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SpringBoot2使用WebFlux函数式编程


本文只是简单使用SpringBoot2使用WebFlux的函数式编程简单使用,后续会继续写关于Webflux相关的文章。

最近一直在研究WebFlux,后续会陆续出一些相关的文章。

首先看一下Srping官网上的一张图,对比一下SpringMvc和Spring WebFlux,如图:

在查看一下WebFlux的官方文档:https://docs.spring.io/spring/docs/current/spring-framework-reference/web-reactive.html#spring-webflux,WebFlux提供了函数式编程,本文简单介绍一下WebFlux函数式编程简单使用。

新建项目

创建一个项目,pom文件中引入webflux依赖,完整pom文件如下:

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.dalaoyang</groupId>
    <artifactId>springboot2_webflux</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>springboot2_webflux</name>
    <description>springboot2_webflux</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.3.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-webflux</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

首先试试引入WebFlux依赖之后,SpringMvc方式是否还能使用,新建一个HelloController,完整代码如下,执行后发现,是可以正常执行访问的,这其实就是我们所说的注解式编程。

package com.dalaoyang.controller;

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * @author dalaoyang
 * @project springboot_learn
 * @package com.dalaoyang.controller
 * @email yangyang@dalaoyang.cn
 * @date 2018/7/30
 */
@RestController
public class HelloController {

    @GetMapping("hello")
    public String Hello(){
        return "Hello this is SpringWebFlux";
    }


}

结果如图:

接下来使用函数式编程,首先查阅一下官方文档,如图:

我们需要创建一个HandlerFunction返回值为Mono,新建一个HiHandler,里面写一个方法Hi,完整代码如下:

package com.dalaoyang.handler;
import org.springframework.http.MediaType;
import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.BodyInserters;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.reactive.function.server.ServerResponse;
import reactor.core.publisher.Mono;


/**
 * @author dalaoyang
 * @project springboot_learn
 * @package com.dalaoyang.handler
 * @email yangyang@dalaoyang.cn
 * @date 2018/7/30
 */
@Component
public class HiHandler {


    public Mono<ServerResponse> Hi(ServerRequest request) {
        return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON)
                .body(BodyInserters.fromObject("Hi , this is SpringWebFlux"));
    }
}

其中ServerResponse是相应的封装对象,下面是它的源码,其中包含了响应状态,响应头等等,代码如下:




