[英]Read AWS s3 File to Java code
我试图从 AWS s3 读取文件到我的 java 代码:
File file = new File("s3n://mybucket/myfile.txt");
FileInputStream fileInput = new FileInputStream(file);
然后我得到一个错误:
java.io.FileNotFoundException: s3n:/mybucket/myfile.txt (No such file or directory) at java.io.FileInputStream.open(Native Method) at java.io.FileInputStream.(FileInputStream.java:146)
有没有办法从 AWS s3 打开/读取文件? 非常感谢!
Java 中的“文件”类不了解 S3 的存在。 以下是从 AWS 文档中读取文件的示例:
AmazonS3 s3Client = new AmazonS3Client(new ProfileCredentialsProvider());
S3Object object = s3Client.getObject(new GetObjectRequest(bucketName, key));
InputStream objectData = object.getObjectContent();
// Process the objectData stream.
objectData.close();
在 2019 年,有一种更好的方法可以从 S3 读取文件:
private final AmazonS3 amazonS3Client = AmazonS3ClientBuilder.standard().build();
private Collection<String> loadFileFromS3() {
try (final S3Object s3Object = amazonS3Client.getObject(BUCKET_NAME,
FILE_NAME);
final InputStreamReader streamReader = new InputStreamReader(s3Object.getObjectContent(), StandardCharsets.UTF_8);
final BufferedReader reader = new BufferedReader(streamReader)) {
return reader.lines().collect(Collectors.toSet());
} catch (final IOException e) {
log.error(e.getMessage(), e)
return Collections.emptySet();
}
}
在java中读取S3文件的步骤可以是:
1 >>>
BasicAWSCredentials awsCreds = new BasicAWSCredentials("accessKey", "secretKey");
AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
.withCredentials(new AWSStaticCredentialsProvider(awsCreds))
.withRegion("region_name_here").build();
2 >>>
S3Object object = s3Client.getObject(new GetObjectRequest("bucketName", "key"));
3 >>>
BufferedReader reader = new BufferedReader(new InputStreamReader(object.getObjectContent()));
String s = null;
while ((s = reader.readLine()) != null)
{
System.out.println(s);
//your business logic here
}
谢谢。
如果文件的内容是字符串,则可以使用getObjectAsString 。 否则,您可以在getObjectContent()
上使用IOUtils.toByteArray将文件内容读入字节数组。
显然,这些最适合用于易于放入内存的小型 S3 对象。
private final AmazonS3 amazonS3Client = AmazonS3ClientBuilder.standard().build();
private String loadStringFromS3() {
try {
return amazonS3Client.getObjectAsString(BUCKET_NAME, FILE_NAME);
} catch (final IOException e) {
log.error(e.getMessage(), e)
return null;
}
}
private byte[] loadDataFromS3() {
try (final S3Object s3Object = amazonS3Client.getObject(BUCKET_NAME, FILE_NAME)) {
return IOUtils.toByteArray(s3Object.getObjectContent());
} catch (final IOException e) {
log.error(e.getMessage(), e)
return null;
} finally {
IOUtils.closeQuietly(object, log);
}
}
我们也可以使用software.amazon.awssdk:s3
//Assuming the credentials are read from Environment Variables, so no hardcoding here
S3Client client = S3Client.builder()
.region(regionSelected)
.build();
GetObjectRequest getObjectRequest = GetObjectRequest.builder()
.bucket(bucketName)
.key(fileName)
.build();
ResponseInputStream<GetObjectResponse> responseInputStream = client.getObject(getObjectRequest);
InputStream stream = new ByteArrayInputStream(responseInputStream.readAllBytes());
System.out.println("Content :"+ new String(responseInputStream.readAllBytes(), StandardCharsets.UTF_8));
这是我的解决方案。 我正在使用弹簧靴 2.4.3
创建亚马逊 s3 客户端
AmazonS3 amazonS3Client = AmazonS3ClientBuilder
.standard()
.withRegion("your-region")
.withCredentials(
new AWSStaticCredentialsProvider(
new BasicAWSCredentials("your-access-key", "your-secret-access-key")))
.build();
创建一个亚马逊转账客户端。
TransferManager transferManagerClient = TransferManagerBuilder.standard()
.withS3Client(amazonS3Client)
.build();
在/tmp/{your-s3-key} 中创建一个临时文件,以便我们可以将我们下载的文件放在这个文件中。
File file = new File(System.getProperty("java.io.tmpdir"), "your-s3-key");
try {
file.createNewFile(); // Create temporary file
} catch (IOException e) {
e.printStackTrace();
}
file.mkdirs(); // Create the directory of the temporary file
然后,我们使用传输管理器客户端从 s3 下载文件
// Note that in this line the s3 file downloaded has been transferred in to the temporary file that we created
Download download = transferManagerClient.download(
new GetObjectRequest("your-s3-bucket-name", "your-s3-key"), file);
// This line blocks the thread until the download is finished
download.waitForCompletion();
现在 s3 文件已成功传输到我们创建的临时文件中。 我们可以得到临时文件的InputStream。
InputStream input = new DataInputStream(new FileInputStream(file));
因为不再需要临时文件,我们就删除它。
file.delete();
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