AWS S3 学习小结

大家好，又见面了，我是你们的朋友全栈君。如果您正在找激活码,请点击查看最新教程,关注关注公众号 “全栈程序员社区” 获取激活教程,可能之前旧版本教程已经失效.最新Idea2022.1教程亲测有效,一键激活。

Jetbrains全系列IDE稳定放心使用

1.首先，这个是AWS的开发资源使用文档：AWS开发文档，AWS官网 – S3教程

2.我们可以通过AWS Cli和Java Api来操作AWS 的 S3，AWS Cli安装教程：AWS Cli安装

3.Linux下连接S3前，需要先获取到AWS的IAM的accessKey 和secretKey，那么获取方式是：

服务->安全、身份与合规 分组下的 IAM->用户->安全证书->创建访问密钥

AWS S3 学习小结

然后，

4.获取到了key之后，以下通过AmazonS3来操作S3：

1) 上传文件到S3

public static String uploadToS3(AmazonS3 s3, File tempFile, String remoteFileName, String bucketName) throws IOException {
        try {
            //上传文件
            s3.putObject(new PutObjectRequest(bucketName, remoteFileName, tempFile).withCannedAcl(CannedAccessControlList.PublicRead));
            //获取一个request
            GeneratePresignedUrlRequest urlRequest = new GeneratePresignedUrlRequest(
                    bucketName, remoteFileName);
            //生成公用的url
            URL url = s3.generatePresignedUrl(urlRequest);
            System.out.println("=========URL=================\n" + url + "\n============URL=============");
            return url.toString();
        } catch (AmazonServiceException ase) {
            ase.printStackTrace();
        } catch (AmazonClientException ace) {
            ace.printStackTrace();
        }
        return null;
    }

2)下载文件到本地(两种方法自己权衡吧)


import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.GetObjectRequest;
import com.amazonaws.services.s3.model.S3Object;
import com.amazonaws.services.s3.model.S3ObjectInputStream;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import com.amazonaws.ClientConfiguration;

/**
 * @description:
 * @create: 2019/4/26 16:24
 **/
public class DownloadFile {

    /**
     * @Title: downFromS3
     * @Description: 将文件下载到本地路径
     * @param @param remoteFileName 文件名
     * @param @param path 下载的路径
     * @param @throws IOException    设定文件
     * @return void    返回类型
     * @throws
     */
    public static void downFromS3(AmazonS3 s3, String remoteFileName, String path, String bucketName) throws IOException {
        try {
            GetObjectRequest request  = new GetObjectRequest(bucketName,remoteFileName);
            s3.getObject(request,new File(path));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public static String millToDate(long mills) {
        SimpleDateFormat sdf =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        return sdf.format(new Date(Long.valueOf(mills+"")));
    }

    public static void main(String[] args)
    {
        ClientConfiguration clientConfig = new ClientConfiguration();
        clientConfig.setConnectionTimeout(60*60*1000);
        clientConfig.setSocketTimeout(60*60*1000);

        // (AWS_ACCESS_KEY_ID (or AWS_ACCESS_KEY) and AWS_SECRET_KEY (or AWS_SECRET_ACCESS_KEY)
        System.setProperty("aws.accessKeyId","asd");
        System.setProperty("aws.secretKey","tTc");

        String bucket_name = "buk";
        String key_name = "testDir/files.zip";

        System.out.format("Downloading %s from S3 bucket %s... on %s\n", key_name, bucket_name, millToDate(System.currentTimeMillis()));
        final AmazonS3 s3 = AmazonS3ClientBuilder.standard().withCredentials(DefaultAWSCredentialsProviderChain.getInstance())
//.withClientConfiguration(clientConfig).withPathStyleAccessEnabled(true)
.withRegion(Regions.US_EAST_2).build();
        try {
            S3Object o = s3.getObject(bucket_name, key_name);
            S3ObjectInputStream s3is = o.getObjectContent();
            FileOutputStream fos = new FileOutputStream(new File("C:\\Users\\Desktop\\rawfiles.Zip"));
            byte[] read_buf = new byte[1024];
            int read_len = 0;
            while ((read_len = s3is.read(read_buf)) > 0) {
                fos.write(read_buf, 0, read_len);
            }
            s3is.close();
            fos.close();
        } catch (AmazonServiceException e) {
            System.err.println(e.getErrorMessage());
            System.exit(1);
        } catch (FileNotFoundException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        } catch (IOException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }
        System.out.println("Done!"+ millToDate(System.currentTimeMillis()));
    }
}

3) 测试

import com.amazonaws.AmazonServiceException;
import com.amazonaws.auth.DefaultAWSCredentialsProviderChain;
import com.amazonaws.regions.Regions;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.S3Object;
import com.amazonaws.services.s3.model.S3ObjectInputStream;
import com.amazonaws.auth.BasicAWSCredentials;
import com.amazonaws.regions.Region;
import com.amazonaws.services.s3.model.Bucket;
import com.amazonaws.services.s3.transfer.TransferManager;
import utils.DownloadFile;
import utils.UploadFile;

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


public class testConnection {

    static AmazonS3         s3;
    static TransferManager tx;
    private static String AWS_ACCESS_KEY = "abc";
    private static String AWS_SECRET_KEY = "efg";
    static final String bucketName = "hij";

    static {
        ClientConfiguration config = new ClientConfiguration();
        config.setConnectionTimeout(10000);
        config.setSocketTimeout(300000);
        s3 = new AmazonS3Client(new BasicAWSCredentials(AWS_ACCESS_KEY, AWS_SECRET_KEY), config);
        Region usWest2 = Region.getRegion(Regions.US_EAST_1);
        s3.setRegion(usWest2);
    }

    public static void main(String[] args) {
        
        //枚举bucket
        List<Bucket> buckets = s3.listBuckets();
        for (Bucket bucket : buckets) {
            System.out.println("Bucket: " + bucket.getName() + bucket.getOwner());
        }

