从miku升级到asyncer r2dbc后，SpringBootTest遇DatabaseClient自动配置错误

问题描述 #

升级SpringBoot到2.7.10版本，同时从miku切换到io.asyncer:r2dbc-mysql:0.9.3依赖，运行带有@SpringBootTest和@AutoConfigureTestDatabase注解的测试时，触发如下错误：

No qualifying bean of type 'org.springframework.r2dbc.core.DatabaseClient' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {}

项目通过自定义配置类MySqlConnectionFactories继承AbstractR2dbcConfiguration创建ConnectionFactory，代码如下：

import io.r2dbc.spi.Option;
import io.asyncer.r2dbc.mysql.constant.SslMode;
import io.asyncer.r2dbc.mysql.constant.TlsVersions;
import io.r2dbc.spi.ConnectionFactories;
import io.r2dbc.spi.ConnectionFactory;
import io.r2dbc.spi.ConnectionFactoryOptions;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.r2dbc.config.AbstractR2dbcConfiguration;
import org.springframework.data.r2dbc.repository.config.EnableR2dbcRepositories;

@Configuration
@EnableR2dbcRepositories
public class MySqlConnectionFactories extends AbstractR2dbcConfiguration {
  
  @Value("${spring.datasource.host}")
  public String host;
  
  @Value("${spring.datasource.db}")
  public String db;
  
  @Value("${spring.datasource.username}")
  public String userName;

  @Value("${spring.datasource.password}")
  public String password;

  @Override
  @Bean
  public ConnectionFactory connectionFactory() {
    ConnectionFactoryOptions options = ConnectionFactoryOptions.builder()
        .option(ConnectionFactoryOptions.DRIVER, "mysql")
        .option(ConnectionFactoryOptions.HOST, host)
        .option(ConnectionFactoryOptions.USER, userName)
        .option(ConnectionFactoryOptions.PORT, 3306)
        .option(ConnectionFactoryOptions.PASSWORD, password)
        .option(ConnectionFactoryOptions.DATABASE, db)
        .option(Option.valueOf("sslMode"), SslMode.VERIFY_IDENTITY)
        .option(Option.valueOf("tlsVersion"), TlsVersions.TLS1_2)
        .option(Option.valueOf("useServerPrepareStatement"), true)
        .option(Option.valueOf("tcpKeepAlive"), true) // optional, default false
        .option(Option.valueOf("tcpNoDelay"), true) // optional, default false
        .build();
    return ConnectionFactories.get(options);
  }
}

当前依赖配置：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-r2dbc</artifactId>
</dependency>
<dependency>
    <groupId>io.asyncer</groupId>
    <artifactId>r2dbc-mysql</artifactId>
    <version>0.9.3</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-mongodb</artifactId>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
    <version>8.0.26</version>
</dependency>

解决方案 #

1. 排除JDBC测试自动配置干扰 #

@AutoConfigureTestDatabase默认针对JPA配置，会优先初始化JDBC测试数据库，导致R2DBC相关Bean的自动配置被跳过。可以通过两种方式解决：

• 若测试仅关注R2DBC组件，直接使用@R2dbcTest替代@SpringBootTest
• 保留@SpringBootTest，但排除JDBC相关自动配置并禁用测试数据库替换：

  @SpringBootTest(exclude = {DataSourceAutoConfiguration.class, DataSourceTransactionManagerAutoConfiguration.class})
  @AutoConfigureTestDatabase(replace = AutoConfigureTestDatabase.Replace.NONE)
  

2. 显式声明DatabaseClient Bean #

AbstractR2dbcConfiguration理论上会自动创建DatabaseClient，但如果自定义配置未触发该逻辑，可在配置类中手动添加：

@Bean
public DatabaseClient databaseClient(ConnectionFactory connectionFactory) {
    return DatabaseClient.create(connectionFactory);
}

3. 清理依赖并统一版本 #

• 移除mysql-connector-java依赖：R2DBC使用异步驱动，不需要JDBC连接器
• 去掉r2dbc-mysql的手动版本号，让Spring Boot依赖管理自动匹配兼容版本：

  <dependency>
      <groupId>io.asyncer</groupId>
      <artifactId>r2dbc-mysql</artifactId>
  </dependency>
  

4. 确保配置类被扫描 #

检查MySqlConnectionFactories所在包是否在Spring Boot组件扫描范围内，若不在测试类中可通过@Import(MySqlConnectionFactories.class)显式导入。

内容的提问来源于stack exchange，提问作者so_kirin