model.S3Object;
import com.amazonaws.services.s3.model.S3ObjectSummary;

■AmazonS3Clientを利用するコード例

import com.amazonaws.AmazonClientException;
import com.amazonaws.regions.Region;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3Client;
import com.amazonaws.services.s3.model.ListObjectsRequest;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.s3.model.S3Object;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;

import javax.annotation.PreDestroy;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

@Component
public class SchemaEnumerator {
    private static final Logger LOG = LoggerFactory.getLogger(SchemaEnumerator.class);

    private final AmazonS3Client s3 = new AmazonS3Client();

    @Value("${hive.schema.bucket}")
    private String schemaDirectory;

    @Value("${aws.active.schema.bucket}")
    protected String activeSchemaBucket;

    @Value("${aws.active.schema.key}")
    protected String activeSchemaKey;

    public SchemaEnumerator() {
        s3.setRegion(Region.getRegion(Regions.EU_WEST_1));
    }

    @PreDestroy
    private void shutdown() {
        s3.shutdown();
    }

    /**
     * Returns the schema that is considered as the preferred schema to run queries on, usually this is the latest one.
     * It is configured externally so it can be easily changed by portal administrators.
     *
     * @return preferred schema
     */
    public String getPreferredQueryBuilderSchema() {
        String queryBuilderSchema;
        try {
            AmazonS3Client s3 = new AmazonS3Client();
            S3Object activeSchema = s3.getObject(activeSchemaBucket, activeSchemaKey);
            try (final InputStream is = activeSchema.getObjectContent();
                 final InputStreamReader reader = new InputStreamReader(is, "utf-8");
                 final BufferedReader br = new BufferedReader(reader)) {
                queryBuilderSchema = br.readLine();
            } catch (IOException e) {
                LOG.error("Could not read from S3", e);
                queryBuilderSchema = "";
            }

        } catch (AmazonClientException e) {
            LOG.error("AmazonClientException when reading active-schema.txt", e);
            queryBuilderSchema = "";
        }
        LOG.info("preferredQueryBuilderSchema='" + queryBuilderSchema + "'");
        return queryBuilderSchema;
    }

    public List<String> getSchemas() {
        boolean more;

        List<String> schemas = new ArrayList<>();

        ObjectListing listing = s3.listObjects(new ListObjectsRequest().withBucketName(schemaDirectory).withPrefix("schema-").withDelimiter("/"));
        do {
            for (String prefix : listing.getCommonPrefixes()) {
                String schemaName = prefix.substring(0, prefix.length() - 1); // remove trailing /
                schemas.add(schemaName);
            }

            more = listing.isTruncated();
            if (more) {
                listing = s3.listNextBatchOfObjects(listing);
            }
        } while (more);

        return schemas;
    }

}