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Hernani Almeida
Hernani Almeida

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Desacoplando a camada de domínio de uma aplicação das outras camadas - parte 2

#java #simplesoftwarearchitecture #dynamodb #ddd

Ferramentas necessárias:

Vamos agora fazer a transição da nossa aplicação do banco de dados Postgres para DynamoDb, para isso precisamos adicionar as dependências referente ao DynamoDb e retirar as dependências referente ao Postgres em nosso arquivo pom.xml que devera ficar assim.
pom.xml

<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>2.6.6</version> <relativePath/> <!-- lookup parent from repository --> </parent> <groupId>com.example</groupId> <artifactId>ddd</artifactId> <version>0.0.1-SNAPSHOT</version> <name>ddd</name> <description>Demo project for Spring Boot</description> <properties> <java.version>11</java.version> </properties> <dependencyManagement> <dependencies> <dependency> <groupId>com.amazonaws</groupId> <artifactId>aws-java-sdk-bom</artifactId> <version>1.11.614</version> <type>pom</type> <scope>import</scope> </dependency> </dependencies> </dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-validation</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>com.github.derjust</groupId> <artifactId>spring-data-dynamodb</artifactId> <version>5.1.0</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> <configuration> <excludes> <exclude> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </exclude> </excludes> </configuration> </plugin> </plugins> </build> </project>
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Vamos modificar também nosso arquivo application.properties para deixar apenas o endpoint de acesso ao nosso banco de dados DynamoDb.
application.properties

server.error.include-message=always aws.amazonDynamoDBEndpoint=http://localhost:8000
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Rode o seguinte comando em seu terminal CMD para criar um banco de dados AWS/DynamoDb dentro de um container docker.

docker run -p 8000:8000 amazon/dynamodb-local -jar DynamoDBLocal.jar -inMemory -sharedDb

Vamos agora fazer a transição do armazenamento da nossa aplicação de Postgres para DynamoDb, para isso só precisaremos alterar nossa classe UsuarioAbstractRepositoryDB,mapear nossa tabela dynamoDb na classe Usuario e criar uma classe de configuração de acesso ao Aws/DynamoDb.
Dentro do package infrastructure crie um pakage config e dentro dele um package dynamodb, dentro do package dynamodb crie a classe de configuração DynamoDbConfig.
DynamoDbConfig

import com.amazonaws.client.builder.AwsClientBuilder; import com.amazonaws.services.dynamodbv2.AmazonDynamoDB; import com.amazonaws.services.dynamodbv2.AmazonDynamoDBClientBuilder; import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapper; import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBMapperConfig; import com.amazonaws.services.dynamodbv2.model.CreateTableRequest; import com.amazonaws.services.dynamodbv2.model.ProvisionedThroughput; import com.amazonaws.services.dynamodbv2.util.TableUtils; import com.example.ddd.core.usuario.Usuario; import org.springframework.beans.factory.annotation.Value; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration public class DynamoDbConfig { @Value(("${aws.amazonDynamoDBEndpoint}")) private String amazonDynamoDBEndpoint; @Bean public DynamoDBMapper dynamoDBMapper() { AmazonDynamoDB client = AmazonDynamoDBClientBuilder.standard() .withEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(amazonDynamoDBEndpoint, "us-west-2")) .build(); DynamoDBMapperConfig mapperConfig = DynamoDBMapperConfig.builder() .withSaveBehavior(DynamoDBMapperConfig.SaveBehavior.CLOBBER) .withConsistentReads(DynamoDBMapperConfig.ConsistentReads.CONSISTENT) .withTableNameOverride(null) .withPaginationLoadingStrategy(DynamoDBMapperConfig.PaginationLoadingStrategy.EAGER_LOADING) .build(); DynamoDBMapper dynamoDBMapper = new DynamoDBMapper(client, mapperConfig); init(dynamoDBMapper, client); return dynamoDBMapper; } public void init(DynamoDBMapper dynamoDBMapper, AmazonDynamoDB client) { CreateTableRequest tableRequest = dynamoDBMapper.generateCreateTableRequest(Usuario.class); tableRequest.setProvisionedThroughput(new ProvisionedThroughput(1L, 1L)); if (TableUtils.createTableIfNotExists(client, tableRequest)) { System.out.println("Table created"); } } }
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Altere a classe UsuarioAbstractRepositoryDB para métodos que irão acessar o dynamoDb e armazenar ou retornar os dados que precisamos.
UsuarioAbstractRepositoryDB

import java.util.List; @Repository public class UsuarioAbstractRepositoryDB { private DynamoDBMapper dynamoDBMapper; @Autowired public UsuarioAbstractRepositoryDB(DynamoDBMapper dynamoDBMapper) { this.dynamoDBMapper = dynamoDBMapper; } public Usuario buscaUsuarioPorId(String usuarioId) { return dynamoDBMapper.load(Usuario.class, usuarioId); } public List<Usuario> buscaUsuarios() { final DynamoDBScanExpression paginatedScanListExpression = new DynamoDBScanExpression(); final PaginatedScanList<Usuario> usuarioList = dynamoDBMapper.scan(Usuario.class, paginatedScanListExpression); return usuarioList; } public String deletaUsuario(String usuarioId){ Usuario usuario = dynamoDBMapper.load(Usuario.class,usuarioId); dynamoDBMapper.delete(usuario); return "Usuario deletado com sucesso"; } public Usuario criaUsuario(Usuario usuario) { dynamoDBMapper.save(usuario); return usuario; } public Usuario updateUsuario(String usuarioId, Usuario usuario) { dynamoDBMapper.save(usuario, new DynamoDBSaveExpression() .withExpectedEntry("usuarioId", new ExpectedAttributeValue( new AttributeValue().withS(usuarioId) ))); Usuario usuarioAtualizado = buscaUsuarioPorId(usuarioId); return usuarioAtualizado; } }
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Agora so precisamos mapear a criação da nossa entidade usuario dentro do banco de dados dynamoDb, para isso altere a classe Usuario da seguinte forma.
Usuario

import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBAttribute; import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBAutoGeneratedKey; import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBHashKey; import com.amazonaws.services.dynamodbv2.datamodeling.DynamoDBTable; @DynamoDBTable(tableName = "usuario") public class Usuario { @DynamoDBHashKey(attributeName = "usuarioId") @DynamoDBAutoGeneratedKey private String userId; @DynamoDBAttribute(attributeName = "name") private String name; @DynamoDBAttribute(attributeName = "email") private String email; @DynamoDBAttribute(attributeName = "cpf") private String cpf; @Deprecated public Usuario() { } public Usuario(String name, String email, String cpf) { this.name = name; this.email = email; this.cpf = cpf; } public String getUserId() { return userId; } public void setUserId(String userId) { this.userId = userId; } public String getName() { return name; } public String getEmail() { return email; } public String getCpf() { return cpf; } public void setName(String name) { this.name = name; } public void setEmail(String email) { this.email = email; } public void setCpf(String cpf) { this.cpf = cpf; } }
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E pronto, transição realizada sem precisar mexer na camada de domínio ou na camada de acesso externo de nossa aplicação, podemos rodar nossa aplicação e testar via Postman.

Usuario criado

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Lista Usuario

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Usuario Armazenado DynamoDB

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E isso ai galera, essa ultima parte deixarei no meu github para quem quiser acessar
Deixo aqui também meu linkedin para quem quiser me adicionar, grato a todos que leram este artigo e bora aprender galera.

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