Get Multiple Items in DynamoDB Using Java (Guide w/ Code Examples)

To retrieve multiple items from a DynamoDB table in a single operation in Java, you can use the batchGetItem method of the AmazonDynamoDB client. In this example, YourTableName is the name of the table which you want to retrieve the items from.

The batchGetItem method accepts a BatchGetItemRequest object, which takes a map of the table name to KeysAndAttributes objects. Each KeysAndAttributes object represents the keys and attributes of the items that you want to retrieve.

import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder;
import com.amazonaws.services.dynamodbv2.model.KeysAndAttributes;
import com.amazonaws.services.dynamodbv2.model.batchGetItemRequest;
import com.amazonaws.services.dynamodbv2.model.Attributevalue;
import com.amazonaws.services.dynamodbv2.model.batchGetItemResult;

public class DynamoDBBatchGetExample {
    public static void main(String[] args) {
        AmazonDynamoDB client = AmazonDynamoDBClientBuilder.defaultClient();

        Map<String, KeysAndAttributes> requestItems = new HashMap<String, KeysAndAttributes>();

        List<Map<String, AttributeValue>> keys = new ArrayList<Map<String, AttributeValue>>();
        keys.add(new HashMap<String, AttributeValue>() {
            {
                put("id", new AttributeValue().withN("1"));
            }
        });
        keys.add(new HashMap<String, AttributeValue>() {
            {
                put("id", new AttributeValue().withN("2"));
            }
        });

        requestItems.put("YourTableName", new KeysAndAttributes().withKeys(keys));

        BatchGetItemRequest request = new BatchGetItemRequest()
                .withRequestItems(requestItems);

        BatchGetItemResult result = client.batchGetItem(request);

        System.out.println("Items retrieved successfully!");
        System.out.println(result.get());
    }
}