In a previous post we used DynamoDBMapper in order to map DynamoDB Tables into Java objects.
When it comes to insert, our actions are pretty much the same but with a more convenient way. In order to insert an item all you have to do is to persist an object using the object mapper
In our case, we will create a User repository that does a simple insert.
package com.gkatzioura.dynamodb.mapper.repository;
import com.amazonaws.services.dynamodbv2.AmazonDynamoDB;
import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper;
import com.gkatzioura.dynamodb.mapper.entities.User;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
/**
* Created by gkatzioura on 9/22/16.
*/
public class UserMapperRepository {
private DynamoDBMapper dynamoDBMapper;
public UserMapperRepository(AmazonDynamoDB amazonDynamoDB) {
dynamoDBMapper = new DynamoDBMapper(amazonDynamoDB);
}
public void insert(User user) {
dynamoDBMapper.save(user);
}
}To persist we just have to create a simple object.
@Test
public void testInsertUser() {
User user = new User();
user.setRegisterDate(new Date().getTime());
user.setFullName("John Doe");
user.setEmail("john@doe.com");
userMapperRepository.insert(user);
}Also using DynamoDBMapper we can do batch inserts or batch deletes. Therefore we will add two extra methods to the repository.
public void insert(List<User> users) {
dynamoDBMapper.batchWrite(users,new ArrayList<>());
}
public void delete(List<User> users) {
dynamoDBMapper.batchDelete(users);
}Adding items in batch (or deleting) them, simply requires to pass a list of objects that contains values for the keys defined.
@Test
public void testBatchUserInsert() {
List<User> users = new ArrayList<>();
for(int i=0;i<10;i++) {
String email = emailPrefix+i+"@doe.com";
User user = new User();
user.setRegisterDate(new Date().getTime());
user.setFullName("John Doe");
user.setEmail("john@doe.com");
users.add(user);
}
userMapperRepository.insert(users);
}
@Test
public void testBatchDelete() {
testBatchUserInsert();
List<User> users = new ArrayList<>();
for(int i=0;i<10;i++) {
String email = emailPrefix+i+"@doe.com";
User user = new User();
user.setRegisterDate(new Date().getTime());
user.setFullName("John Doe");
user.setEmail("john@doe.com");
users.add(user);
}
userMapperRepository.delete(users);
}You can find the sourcecode on github
| Reference: | Insert DynamoDB Items with DynamoDBMapper from our JCG partner Emmanouil Gkatziouras at the gkatzioura blog. |