package org.springframework.web.reactive.function.server; import java.net.URI; import java.time.ZonedDateTime; import java.util.List; import java.util.Map; import java.util.Set; import java.util.function.BiFunction; import java.util.function.Consumer; import org.reactivestreams.Publisher; import org.springframework.core.ParameterizedTypeReference; import org.springframework.http.CacheControl; import org.springframework.http.HttpHeaders; import org.springframework.http.HttpMethod; import org.springframework.http.HttpStatus; import org.springframework.http.MediaType; import org.springframework.http.ResponseCookie; import org.springframework.http.codec.HttpMessageWriter; import org.springframework.http.server.reactive.ServerHttpResponse; import org.springframework.util.MultiValueMap; import org.springframework.web.reactive.function.BodyInserter; import org.springframework.web.reactive.result.view.ViewResolver; import org.springframework.web.server.ServerWebExchange; import reactor.core.publisher.Mono; public interface ServerResponse { HttpStatus statusCode(); HttpHeaders headers(); MultiValueMap<String, ResponseCookie> cookies(); Mono<Void> writeTo(ServerWebExchange var1, ServerResponse.Context var2); static ServerResponse.BodyBuilder from(ServerResponse other) { return new DefaultServerResponseBuilder(other); } static ServerResponse.BodyBuilder status(HttpStatus status) { return new DefaultServerResponseBuilder(status); } static ServerResponse.BodyBuilder status(int status) { return new DefaultServerResponseBuilder(status); } static ServerResponse.BodyBuilder ok() { return status(HttpStatus.OK); } static ServerResponse.BodyBuilder created(URI location) { ServerResponse.BodyBuilder builder = status(HttpStatus.CREATED); return (ServerResponse.BodyBuilder)builder.location(location); } static ServerResponse.BodyBuilder accepted() { return status(HttpStatus.ACCEPTED); } static ServerResponse.HeadersBuilder<?> noContent() { return status(HttpStatus.NO_CONTENT); } static ServerResponse.BodyBuilder seeOther(URI location) { ServerResponse.BodyBuilder builder = status(HttpStatus.SEE_OTHER); return (ServerResponse.BodyBuilder)builder.location(location); } static ServerResponse.BodyBuilder temporaryRedirect(URI location) { ServerResponse.BodyBuilder builder = status(HttpStatus.TEMPORARY_REDIRECT); return (ServerResponse.BodyBuilder)builder.location(location); } static ServerResponse.BodyBuilder permanentRedirect(URI location) { ServerResponse.BodyBuilder builder = status(HttpStatus.PERMANENT_REDIRECT); return (ServerResponse.BodyBuilder)builder.location(location); } static ServerResponse.BodyBuilder badRequest() { return status(HttpStatus.BAD_REQUEST); } static ServerResponse.HeadersBuilder<?> notFound() { return status(HttpStatus.NOT_FOUND); } static ServerResponse.BodyBuilder unprocessableEntity() { return status(HttpStatus.UNPROCESSABLE_ENTITY); } public interface Context { List<HttpMessageWriter<?>> messageWriters(); List<ViewResolver> viewResolvers(); } public interface BodyBuilder extends ServerResponse.HeadersBuilder<ServerResponse.BodyBuilder> { ServerResponse.BodyBuilder contentLength(long var1); ServerResponse.BodyBuilder contentType(MediaType var1); ServerResponse.BodyBuilder hint(String var1, Object var2); <T, P extends Publisher<T>> Mono<ServerResponse> body(P var1, Class<T> var2); <T, P extends Publisher<T>> Mono<ServerResponse> body(P var1, ParameterizedTypeReference<T> var2); Mono<ServerResponse> syncBody(Object var1); Mono<ServerResponse> body(BodyInserter<?, ? super ServerHttpResponse> var1); Mono<ServerResponse> render(String var1, Object... var2); Mono<ServerResponse> render(String var1, Map<String, ?> var2); } public interface HeadersBuilder<B extends ServerResponse.HeadersBuilder<B>> { B header(String var1, String... var2); B headers(Consumer<HttpHeaders> var1); B cookie(ResponseCookie var1); B cookies(Consumer<MultiValueMap<String, ResponseCookie>> var1); B allow(HttpMethod... var1); B allow(Set<HttpMethod> var1); B eTag(String var1); B lastModified(ZonedDateTime var1); B location(URI var1); B cacheControl(CacheControl var1); B varyBy(String... var1); Mono<ServerResponse> build(); Mono<ServerResponse> build(Publisher<Void> var1); Mono<ServerResponse> build(BiFunction<ServerWebExchange, ServerResponse.Context, Mono<Void>> var1); } }

在回过头了看上面官方文档的图片,还需要配置一个路由来类似@RequestMapping的功能,通过RouterFunctions.route(RequestPredicate, HandlerFunction)提供了一个路由器函数默认实现,新建一个HiRouter,代码如下:

package com.dalaoyang.router;

import com.dalaoyang.handler.HiHandler;
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 dalaoyang
 * @project springboot_learn
 * @package com.dalaoyang.router
 * @email yangyang@dalaoyang.cn
 * @date 2018/7/30
 */
@Configuration
public class HiRouter {
    @Bean
    public RouterFunction<ServerResponse> routeHi(HiHandler hiHandler) {
        return RouterFunctions
                .route(RequestPredicates.GET("/hi")
                                .and(RequestPredicates.accept(MediaType.APPLICATION_JSON)),
                        hiHandler::Hi);
    }
}

启动项目,通过控制台可以看到,两种方式的映射都被打印出来了,如图所示:

在浏览器访问,http://localhost:8080/hi,结果如图所示:

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标签: SPRINGBOOT WEBFLUX