java 简单的 DynamoDB 请求因 ResourceNotFoundException 而失败

Simple DynamoDB request failing with ResourceNotFoundException

提问by RTF

I'm just getting up and running with DynamoDB using the Java SDK (v1.8). I've created a very simple table using the AWS console. My table has a primary hash key, which is a String (no range). I've put a single item into the table with 4 other attribute values (all Strings).

我刚刚使用 Java SDK (v1.8) 启动并运行 DynamoDB。我使用 AWS 控制台创建了一个非常简单的表。我的表有一个主哈希键，它是一个字符串（无范围）。我已经将单个项目与 4 个其他属性值（所有字符串）一起放入表中。

I'm making a simple Java request for that item in the table, but it's failing with ResourceNotFoundException. I'm absolutely positive that the table name I'm supplying is correct, as is the name of the primary hash key that I'm using to query the item. The table status is listed in the AWS console as Activeand I can see the item and its values too.

我正在为表中的该项目发出一个简单的 Java 请求，但它失败了ResourceNotFoundException. 我绝对肯定我提供的表名是正确的，我用来查询项目的主哈希键的名称也是如此。表状态在 AWS 控制台中列为Active，我也可以看到该项目及其值。

This is the error I'm getting:

这是我得到的错误：

Requested resource not found (Service: AmazonDynamoDB; Status Code: 400; Error Code: ResourceNotFoundException; Request ID: ...)

I've tried the following (using the dynamodbv2versions of the classes):

我已经尝试了以下（使用dynamodbv2类的版本）：

Map<String, AttributeValue> key = new HashMap<String, AttributeValue>();
key.put(PRIMARY_KEY, new AttributeValue().withS(value));

GetItemRequest request = new GetItemRequest()
    .withTableName(TABLE_NAME)
    .withKey(key);

GetItemResult result = client.getItem(request);

I've also tried using the older, deprecated versions of all these classes, like this:

我还尝试使用所有这些类的旧的、已弃用的版本，如下所示：

GetItemRequest request = new GetItemRequest()
        .withTableName(TABLE_NAME)
        .withKey(new Key().withHashKeyElement(new AttributeValue().withS(value)));
GetItemResult result = client.getItem(request);

...but it's the same result.
My understanding of the ResourceNotFoundExceptionis that it means the table name or attribute referenced is invalid, which is not the case. It can also be thrown if the table is too early in the Creatingstate, but my table is Active.

……但结果是一样的。
我的理解ResourceNotFoundException是这意味着引用的表名或属性无效，事实并非如此。如果 table 在Creatingstate 中太早也可以抛出它，但是我的 table 是Active.

回答by RTF

The request was failing because I wasn't setting the region for the client before making the request. The default region is probably US East and my table is setup in EU West. This fixed it:

请求失败，因为我在发出请求之前没有为客户端设置区域。默认区域可能是美国东部，我的表设置在欧盟西部。这修复了它：

import com.amazonaws.regions.Region;
import com.amazonaws.regions.Regions;

client.setRegion(Region.getRegion(Regions.EU_WEST_1));

回答by gbk

the full code may looks like :

完整的代码可能如下所示：

import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;

import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClient;
import com.amazonaws.services.dynamodbv2.model.AttributeValue;
import com.amazonaws.services.dynamodbv2.model.ComparisonOperator;
import com.amazonaws.services.dynamodbv2.model.Condition;
import com.amazonaws.services.dynamodbv2.model.QueryRequest;
import com.amazonaws.services.dynamodbv2.model.QueryResult;

import com.amazonaws.regions.Region;
import com.amazonaws.regions.Regions;

public final class LogFetcher {

    static AmazonDynamoDBClient client = new AmazonDynamoDBClient();
    static String tableName = "<TABLE_NAME>";

    public static ArrayList<Object> findLogsForDeviceWithMacID(String macID) {

        client.setRegion(Region.getRegion(Regions.EU_WEST_1));

        Condition hashKeyCondition = new Condition()
                .withComparisonOperator(ComparisonOperator.EQ)
                .withAttributeValueList(new AttributeValue().withS(macID));
        Map<String, Condition> keyConditions = new HashMap<String, Condition>();
        keyConditions.put("parentKey", hashKeyCondition);

        QueryRequest queryRequest = new QueryRequest()
                .withTableName(tableName)
                .withKeyConditions(keyConditions);
        QueryResult result = client.query(queryRequest);

        ArrayList<Object> data = new ArrayList<Object>();

        for (Map<String, AttributeValue> item : result.getItems()) {
           // printItem(item);
            data.add(item);
        }
        return data;
    }

    private static void printItem(Map<String, AttributeValue> attributeList) {
        for (Map.Entry<String, AttributeValue> item : attributeList.entrySet()) {
            String attributeName = item.getKey();
            AttributeValue value = item.getValue();
            System.out.println(attributeName + " "
                    + (value.getS() == null ? "" : "S=[" + value.getS() + "]")
                    + (value.getN() == null ? "" : "N=[" + value.getN() + "]")
                    + (value.getB() == null ? "" : "B=[" + value.getB() + "]")
                    + (value.getSS() == null ? "" : "SS=[" + value.getSS() + "]")
                    + (value.getNS() == null ? "" : "NS=[" + value.getNS() + "]")
                    + (value.getBS() == null ? "" : "BS=[" + value.getBS() + "] \n"));
        }
    }
}

回答by sendon1982

If you use Spring Boot, then you can do like this:

如果你使用 Spring Boot，那么你可以这样做：

@Configuration
@EnableDynamoDBRepositories(basePackages = "com.test.repository")
@EntityScan("com.test.entity")
public class DynamoDBConfig {

    @Value("${amazon.dynamodb.endpoint}")
    private String amazonDynamoDBEndpoint;

    @Value("${amazon.aws.accesskey}")
    private String amazonAWSAccessKey;

    @Value("${amazon.aws.secretkey}")
    private String amazonAWSSecretKey;

@Bean
public AmazonDynamoDB amazonDynamoDB() {
    AwsClientBuilder.EndpointConfiguration endpointConfiguration = new AwsClientBuilder.EndpointConfiguration(
        amazonDynamoDBEndpoint, Regions.AP_SOUTHEAST_2.getName());

    AWSStaticCredentialsProvider credentialsProvider = new AWSStaticCredentialsProvider(amazonAWSCredentials());

    AmazonDynamoDB amazonDynamoDB = AmazonDynamoDBClientBuilder.standard().withEndpointConfiguration(
        endpointConfiguration).withCredentials(credentialsProvider).build();

    return amazonDynamoDB;
}

@Bean
public AWSCredentials amazonAWSCredentials() {
    return new BasicAWSCredentials(amazonAWSAccessKey, amazonAWSSecretKey);
}}