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:，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：

    
        
     
      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
                    
               
          
     
    复制代码

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 */@RestControllerpublic class HelloController {    @GetMapping("hello")    public String Hello(){        return "Hello this is SpringWebFlux";    }}复制代码

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 */@Componentpublic class HiHandler {    public Mono
    
      Hi(ServerRequest request) {        return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON)                .body(BodyInserters.fromObject("Hi , this is SpringWebFlux"));    }}复制代码
    

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
                  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); }}复制代码
                             
                            
                           
                          
                         
                        
                       
                      
                     
                   
                  
                 
                
               
              
             
            
           
          
         
        
       
      
     
    

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 */@Configurationpublic class HiRouter {    @Bean    public RouterFunction
    
      routeHi(HiHandler hiHandler) {        return RouterFunctions                .route(RequestPredicates.GET("/hi")                                .and(RequestPredicates.accept(MediaType.APPLICATION_JSON)),                        hiHandler::Hi);    }}复制代码
    

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，,结果如图所示:

源码下载 ：

个人网站：

关注作者公众号