由于Reactor已经接管了 Java 世界,因此不可避免地会出现一个反应式 sql 库。在这篇博客中,我们将使用 r2dbc 和 h2 和 reactor。
可以在github上找到代码。
我们将从所需的依赖项开始。
<?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 http://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>2.5.2</version> </parent> <groupId>com.gkatzioura</groupId> <artifactId>r2dbc-reactor</artifactId> <version>1.0-SNAPSHOT</version> <properties> <maven.compiler.source>11</maven.compiler.source> <maven.compiler.target>11</maven.compiler.target> </properties> <dependencies> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-r2dbc</artifactId> </dependency> <dependency> <groupId>org.springframework.data</groupId> <artifactId>spring-data-commons</artifactId> </dependency> <dependency> <groupId>com.h2database</groupId> <artifactId>h2</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>io.r2dbc</groupId> <artifactId>r2dbc-h2</artifactId> <scope>runtime</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-test</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>io.projectreactor</groupId> <artifactId>reactor-test</artifactId> <scope>test</scope> </dependency> </dependencies> </project>
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我们从 r2dbc、h2 r2dbc 驱动程序、h2 二进制文件以及测试工具导入 spring 数据。
postgresql表结构:create table order_request ( id uuid NOT NULL constraint or_id_pk primary key, created_by varchar, created timestamp default now() not null, updated timestamp default now() not null );
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我们稍后会将其添加到 test/resources/schema.sql 以进行测试。
另外让我们添加一个新模型:
package com.gkatzioura.r2dbc.model; import java.time.LocalDateTime; import java.util.UUID; import org.springframework.data.annotation.Id; import org.springframework.data.domain.Persistable; import org.springframework.data.relational.core.mapping.Table; @Table("order_request") public class OrderRequest implements Persistable<UUID> { @Id private UUID id; private String createdBy; private LocalDateTime created; private LocalDateTime updated; public void setId(UUID id) { this.id = id; } public String getCreatedBy() { return createdBy; } public void setCreatedBy(String createdBy) { this.createdBy = createdBy; } public LocalDateTime getCreated() { return created; } public void setCreated(LocalDateTime created) { this.created = created; } public LocalDateTime getUpdated() { return updated; } public void setUpdated(LocalDateTime updated) { this.updated = updated; } @Override public UUID getId() { return id; } @Override public boolean isNew() { return created == null; } }
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注意isNew方法。通过这种方式,存储库可以确定对象是否应该被持久化或更新。
现在开始我们的存储库
package com.gkatzioura.r2dbc.repository; import java.util.UUID; import org.springframework.data.repository.reactive.ReactiveCrudRepository; import com.gkatzioura.r2dbc.model.OrderRequest; public interface OrderRepository extends ReactiveCrudRepository<OrderRequest, UUID> { }
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进行一些测试。
如上所述,上面的模式将驻留在 test/resources/schema.sql 中
我们将为测试 h2 db 添加一些配置。我们需要确保 h2 会选择 postgresql 接口。
package com.gkatzioura.r2dbc; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.core.io.ClassPathResource; import org.springframework.data.r2dbc.config.AbstractR2dbcConfiguration; import org.springframework.data.r2dbc.repository.config.EnableR2dbcRepositories; import org.springframework.r2dbc.connection.init.CompositeDatabasePopulator; import org.springframework.r2dbc.connection.init.ConnectionFactoryInitializer; import org.springframework.r2dbc.connection.init.ResourceDatabasePopulator; import io.r2dbc.h2.H2ConnectionFactory; import io.r2dbc.spi.ConnectionFactory; @Configuration @EnableR2dbcRepositories public class H2ConnectionConfiguration extends AbstractR2dbcConfiguration { @Override public ConnectionFactory connectionFactory() { return new H2ConnectionFactory( io.r2dbc.h2.H2ConnectionConfiguration.builder() .url("mem:testdb;MODE=PostgreSQL;DB_CLOSE_DELAY=-1;") .build() ); } @Bean public ConnectionFactoryInitializer initializer() { var initializer = new ConnectionFactoryInitializer(); initializer.setConnectionFactory(connectionFactory()); var databasePopulator = new CompositeDatabasePopulator(); databasePopulator.addPopulators(new ResourceDatabasePopulator(new ClassPathResource("schema.sql"))); initializer.setDatabasePopulator(databasePopulator); return initializer; } }
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通过此配置,我们创建了一个模拟 Postgresql 数据库的 H2 数据库,我们创建了模式并启用了 R2DBC 存储库的创建。
另外让我们添加一个测试。
package com.gkatzioura.r2dbc.repository; import java.util.UUID; import org.junit.jupiter.api.Test; import org.junit.jupiter.api.extension.ExtendWith; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.annotation.Import; import org.springframework.test.context.junit.jupiter.SpringExtension; import com.gkatzioura.r2dbc.H2ConnectionConfiguration; import com.gkatzioura.r2dbc.model.OrderRequest; import reactor.test.StepVerifier; @ExtendWith({SpringExtension.class}) @Import({H2ConnectionConfiguration.class}) class OrderRepositoryTest { @Autowired private OrderRepository orderRepository; @Test void testSave() { UUID id = UUID.randomUUID(); OrderRequest orderRequest = new OrderRequest(); orderRequest.setId(id); orderRequest.setCreatedBy("test-user"); var persisted = orderRepository.save(orderRequest) .map(a -> orderRepository.findById(a.getId())) .flatMap(a -> a.map(b -> b.getId())); StepVerifier.create(persisted).expectNext(id).verifyComplete(); } }
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