SpringBoot2使用WebFlux函数式编程的方法

SpringBoot2使用WebFlux函数式编程的方法

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，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：

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

4.0.0

com.dalaoyang

springboot2_webflux

0.0.1-SNAPSHOT

jar

springboot2_webflux

springboot2_webflux

org.springframework.boot

spring-boot-starter-parent

2.0.3.RELEASE

UTF-8

UTF-8

1.8

org.springframework.boot

spring-boot-starter

org.springframework.boot

spring-boot-starter-test

test

org.springframework.boot

spring-boot-starter-webflux

org.springframework.boot

spring-boot-maven-plugin

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

4.0.0

com.dalaoyang

springboot2_webflux

0.0.1-SNAPSHOT

jar

springboot2_webflux

springboot2_webflux

org.springframework.boot

spring-boot-starter-parent

2.0.3.RELEASE

UTF-8

UTF-8

1.8

org.springframework.boot

spring-boot-starter

org.springframework.boot

spring-boot-starter-test

test

org.springframework.boot

spring-boot-starter-webflux

org.springframework.boot

spring-boot-maven-plugin

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

*/

@FDuHBqTBZeComponent

public class HiHandler {

public Mono 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 cookies();

Mono 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> messageWriters();

List viewResolvers();

}

public interface BodyBuilder extends ServerResponse.HeadersBuilder {

ServerResponse.BodyBuilder contentLength(long var1);

ServerResponse.BodyBuilder contentType(MediaType var1);

ServerResponse.BodyBuilder hint(String var1, Object var2);

> Mono body(P var1, Class var2);

> Mono body(P var1, ParameterizedTypeReference var2);

Mono syncBody(Object var1);

Mono body(BodyInserter, ? super ServerHttpResponse> var1);

Mono render(String var1, Object... var2);

Mono render(String var1, Map var2);

}

public interface HeadersBuilder> {

B header(String var1, String... var2);

B headers(Consumer var1);

B cookie(ResponseCookie var1);

B cookies(Consumer> var1);

B allow(HttpMethod... var1);

B allow(Set var1);

B eTag(String var1);

B lastModified(ZonedDateTime var1);

B location(URI var1);

B cacheControl(CacheControl var1);

B varyBy(String... var1);

Mono build();

Mono build(Publisher var1);

Mono build(BiFunction> 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 routeCity(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:

源码下载 ：大老杨码云

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