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Spring-webflux访问关系型数据库实战

2023-07-09 11:05:40 作者：右耳菌

这篇文章主要为大家介绍了Spring-webflux访问关系型数据库实战详解，有需要的朋友可以借鉴参考下，希望能够有所帮助，祝大家多多进步，早日升职加薪

1. pom.xml引入

主要是支持在响应式的环境下对关系型数据库进行访问

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-r2dbc</artifactId>
        </dependency>
        <dependency>
            <groupId>com.github.jasync-sql</groupId>
            <artifactId>jasync-r2dbc-mysql</artifactId>
            <version>1.1.3</version>
        </dependency>

注意: 这里对于SpringBoot的版本似乎是有一些要求的，为了避免遇到无法正常启动的情况，建议使用版本2.3.0-RELEASE版本

完整的xml

<?xml version="1.0" encoding="UTF-8"?>
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>cn.lazyfennec</groupId>
    <artifactId>webflux-demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>webflux-demo</name>
    <description>Demo project for Spring Boot</description>
    <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>2.3.0.RELEASE</spring-boot.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </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>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-r2dbc</artifactId>
        </dependency>
        <dependency>
            <groupId>com.github.jasync-sql</groupId>
            <artifactId>jasync-r2dbc-mysql</artifactId>
            <version>1.1.3</version>
        </dependency>
    </dependencies>
    <!--  这里很重要，限定了SpringBoot的依赖版本  -->
    <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>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

2. 修改application.yml

spring:
  r2dbc:
    url: r2dbcs:mysql://localhost:3306/test
    username: root
    password: 123456

3. 创建实体类User

package cn.lazyfennec.webfluxdemo.model;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.annotation.Id;
import org.springframework.data.relational.core.mapping.Table;
/**
 * @Author: Neco
 * @Description:
 * @Date: create in 2022/7/25 23:15
 */
@Table("t_user")
@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {
    @Id
    private Long id;
    private String name;
}

4. 修改UserController

package cn.lazyfennec.webfluxdemo.controller;
import cn.lazyfennec.webfluxdemo.dao.UserDao;
import cn.lazyfennec.webfluxdemo.model.User;
import lombok.AllArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.*;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import java.util.stream.IntStream;
/**
 * @Author: Neco
 * @Description:
 * @Date: create in 2022/7/25 22:13
 */
@RestController
@Slf4j
@AllArgsConstructor
public class UserController {
    private final UserDao userDao;
    @GetMapping("user")
    public Flux<User> findAll(){
        return userDao.findAll();
    }
    @PostMapping("save")
    public Mono save(@RequestBody User user){
        return userDao.save(user);
    }
    @DeleteMapping("user/{id}")
    public Mono delete(@PathVariable Long id){
        return userDao.deleteById(id);
    }
    @GetMapping("user/{id}")
    public Mono findById(@PathVariable Long id){
        return userDao.findById(id);
    }
}

5. 启动类上方增加 @EnableR2dbcRepositories

package cn.lazyfennec.webfluxdemo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.r2dbc.repository.config.EnableR2dbcRepositories;
@SpringBootApplication
@EnableR2dbcRepositories // 必须新增这个
public class WebfluxDemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(WebfluxDemoApplication.class, args);
    }
}

6. 启动然后访问相关网址测试

其实除了以上的方式之外，还有另外的方式，即handler 和 router （路由的）方式

新增以下两个类

UserHandler

package cn.lazyfennec.webfluxdemo.handler;
import cn.lazyfennec.webfluxdemo.dao.UserDao;
import cn.lazyfennec.webfluxdemo.model.User;
import lombok.AllArgsConstructor;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.reactive.function.server.ServerResponse;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
/**
 * @Author: Neco
 * @Description:
 * @Date: create in 2022/7/26 0:25
 */
@Component
@AllArgsConstructor
public class UserHandler {
    private final UserDao userDao;
    //http://localhost:8080/save
    public Mono<ServerResponse> saveUser(ServerRequest request) {
        Mono<User> mono = request.bodyToMono(User.class);
        User user = mono.block();
        return ServerResponse.ok().build(userDao.save(user).then());
    }
    public Mono<ServerResponse> deleteUser(ServerRequest request) {
        Long id = Long.valueOf(request.pathVariable("id"));
        return ServerResponse.ok().build(userDao.deleteById(id).then());
    }
    public Mono<ServerResponse> getUserbyId(ServerRequest request) {
        Long id = Long.valueOf(request.pathVariable("id"));
        Mono<User> mono = userDao.findById(id);
        return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON).body(mono, User.class);
    }
    public Mono<ServerResponse> listUser(ServerRequest serverRequest) {
        Flux<User> userFlux = userDao.findAll();
        return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON).body(userFlux, User.class);
    }
}

UserRouter

package cn.lazyfennec.webfluxdemo.config;
import cn.lazyfennec.webfluxdemo.handler.UserHandler;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.web.reactive.function.server.RequestPredicates;
import org.springframework.web.reactive.function.server.RouterFunction;
import org.springframework.web.reactive.function.server.RouterFunctions;
import org.springframework.web.reactive.function.server.ServerResponse;
/**
 * @Author: Neco
 * @Description:
 * @Date: create in 2022/7/26 0:27
 */
@Configuration
public class UserRouter {
    @Bean
    public RouterFunction<ServerResponse> routUser(UserHandler userHandler) {
        return RouterFunctions
                .route(RequestPredicates.GET("/user")
                        .and(RequestPredicates.accept(MediaType.APPLICATION_JSON)), userHandler::listUser)
                .andRoute(RequestPredicates.GET("/user/{id}")
                        .and(RequestPredicates.accept(MediaType.APPLICATION_JSON)), userHandler::getUserbyId)
                .andRoute(RequestPredicates.DELETE("/user/{id}")
                        .and(RequestPredicates.accept(MediaType.APPLICATION_JSON)), userHandler::deleteUser);
    }
}

注释掉UserController

访问同样的内容

正常

Tips

官方并不建议使用mysql和webflux相结合，主要是事务方面会产生一定的问题。

关于webflux，在国内其实会使用到的几率并不是很大，所以大致了解一些简单的使用基本就可以了。

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