Tag Archives: aws

spring

How to get rid of AmazonClientException when using Spring Cloud AWS with spring-boot

I was recently trying to list number of files from S3, and read those files one by one in a service. For doing this I was using spring-boot 2.0.0.RELEASE, spring-cloud-starter-aws (Edgware.SR2) library for auto-configuring my credentials.

I configured my credentials by following the official documentation. You can give that a read in your free time. TLDR; all we have to do if we are using spring-boot to auto-configure your Amazon S3 client is to populate the following properties in your applications.properties or application.yaml file.

cloud.aws.region.static
cloud.aws.credentials.secretKey
cloud.aws.credentials.accessKey

Once you configure these properties, spring-boot should auto-configure aws client for you. But this did not happen for me. When I have these properties filled out, and run the project, I got the following exception.

Caused by: java.lang.NoClassDefFoundError: com/amazonaws/AmazonClientException
	at org.springframework.cloud.aws.context.annotation.OnAwsCloudEnvironmentCondition.matches(OnAwsCloudEnvironmentCondition.java:37) ~[spring-cloud-aws-context-1.2.2.RELEASE.jar:1.2.2.RELEASE]
	at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:109) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	at org.springframework.context.annotation.ConfigurationClassParser.processConfigurationClass(ConfigurationClassParser.java:217) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	at org.springframework.context.annotation.ConfigurationClassParser.processImports(ConfigurationClassParser.java:606) ~[spring-context-5.0.4.RELEASE.jar:5.0.4.RELEASE]
	... 14 common frames omitted
Caused by: java.lang.ClassNotFoundException: com.amazonaws.AmazonClientException
	at java.net.URLClassLoader.findClass(URLClassLoader.java:381) ~[na:1.8.0_152]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_152]
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:338) ~[na:1.8.0_152]
	at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_152]
	... 18 common frames omitted

For some reason, spring-boot latest version does not go hand in hand with spring-cloud-dependencies. I tried downgrading spring-boot version and use 1.5.9.RELEASE but then didn’t end up solving the problem. I found out that the problem was that the amazon-java-aws-core library had an upgrade and spring does not handle that well enough, which causes the application to fail miserably at runtime. All I had to do was to downgrade the amazon-java-aws-core library.

spring-cloud-starter-aws (Edgware.SR2) uses amazon-java-aws-core version 1.11.125 which was causing the AmazonClientException. I had to change the following to my pom file.

<!-- Exclude aws-java-sdk-core -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-aws</artifactId>
<exclusions>
<exclusion>
<groupId>com.amazonaws</groupId>
<artifactId>aws-java-sdk-core</artifactId>
</exclusion>
</exclusions>
</dependency>
<!-- Include the right version of the dependency -->
<dependency>
<groupId>com.amazonaws</groupId>
<artifactId>aws-java-sdk-core</artifactId>
<version>1.11.106</version>
</dependency>
view raw pom.xml hosted with ❤ by GitHub
This will fix the AmazonClientException and enables spring-cloud-starter-aws to auto-configure the AmazonS3 client.

It is as simple as autowiring your ResourcePatternResolver bean and using it to list all the objects inside the bucket.

 

@Autowired
private ResourcePatternResolver resourcePatternResolver;

public List listS3Files(String bucketName) throws IOException {
  final Resource[] resources = resourcePatternResolver
      .getResources("s3://" + bucketName + "/*.xml");

  return Arrays.stream(resources).map(
      resource -> {
        try {
          return resource.getURL().toExternalForm();
        } catch (IOException e) {
          throw new RuntimeException(e);
        }
      }
  ).collect(Collectors.toList());
}

This code example as a project is pushed to my GitHub. You can find the project here.

Standard