我试图品尝R2dbc并使用嵌入式H2，例如：

public ConnectionFactory connectionFactory() {
        //ConnectionFactory factory = ConnectionFactories.get("r2dbc:h2:mem:///test?options=DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE");
        return new H2ConnectionFactory(
                H2Connectionconfiguration.builder()
                        //.inmemory("testdb")
                        .file("./testdb")
                        .username("user")
                        .password("password").build()
        );
    }

然后我定义了一个bean以创建表和初始化数据。

@Bean
    public ConnectionFactoryInitializer initializer(ConnectionFactory connectionFactory) {

        ConnectionFactoryInitializer initializer = new ConnectionFactoryInitializer();
        initializer.setConnectionFactory(connectionFactory);

        CompositeDatabasePopulator populator = new CompositeDatabasePopulator();
        populator.addPopulators(new ResourceDatabasePopulator(new ClasspathResource("schema.sql")));
        populator.addPopulators(new ResourceDatabasePopulator(new ClasspathResource("data.sql")));
        initializer.setDatabasePopulator(populator);

        return initializer;
    }

我还定义了另一个组件，以通过Java代码设置数据。

@Component
@Slf4j
class DataInitializer {

    private final Databaseclient databaseclient;

    public DataInitializer(Databaseclient databaseclient) {
        this.databaseclient = databaseclient;
    }

    @EventListener(value = ContextRefreshedEvent.class)
    public void init() {
        log.info("start data initialization  ...");
        this.databaseclient.insert()
            .into("posts")
            //.nullValue("id",Integer.class)
            .value("title","First post title")
            .value("content","Content of my first post")
            .map((r,m) -> r.get("id",Integer.class))
            .all()
            .log()
            .thenmany(
                this.databaseclient.select()
                    .from("posts")
                    .orderBy(Sort.by(desc("id")))
                    .as(Post.class)
                    .fetch()
                    .all()
                    .log()
            )
            .subscribe(null,null,() -> log.info("initialization done..."));
    }

}

如果我在.inmemory("testdb") bean定义中使用ConnectionFactory，则在初始化Spring ApplicationContext时失败，因为找不到表POSTS 初始化DataInitializer时。通过启动日志记录，ConnectionFactoryInitializer已成功初始化，并创建表 POSTS 并通过执行schema.sql和data.sql按预期插入数据。

但是切换为使用.file("./testdb")确实有效。

完整的代码是here。