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Insert DynamoDB Items With DynamoDBMapper

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Insert DynamoDB Items With DynamoDBMapper

As we continue our series, once you've mapped your tables into Java objects, it's then time to insert them. Learn how to do that here.

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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 source code on GitHub.

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Topics:
database ,dynamodb ,aws ,java

Published at DZone with permission of Emmanouil Gkatziouras, DZone MVB. See the original article here.

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