What is the difference between DynamoDBMapper and Table for DynamoDB Tables - amazon-web-services

Question

In AWS DynamoDB, There are two options available to do the CRUD operations on the Table.
DynamoDBMapper :
com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper;.
AmazonDynamoDB dbClient = AmazonDynamoDBAsyncClientBuilder.standard().withCredentials(creds)
.withRegion("us-east-1").build();
// creds is AWSCredentialsProvider
DynamoDBMapper mapper = new DynamoDBMapper(dbClient);
mapper.save(item);
Table: com.amazonaws.services.dynamodbv2.document.Table;.
static DynamoDB dynamoDB =new DynamoDB(dbClient);
Table table = dynamoDB.getTable("TABLE_NAME");
Item item =new Item().withPrimaryKey("","")
.withString("":, "");
table.putItem(item);
Both seem to do the same operations.
Is DynamoDBMapper a layer over Table? If so what are the differences in using each of these?

Answer 1

If you want to map Java classes to DynamoDB tables (which is a useful feature), consider moving away from the old V1 API (com.amazonaws.services.dynamodbv2 is V1). V2 packages are software.amazon.awssdk.services.dynamodb.*.
Replace this old API with the DynamoDB V2 Enhanced Client. You can learn about this here:
Map items in DynamoDB tables
You can find code examples for using the Enhanced Client here.
Here is a Java V2 code example that shows you how to use the Enhanced Client to put data into a Customer table. As you see, you can map a Java Class to columns in a DynamoDB table and then create a Customer object when adding data to the table.
package com.example.dynamodb;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbEnhancedClient;
import software.amazon.awssdk.enhanced.dynamodb.DynamoDbTable;
import software.amazon.awssdk.enhanced.dynamodb.TableSchema;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbSortKey;
import software.amazon.awssdk.regions.Region;
import software.amazon.awssdk.services.dynamodb.DynamoDbClient;
import software.amazon.awssdk.services.dynamodb.model.DynamoDbException;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbBean;
import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbPartitionKey;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
/*
* Prior to running this code example, create an Amazon DynamoDB table named Customer with a key named id and populate it with data.
* Also, ensure that you have setup your development environment, including your credentials.
*
* For information, see this documentation topic:
*
* https://docs.aws.amazon.com/sdk-for-java/latest/developer-guide/get-started.html
*/
public class EnhancedPutItem {
public static void main(String[] args) {
Region region = Region.US_EAST_1;
DynamoDbClient ddb = DynamoDbClient.builder()
.region(region)
.build();
DynamoDbEnhancedClient enhancedClient = DynamoDbEnhancedClient.builder()
.dynamoDbClient(ddb)
.build();
putRecord(enhancedClient) ;
ddb.close();
}
// Puts an item into a DynamoDB table
public static void putRecord(DynamoDbEnhancedClient enhancedClient) {
try {
DynamoDbTable<Customer> custTable = enhancedClient.table("Customer", TableSchema.fromBean(Customer.class));
// Create an Instant
LocalDate localDate = LocalDate.parse("2020-04-07");
LocalDateTime localDateTime = localDate.atStartOfDay();
Instant instant = localDateTime.toInstant(ZoneOffset.UTC);
// Populate the Table
Customer custRecord = new Customer();
custRecord.setCustName("Susan Blue");
custRecord.setId("id103");
custRecord.setEmail("sblue#noserver.com");
custRecord.setRegistrationDate(instant) ;
// Put the customer data into a DynamoDB table
custTable.putItem(custRecord);
} catch (DynamoDbException e) {
System.err.println(e.getMessage());
System.exit(1);
}
System.out.println("done");
}
#DynamoDbBean
public static class Customer {
private String id;
private String name;
private String email;
private Instant regDate;
#DynamoDbPartitionKey
public String getId() {
return this.id;
};
public void setId(String id) {
this.id = id;
}
#DynamoDbSortKey
public String getCustName() {
return this.name;
}
public void setCustName(String name) {
this.name = name;
}
public String getEmail() {
return this.email;
}
public void setEmail(String email) {
this.email = email;
}
public Instant getRegistrationDate() {
return regDate;
}
public void setRegistrationDate(Instant registrationDate) {
this.regDate = registrationDate;
}
}
}