先说说什么是响应式
响应式编程或反应式编程（英语：Reactive programming）是一种面向数据流和变化传播的编程范式，直白的说就是：将变化的值通过数据流进行传播。
反应式架构文章
WebFlux是什么呢
WebFlux 模块的名称是 spring-webflux，名称中的 Flux 来源于 Reactor 中的类 Flux。Spring webflux 有一个全新的非堵塞的函数式 Reactive Web 框架，可以用来构建异步的、非堵塞的、事件驱动的服务，在伸缩性方面表现非常好。
spring-webflux 模块。该模块包含对响应式 HTTP 和 WebSocket 客户端的支持，以及对 REST，HTML 和 WebSocket 交互等程序的支持。一般来说，Spring MVC 用于同步处理，Spring Webflux 用于异步处理。
Spring Boot Webflux 有两种编程模型实现，一种类似 Spring MVC 注解方式，另一种是基于 Reactor 的响应式方式。
R2DBC是什么？
响应式关系数据库连接的支持
主题
之前我有对非关系性数据库的响应式api实现（传送门），而今天我们要说说非关系型数据库实现。
体验spring boot 2.3.0.RC1 , 期待已久mysql reactive 总算开始展露头角了。 今天就来整合一下springboot 和r2dbc 与mysql。主要是采用 Spring Data R2DBC ，Spring Data R2DBC对R2DBC应用了熟悉的Spring抽象和存储库支持。它使在响应式应用程序堆栈中构建使用关系数据访问技术的Spring驱动的应用程序更加容易。
POM
<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>com.gitee.occo</groupId>
<artifactId>occo-parent</artifactId>
<version>2.0.0-SNAPSHOT</version>
</parent>
<artifactId>occo-sso</artifactId>
<version>0.0.1-SNAPSHOT</version>
<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>dev.miku</groupId>
<artifactId>r2dbc-mysql</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
<exclusions>
<exclusion>
<groupId>org.junit.vintage</groupId>
<artifactId>junit-vintage-engine</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>io.projectreactor</groupId>
<artifactId>reactor-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>${java.version}</source>
<target>${java.version}</target>
<encoding>UTF-8</encoding>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-release-plugin</artifactId>
<configuration>
<tagNameFormat>v@{project.version}</tagNameFormat>
<autoVersionSubmodules>true</autoVersionSubmodules>
<indentSize>4</indentSize>
<useEditMode>true</useEditMode>
<localCheckout>true</localCheckout>
</configuration>
</plugin>
</plugins>
</build>
</project>
POM中的occo-parent可以替换成
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.0.RC1</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<!--下不了jar加上下面的：-->
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</pluginRepository>
</pluginRepositories>
application.yml
server:
port: 8000
spring:
application:
name: occo-sso
r2dbc:
url: r2dbc:mysql://localhost:3306/occo
username: root
password: pwd2020
logging:
level:
org.springframework.data.r2dbc: DEBUG
实现一个简单数据操作
repository：
import org.springframework.data.r2dbc.repository.Query;
import org.springframework.data.repository.reactive.ReactiveCrudRepository;
import org.springframework.stereotype.Repository;
import com.gitee.occo.sso.user.entity.User;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
@Repository
public interface UserRepository extends ReactiveCrudRepository<User, Long>{
@Query("SELECT * FROM user WHERE state = :state")
Flux<User> findByState(Integer state);
@Query("SELECT * FROM user WHERE username = :username")
Mono<User> findByUsername(String username);
@Query("SELECT * FROM user WHERE username LIKE :username")
Flux<User> findByUsernameLike(String username);
}
service
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.gitee.occo.sso.user.entity.User;
import com.gitee.occo.sso.user.repository.UserRepository;
import com.gitee.occo.sso.user.service.UserService;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
@Service
public class UserServiceImpl implements UserService {
@Autowired
private UserRepository userRepository;
@Override
public Mono<User> findById(Long id) {
// TODO Auto-generated method stub
return userRepository.findById(id);
}
@Override
public Mono<User> findByUsername(String username) {
// TODO Auto-generated method stub
return userRepository.findByUsername(username);
}
@Override
public Flux<User> findByUsernameLike(String username) {
// TODO Auto-generated method stub
return userRepository.findByUsernameLike(username);
}
}
controller:
import java.time.Duration;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.gitee.occo.sso.user.entity.User;
import com.gitee.occo.sso.user.service.UserService;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
@RestController
@RequestMapping("/user")
public class UserController {
@Autowired
UserService userService;
@GetMapping("/findById/{id}")
public Mono<User> getUserById(@PathVariable("id")Long id){
return userService.findById(id);
}
@GetMapping("/findByUsername")
public Mono<User> findByUsername(String username){
return userService.findByUsername(username);
}
@GetMapping(value="/findByUsernameLike" ,produces = MediaType.APPLICATION_STREAM_JSON_VALUE)
public Flux<User> getByUsername(String username){
return userService.findByUsernameLike(username+"%").delayElements(Duration.ofSeconds(2));
}
}
PS：produces = MediaType.APPLICATION_STREAM_JSON_VALUE 要加上，不然就会等待完成，一个请求体返回回去。
代码：传送门
