WebFlux/r2dbc/mysql增删改查Demo

环境和版本

• jdk1.8
• springboot 2.7.6
• idea

依赖

pom.xml部分内容：

<properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <spring-boot.version>2.7.6</spring-boot.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-r2dbc</artifactId>
        </dependency>
        <dependency>
            <groupId>io.asyncer</groupId>
            <artifactId>r2dbc-mysql</artifactId>
            <version>1.3.0</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>${spring-boot.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

配置

application.yml

spring:
  r2dbc:
    url: r2dbc:mysql://localhost:3306/r2dbc_demo?useServerPrepareStatement=true&useClientPrepareStatement=true&sslMode=DISABLED&serverZoneId=Asia/Shanghai
    username: root
    password: qk123
    pool:
      enabled: true
      initial-size: 1
      validation-query: select 1
  sql:
    init:
      mode: always
logging:
  level:
    com.example.demo.three: debug
server:
  port: 8080

模仿MybtisPlus的BaseMapper和Service

BaseRepository,java

package com.example.demo.three.base.repository;

import org.springframework.data.r2dbc.repository.R2dbcRepository;
import org.springframework.data.repository.reactive.ReactiveCrudRepository;

public interface BaseRepository<T, ID> extends ReactiveCrudRepository<T, ID>, R2dbcRepository<T, ID> {

}

IService.java

package com.example.demo.three.base.service;

import com.example.demo.three.base.repository.BaseRepository;
import reactor.core.publisher.Mono;


@SuppressWarnings("unchecked")
public interface IService<T, ID> {
    /**
     * 默认批次提交数量
     */
    int DEFAULT_BATCH_SIZE = 1000;

    /**
     * 插入一条记录（选择字段，策略插入）
     *
     * @param entity 实体对象
     */
    default Mono<T> save(T entity) {
        return getBaseRepository().save(entity);
    }

    /**
     * 根据 ID 删除
     *
     * @param id 主键ID
     */
    default Mono<Void> removeById(ID id) {
        return getBaseRepository().deleteById(id);
    }

    /**
     * 根据 ID 选择修改
     *
     * @param entity 实体对象
     */
    default Mono<T> updateById(T entity) {
        return getBaseRepository().save(entity);
    }

    default Mono<T> getById(ID id) {
        return getBaseRepository().findById(id);
    }


    BaseRepository<T, ID> getBaseRepository();

}

ServiceImpl.java

package com.example.demo.three.base.service.impl;

import com.example.demo.three.base.repository.BaseRepository;
import com.example.demo.three.base.service.IService;
import lombok.extern.slf4j.Slf4j;

import javax.annotation.Resource;

@Slf4j
public class ServiceImpl<R extends BaseRepository<T, ID>, T, ID> implements IService<T, ID> {

    @Resource
    private R baseRepository;

    @Override
    public BaseRepository<T, ID> getBaseRepository() {
        return baseRepository;
    }
}

配置扫描RepositoryRepositoryConfig .java

package com.example.demo.three.config;

import org.springframework.context.annotation.Configuration;
import org.springframework.data.r2dbc.repository.config.EnableR2dbcRepositories;

@Configuration
@EnableR2dbcRepositories("com.example.demo.three.repository")
public class RepositoryConfig {
}

创建一个实体类User.java

package com.example.demo.three.entity;

import lombok.AllArgsConstructor;
import lombok.Getter;
import lombok.NoArgsConstructor;
import lombok.Setter;
import lombok.experimental.Accessors;
import org.springframework.data.annotation.Id;
import org.springframework.data.relational.core.mapping.Column;
import org.springframework.data.relational.core.mapping.Table;

@Getter
@Setter
@Accessors(chain = true)
@AllArgsConstructor
@NoArgsConstructor
@Table("t_user")
public class User {
    @Id
    private Long id;
    @Column("name")
    private String name;
    @Column("username")
    private String username;
    @Column("password")
    private String password;
}

以及它的Repository、Service、Controller

UserRepository.java

package com.example.demo.three.repository;

import com.example.demo.three.base.repository.BaseRepository;
import com.example.demo.three.entity.User;
import org.springframework.stereotype.Repository;

@Repository
public interface UserRepository extends BaseRepository<User, Long> {

}

UserService.java

package com.example.demo.three.service;

import com.example.demo.three.base.service.IService;
import com.example.demo.three.entity.User;

public interface UserService extends IService<User, Long> {

}

UserServiceImpl.java

package com.example.demo.three.service;

import com.example.demo.three.base.service.impl.ServiceImpl;
import com.example.demo.three.entity.User;
import com.example.demo.three.repository.UserRepository;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl extends ServiceImpl<UserRepository, User, Long> implements UserService{

}

再加上接口UserController.java

package com.example.demo.three.controller;

import com.example.demo.three.entity.User;
import com.example.demo.three.service.UserService;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import reactor.core.publisher.Mono;

import javax.annotation.Resource;

@RestController
@RequestMapping("/user")
public class UserController {
    @Resource
    private UserService userService;

    /**
     * 新增用户
     * @param user 用户请求信息
     * @return 用户新增后信息
     */
    @PostMapping("/add")
    public Mono<User> add(@RequestBody User user){
        return userService.save(user);
    }

    /**
     * 根据id删除用户
     * @param id 用户id
     * @return 无
     */
    @DeleteMapping("/delete/{id}")
    public Mono<Void> deleteById(@PathVariable("id") Long id) {
        return userService.removeById(id);
    }

    /**
     * 根据id更新用户
     * @param user 用户信息
     * @return 新用户信息
     */
    @PutMapping("/update")
    public Mono<User> update(@RequestBody User user) {
        return userService.updateById(user);
    }

    /**
     * 根据id查询用户
     * @param id 用户id
     * @return 用户信息
     */
    @GetMapping("/get/{id}")
    public Mono<User> getById(@PathVariable("id") Long id) {
        return userService.getById(id);
    }

}

验证

启动服务，后调用新增接口。

新增成功，但是修改和删除都会报错。这个报错是提交事务之后报的，也就是会更改数据库。

经过定位，发现最终调用R2dbcEntityTemplate.doDelete方法，返回的是Mono<Integer>，但是驱动返回的是Long，导致不兼容。
有两个方法解决。
方法一：
升级jdk到17以上
方法二：
更换MySql驱动库

        <dependency>
            <groupId>dev.miku</groupId>
            <artifactId>r2dbc-mysql</artifactId>
            <version>0.8.2.RELEASE</version>
        </dependency>
        <!--  用这个驱动删除和修改会报类型转换异常      -->
<!--        <dependency>-->
<!--            <groupId>io.asyncer</groupId>-->
<!--            <artifactId>r2dbc-mysql</artifactId>-->
<!--            <version>1.3.0</version>-->
<!--        </dependency>-->