        // 上传
        try {
            UploadFile.uploadToS3(s3, new File("D:\\workplace\\xml_\\i2.xml"), "testFile", bucketName);
        } catch (IOException e) {
            e.printStackTrace();
        }

        // 下载
        try {
            DownloadFile.downFromS3(s3, "test", "C:\\Users\\Desktop\\in.xml", bucketName);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    // 按行读取S3的GZip
    public void test13() {
        System.setProperty("aws.accessKeyId", "abc");
        System.setProperty("aws.secretKey", "asd");
        String bucket_name = "test";
        String key_name = "data_date=20190814/inst.txt.gz";

        System.out.format("Downloading %s from S3 bucket %s...\n", key_name, bucket_name);
        final AmazonS3 s3 = AmazonS3ClientBuilder.standard().withCredentials(DefaultAWSCredentialsProviderChain.getInstance()).withRegion(Regions.US_EAST_2).build();
        try {
            S3Object o = s3.getObject(bucket_name, key_name);
            S3ObjectInputStream s3is = o.getObjectContent();
            InputStream in = new GZIPInputStream(s3is);
            BufferedReader in2=new BufferedReader(new InputStreamReader(in));
            String y="";
            while((y=in2.readLine())!=null){//一行一行读

                System.out.println(y);

            }
            s3is.close();
        } catch (AmazonServiceException e) {
            System.err.println(e.getErrorMessage());
            System.exit(1);
        } catch (FileNotFoundException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        } catch (IOException e) {
            System.err.println(e.getMessage());
            System.exit(1);
        }

    }
}

5. 以下通过S3Client来操作S3：

1) 小文件流上传到S3

    public void putObject(String bucket, String key, String filePath) throws IOException {
        s3.putObject(PutObjectRequest.builder().bucket(bucket).key(key).build(),
                RequestBody.fromByteBuffer(ByteBuffer.wrap(inputStream2ByteArray(filePath))));
    }

    public void putObject(String bucket, String key, byte[] bytes) {
        s3.putObject(PutObjectRequest.builder().bucket(bucket).key(key).build(),
                RequestBody.fromByteBuffer(ByteBuffer.wrap(bytes)));
    }

    public static byte[] inputStream2ByteArray(String filePath) throws IOException {
        try (InputStream in = new FileInputStream(filePath)) {
            byte[] data = toByteArray(in);
            return data;
        }
    }

2) 分部上传文件流到S3

    /**
     * Get upload id from s3
     */
    public static String getUploadId(String bucketName, String key, Region region){
        s3 = S3Client.builder().region(region).build();
        // First create a multipart upload and get upload id
        CreateMultipartUploadRequest createMultipartUploadRequest = CreateMultipartUploadRequest.builder()
                .bucket(bucketName).key(key)
                .build();
        CreateMultipartUploadResponse response = s3.createMultipartUpload(createMultipartUploadRequest);
        String uploadId = response.uploadId();
        return uploadId;
    }
    /**
     * Multipart upload
     */
    public static void multipartUpload(String bucketName, String key,
                                       List<String> etags, List<CompletedPart> completedParts,
                                       String uploadId, byte[] cbuf, int off) {
        Region region = Region.US_EAST_2;
        s3 = S3Client.builder().region(region).build();
        //record upload end tag
        ByteBuffer bf = ByteBuffer.wrap(cbuf);
        UploadPartRequest uploadPartRequest = UploadPartRequest.builder().bucket(bucketName).key(key)
                .uploadId(uploadId)
                .partNumber(off).build();
        String etag = s3.uploadPart(uploadPartRequest, RequestBody.fromByteBuffer(bf)).eTag();
        CompletedPart part = CompletedPart.builder().partNumber(off).eTag(etag).build();
        etags.add(etag);
        completedParts.add(part);
    }

    /**
     * Complete multipart upload
     */
    public static void completeMultipartUpload(String bucketName, String key, List<CompletedPart> completedParts, String uploadId) {
        // Finally call completeMultipartUpload operation to tell S3 to merge all uploaded
        // parts and finish the multipart operation.
        CompletedMultipartUpload completedMultipartUpload = CompletedMultipartUpload.builder().parts(completedParts).build();
        CompleteMultipartUploadRequest completeMultipartUploadRequest =
                CompleteMultipartUploadRequest.builder().bucket(bucketName).key(key).uploadId(uploadId)
                        .multipartUpload(completedMultipartUpload).build();
        s3.completeMultipartUpload(completeMultipartUploadRequest);
    }

其中的先后顺序是：getUploadId -> multipartUpload … -> completeMultipartUpload

注：

1. 遇到：AWS error downloading object from S3, “profile file cannot be null”，参考：https://stackoverflow.com/questions/41796355/aws-error-downloading-object-from-s3-profile-file-cannot-be-null

2. 遇到：SocketTimeoutException: Read timed out，参考：http://www.unixresources.net/faq/28195217.shtml

3. 遇到：S3的Status Code: 404 指的是 bucket 名字写错了

4. 遇到：S3的Status Code: 301，那么检查一下Region对不对。

5. 遇到：Unable to unmarshall response (null). Response Code: 200, Response Text: OK… ，问题在于调用s3.getObject()的时候，本地已存在相同名字的文件了。

6. 遇到：Your socket connection to the server was not read from or written to within the timeout period… ，解决这个问题可能需要设置S3 configuration的retry policy，参考：Recurrent “Idle connection..” exception in S3Client.putObject