使用R2DBC访问数据

<？xml版本=“ 1.0”编码=“ 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>
	<父母>
		<groupId> org.springframework.boot </ groupId>
		<artifactId> spring-boot-starter-parent </ artifactId>
		<version> 2.4.3 </ version>
		<relativePath /> <！-从存储库中查找父级->
	</ parent>
	<groupId> com.example </ groupId>
	<artifactId>访问数据r2dbc </ artifactId>
	<version> 0.0.1-SNAPSHOT </ version>
	<名称> accessing-data-r2dbc </名称>
	<description> Spring Boot的演示项目</ description>
	<属性>
		<java.version> 1.8 </java.version>
	</ properties>
	<依赖项>
		<依赖性>
			<groupId> org.springframework.boot </ groupId>
			<artifactId> spring-boot-starter-data-r2dbc </ artifactId>
		</ dependency>

		<依赖性>
			<groupId> com.h2database </ groupId>
			<artifactId> h2 </ artifactId>
			<scope>运行时</ scope>
		</ dependency>
		<依赖性>
			<groupId> io.r2dbc </ groupId>
			<artifactId> r2dbc-h2 </ artifactId>
			<scope>运行时</ scope>
		</ dependency>
		<依赖性>
			<groupId> org.springframework.boot </ groupId>
			<artifactId> spring-boot-starter-test </ artifactId>
			<scope>测试</ scope>
		</ dependency>
		<依赖性>
			<groupId> io.projectreactor </ groupId>
			<artifactId>反应器测试</ artifactId>
			<scope>测试</ scope>
		</ dependency>
	</ dependencies>

	<内部版本>
		<插件>
			<插件>
				<groupId> org.springframework.boot </ groupId>
				<artifactId> spring-boot-maven-plugin </ artifactId>
			</ plugin>
		</ plugins>
	</ build>

</ project>

插件{
	id'org.springframework.boot'版本'2.4.3'
	id'io.spring.dependency-management'版本'1.0.11.RELEASE'
	id'java'
}

组='com.example'
版本='0.0.1-SNAPSHOT'
sourceCompatibility ='1.8'

储存库{
	mavenCentral（）
}

依赖项{
	实现'org.springframework.boot：spring-boot-starter-data-r2dbc'
	runtime仅'com.h2database：h2'
	runtime仅'io.r2dbc：r2dbc-h2'
	testImplementation'org.springframework.boot：spring-boot-starter-test'
	testImplementation'io.projectreactor：reactor-test'
}

测试 {
	useJUnitPlatform（）
}

CREATE TABLE customer (id SERIAL PRIMARY KEY, first_name VARCHAR(255), last_name VARCHAR(255));

package com.example.accessingdatar2dbc;

import org.springframework.data.annotation.Id;

public class Customer {

    @Id
    private Long id;

    private final String firstName;

    private final String lastName;

    public Customer(String firstName, String lastName) {
        this.firstName = firstName;
        this.lastName = lastName;
    }

    public Long getId() {
        return this.id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getFirstName() {
        return this.firstName;
    }

    public String getLastName() {
        return this.lastName;
    }

    @Override
    public String toString() {
        return String.format(
            "Customer[id=%d, firstName='%s', lastName='%s']",
            id, firstName, lastName);
    }
}

package com.example.accessingdatar2dbc;

import org.springframework.data.r2dbc.repository.Query;
import org.springframework.data.repository.reactive.ReactiveCrudRepository;

import reactor.core.publisher.Flux;

public interface CustomerRepository extends ReactiveCrudRepository<Customer, Long> {

    @Query("SELECT * FROM customer WHERE last_name = :lastname")
    Flux<Customer> findByLastName(String lastName);

}

package com.example.accessingdatar2dbc;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class AccessingDataR2dbcApplication {

	public static void main(String[] args) {
		SpringApplication.run(AccessingDataR2dbcApplication.class, args);
	}

}

package com.example.accessingdatar2dbc;

import io.r2dbc.spi.ConnectionFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.r2dbc.connectionfactory.init.ConnectionFactoryInitializer;
import org.springframework.data.r2dbc.connectionfactory.init.ResourceDatabasePopulator;

import java.time.Duration;
import java.util.Arrays;

@SpringBootApplication
public class AccessingDataR2dbcApplication {

    private static final Logger log = LoggerFactory.getLogger(AccessingDataR2dbcApplication.class);

    public static void main(String[] args) {
        SpringApplication.run(AccessingDataR2dbcApplication.class, args);
    }

    @Bean
    ConnectionFactoryInitializer initializer(ConnectionFactory connectionFactory) {

        ConnectionFactoryInitializer initializer = new ConnectionFactoryInitializer();
        initializer.setConnectionFactory(connectionFactory);
        initializer.setDatabasePopulator(new ResourceDatabasePopulator(new ClassPathResource("schema.sql")));

        return initializer;
    }

    @Bean
    public CommandLineRunner demo(CustomerRepository repository) {

        return (args) -> {
            // save a few customers
            repository.saveAll(Arrays.asList(new Customer("Jack", "Bauer"),
                new Customer("Chloe", "O'Brian"),
                new Customer("Kim", "Bauer"),
                new Customer("David", "Palmer"),
                new Customer("Michelle", "Dessler")))
                .blockLast(Duration.ofSeconds(10));

            // fetch all customers
            log.info("Customers found with findAll():");
            log.info("-------------------------------");
            repository.findAll().doOnNext(customer -> {
                log.info(customer.toString());
            }).blockLast(Duration.ofSeconds(10));

            log.info("");

            // fetch an individual customer by ID
			repository.findById(1L).doOnNext(customer -> {
				log.info("Customer found with findById(1L):");
				log.info("--------------------------------");
				log.info(customer.toString());
				log.info("");
			}).block(Duration.ofSeconds(10));


            // fetch customers by last name
            log.info("Customer found with findByLastName('Bauer'):");
            log.info("--------------------------------------------");
            repository.findByLastName("Bauer").doOnNext(bauer -> {
                log.info(bauer.toString());
            }).blockLast(Duration.ofSeconds(10));;
            log.info("");
        };
    }

}

==使用findAll（）找到的客户：
Customer [id = 1，firstName ='Jack'，lastName ='Bauer']
客户[id = 2，firstName ='Chloe'，lastName ='O'Brian']
客户[id = 3，firstName ='Kim'，lastName ='Bauer']
Customer [id = 4，firstName ='David'，lastName ='Palmer']
Customer [id = 5，firstName ='Michelle'，lastName ='Dessler']

==找到findOne（1L）的客户：
Customer [id = 1，firstName ='Jack'，lastName ='Bauer']

==找到findByLastName（'Bauer'）的客户：
Customer [id = 1，firstName ='Jack'，lastName ='Bauer']
客户[id = 3，firstName ='Kim'，lastName ='Bauer']