Dynamodb RequestHandler的验收规范验收规范、Dynamodb、RequestHandler
我在云中运行发电机插入时，任何帮助或线索，如何调试这样的错误发现了一个神秘的异常？
背景
在code我运行：
成功与数据插入dynamodb从我的本地机器上运行的时候，但
在云中过EMR硕士学位preduce作业运行失败时突然因身份验证。
用于认证的URL端点。
我简单地创建一个像这样的凭据：
客户端=新DynamoDBClient（新BasicAWSCredentials（
XXXX，
XXXXXXXXXXX））;
client.setEndpoint（https://dynamodb.eu-west-1.amazonaws.com）;
的异常即时得到如下：
在线程异常主要java.lang.NoSuchFieldError：requestHandlers
在com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient.init(AWSSecurityTokenServiceClient.java:214)
在com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient.<init>(AWSSecurityTokenServiceClient.java:160)
在com.amazonaws.auth.STSSessionCredentialsProvider＆LT; INIT＆GT;（STSSessionCredentialsProvider.java:73）
在com.amazonaws.auth.SessionCredentialsProviderFactory.getSessionCredentialsProvider(SessionCredentialsProviderFactory.java:96)
在com.amazonaws.services.dynamodb.AmazonDynamoDBClient.setEndpoint（AmazonDynamoDBClient.java:857）
在com.amazonaws.services.dynamodb.AmazonDynamoDBClient.init（AmazonDynamoDBClient.java:262）
在com.amazonaws.services.dynamodb.AmazonDynamoDBClient＆LT; INIT＆GT;（AmazonDynamoDBClient.java:181）
在com.amazonaws.services.dynamodb.AmazonDynamoDBClient＆LT; INIT＆GT;（AmazonDynamoDBClient.java:142）
解决方案
真实的答案在这里，是，dynamodb客户不与最新的或当前版本匹配可以呈现出奇怪的反射/类加载错误时我们尝试使用他们在一个现代化的环境。
在AWS罐子在旧EMR AMI实例的类路径可以使用它调用非EMR服务的Hadoop作业正确（最新）AWS罐存在冲突（即如dynamodb，在我们的例子）。
在我的旧AMI实例，我只是发：
MV $ HOME / lib目录/ AWS-java的SDK-1.1.1.jar $ HOME / lib目录/ AWS-java的SDK-1.1.1.jar.old
要在单节点群集上解决这个问题。
此错误的根本原因是什么？是，我使用的是较旧的红宝石弹性-MA preduce客户端，从而导致创建旧的AMI版本在我的电子病历云，这对类路径过时的AWS-SDK罐子。
I have found a cryptic exception when running dynamo inserts in the cloud, any help or clues as to how to debug such an error ?
Background
The code I am running :
Succesfully inserts data into dynamodb when run from my local machines, but
Fails abruptly due to authentication when running in the cloud in a mapreduce job over EMR.
Uses a URL endpoint for authentication.
I simply create credentials like so:
client=new DynamoDBClient(new BasicAWSCredentials(
"XXXX",
"XXXXXXXXXXX));
client.setEndpoint("https://dynamodb.eu-west-1.amazonaws.com");
The exception Im getting is below:
Exception in thread "main" java.lang.NoSuchFieldError: requestHandlers
at com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient.init(AWSSecurityTokenServiceClient.java:214)
at com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClient.<init>(AWSSecurityTokenServiceClient.java:160)
at com.amazonaws.auth.STSSessionCredentialsProvider.<init>(STSSessionCredentialsProvider.java:73)
at com.amazonaws.auth.SessionCredentialsProviderFactory.getSessionCredentialsProvider(SessionCredentialsProviderFactory.java:96)
at com.amazonaws.services.dynamodb.AmazonDynamoDBClient.setEndpoint(AmazonDynamoDBClient.java:857)
at com.amazonaws.services.dynamodb.AmazonDynamoDBClient.init(AmazonDynamoDBClient.java:262)
at com.amazonaws.services.dynamodb.AmazonDynamoDBClient.<init>(AmazonDynamoDBClient.java:181)
at com.amazonaws.services.dynamodb.AmazonDynamoDBClient.<init>(AmazonDynamoDBClient.java:142)
解决方案
The "real" answer here, is that, dynamodb clients which don't match up with the latest or current versions can exhibit odd reflection / class loading error when we attempt to use them in a modern environment.
AWS jars exist on the class path of older EMR AMI instances can conflict with proper (latest) AWS jars used by hadoop job which invokes a non-EMR service (i.e. such as dynamodb, in our case).On my older AMI instance, I simply issued:
mv $HOME/lib/aws-java-sdk-1.1.1.jar $HOME/lib/aws-java-sdk-1.1.1.jar.old
To resolve the issue on a single node cluster.
The ROOT cause of this error? was that I was using an older Ruby elastic-mapreduce client, which led to creation of older AMI versions in my EMR cloud, which had obsolete aws-sdk jars on the class path.
