SpringBoot整合 R2DBC

0、整合

1、导入R2DBC依赖

java 复制代码

    <!-- https://mvnrepository.com/artifact/io.asyncer/r2dbc-mysql -->
    <dependency>
        <groupId>io.asyncer</groupId>
        <artifactId>r2dbc-mysql</artifactId>
        <version>1.0.5</version>
    </dependency>
    <!--        响应式 Spring Data R2dbc-->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-data-r2dbc</artifactId>
    </dependency>

2、编写配置

XML 复制代码

spring:
  r2dbc:
    password: 123456
    username: root
    url: r2dbc:mysql://localhost:3306/test
    name: test

1、声明式接口：R2dbcRepository

Repository接口

java 复制代码

@Repository
public interface AuthorRepositories extends R2dbcRepository<TAuthor,Long> {

    //默认继承了一堆CRUD方法； 像mybatis-plus

    //QBC： Query By Criteria
    //QBE： Query By Example

    //成为一个起名工程师  where id In () and name like ?
    //仅限单表复杂条件查询
    Flux<TAuthor> findAllByIdInAndNameLike(Collection<Long> id, String name);

    //多表复杂查询

    @Query("select * from t_author") //自定义query注解，指定sql语句
    Flux<TAuthor> findHaha();


    // 1-1：关联
    // 1-N：关联
    //场景：
    // 1、一个图书有唯一作者； 1-1
    // 2、一个作者可以有很多图书： 1-N



}

java 复制代码

### 自定义Converter

```java
package com.atguigu.r2dbc.config.converter;

import com.atguigu.r2dbc.entity.TAuthor;
import com.atguigu.r2dbc.entity.TBook;
import io.r2dbc.spi.Row;
import org.springframework.core.convert.converter.Converter;
import org.springframework.data.convert.ReadingConverter;

import java.time.Instant;


@ReadingConverter //读取数据库数据的时候,把row转成 TBook
public class BookConverter implements Converter<Row, TBook> {
    @Override
    public TBook convert(Row source) {
        if(source == null) return null;
        //自定义结果集的封装
        TBook tBook = new TBook();

        tBook.setId(source.get("id", Long.class));
        tBook.setTitle(source.get("title", String.class));

        Long author_id = source.get("author_id", Long.class);
        tBook.setAuthorId(author_id);
        //        tBook.setPublishTime(source.get("publish_time", Instant.class));


        TAuthor tAuthor = new TAuthor();
        tAuthor.setId(author_id);
        tAuthor.setName(source.get("name", String.class));

        tBook.setAuthor(tAuthor);

        return null;
    }
}
```

### 配置生效

```java
@EnableR2dbcRepositories //开启 R2dbc 仓库功能；jpa
@Configuration
public class R2DbcConfiguration {


    @Bean //替换容器中原来的
    @ConditionalOnMissingBean
    public R2dbcCustomConversions conversions(){

        //把我们的转换器加入进去； 效果新增了我们的 Converter
        return R2dbcCustomConversions.of(MySqlDialect.INSTANCE,new BookConverter());
    }
}
```

## 2、编程式组件

- R2dbcEntityTemplate 
- DatabaseClient