如何解决从 Java 中的 AWS S3 图像获取内容类型
URL url = new URL(urlString);
URI dataUri = null;
if (null != url) {
try (InputStream inStreamGuess = url.openStream();
InputStream inStreamConvert = url.openStream();
ByteArrayOutputStream os = new ByteArrayOutputStream()) {
String contentType = URLConnection.guessContentTypeFromStream(inStreamGuess);
if (null != contentType) {
...
}
但内容类型为空
解决方法
要使用 Java 获取 Amazon S3 存储桶中对象的内容类型,请使用适用于 Java V2 的 AWS 开发工具包。
使用返回 HeadObjectResponse 对象的 headObject 方法。然后调用: https://sdk.amazonaws.com/java/api/latest/software/amazon/awssdk/services/s3/model/HeadObjectResponse.html#contentType-- 方法。
有效的 Java V2 示例
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.s3.S3Client;
import software.amazon.awssdk.services.s3.model.*;
/**
* To run this AWS code example,ensure that you have setup your development environment,including your AWS credentials.
*
* For information,see this documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
*/
public class GetObjectContentType {
public static void main(String[] args) {
final String USAGE = "\n" +
"Usage:\n" +
" GetObjectContentType <bucketName> <keyName>>\n\n" +
"Where:\n" +
" bucketName - the Amazon S3 bucket name. \n\n"+
" keyName - the key name. \n\n";
if (args.length != 2) {
System.out.println(USAGE);
System.exit(1);
}
String bucketName = args[0];
String keyName = args[1];
Region region = Region.US_WEST_2;
S3Client s3 = S3Client.builder()
.region(region)
.build();
getContentType(s3,bucketName,keyName);
s3.close();
}
public static void getContentType (S3Client s3,String bucketName,String keyName) {
try {
HeadObjectRequest objectRequest = HeadObjectRequest.builder()
.key(keyName)
.bucket(bucketName)
.build();
HeadObjectResponse objectHead = s3.headObject(objectRequest);
String type = objectHead.contentType();
System.out.println("The object content type is "+type);
} catch (S3Exception e) {
System.err.println(e.awsErrorDetails().errorMessage());
System.exit(1);
}
}
}
版权声明:本文内容由互联网用户自发贡献,该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务,不拥有所有权,不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容, 请发送邮件至 dio@foxmail.com 举报,一经查实,本站将立刻删除。