使用 Spring mvc 和 spring webflux 而不使用 spring boot

Question

所以我有一个旧的工作应用程序，它使用 Spring MVC 而不是 spring boot。我在我的项目中添加了 spring-webflux 的 gradle 依赖项，并开始使用 webclient 从我的项目中调用外部 API。这是我的 webclient 处理程序类：

@Service
public class WebclientHandler {
    private final WebClient webClient;

    public WebclientHandler (WebClient.Builder builder) {
        this.webClient = builder.baseUrl("baseurl").build();
    }
}

现在，当我通过 API 调用此代码后，我收到此错误：

通过构造函数参数 0 表达的依赖关系不满足；嵌套异常是 org.springframework.beans.factory.NoSuchBeanDefinitionException：没有类型为“org.springframework.web.reactive.function.client.WebClient$Builder”的合格 bean 可用：预计至少有 1 个有资格作为自动装配候选者的 bean。依赖项注释：{}

似乎我的应用程序无法找到 Webclient.builder 并且不会发生构造函数注入。这是因为我没有使用 spring boot 吗？

这是我的 Gradle 依赖项：

compile(group: 'org.springframework', name: 'spring-webflux', version: '5.3.15')

我是 spring-webflux 反应式编程的新手。

编辑

我也尝试使用配置创建 Webclient bean：

 @Configuration
    public class WebClientHandler {
    
    @Bean
        public WebClient myWebClient() {
            WebClient client = WebClient.builder().baseUrl("baseUrl")
                    .defaultHeader(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
                    .defaultHeader(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON_VALUE)
                    .build();
            return client;
        }
}

现在我在启动时遇到此异常：

{ java.lang.IllegalStateException: No suitable default ClientHttpConnector found
    at org.springframework.web.reactive.function.client.DefaultWebClientBuilder.initConnector(DefaultWebClientBuilder.java:297)
    at org.springframework.web.reactive.function.client.DefaultWebClientBuilder.build(DefaultWebClientBuilder.java:266)
    at com.kronos.orgmap.sbs.impl.service.WebClientHandler.MyWebClient(WebClientHandler.java:41)
    at com.kronos.orgmap.sbs.impl.service.WebClientHandler$$EnhancerBySpringCGLIB$$59a9a582.CGLIB$desiWebClient$0(<generated>)
    at com.kronos.orgmap.sbs.impl.service.WebClientHandler$$EnhancerBySpringCGLIB$$59a9a582$$FastClassBySpringCGLIB$$76fa510d.invoke(<generated>)
    at org.springframework.cglib.proxy.MethodProxy.invokeSuper(MethodProxy.java:244)
    at org.springframework.context.annotation.ConfigurationClassEnhancer$BeanMethodInterceptor.intercept(ConfigurationClassEnhancer.java:331)
    at com.kronos.orgmap.sbs.impl.service.WebClientHandler$$EnhancerBySpringCGLIB$$59a9a582.MyWebClient(<generated>)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:154)
    at org.springframework.beans.factory.support.KronosConstructorResolver.instantiate(KronosConstructorResolver.java:654)
    at org.springframework.beans.factory.support.KronosConstructorResolver.instantiateUsingFactoryMethod(KronosConstructorResolver.java:487)
    at org.springframework.beans.factory.support.KronosAbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(KronosAbstractAutowireCapableBeanFactory.java:1345)
    at org.springframework.beans.factory.support.KronosAbstractAutowireCapableBeanFactory.createBeanInstance(KronosAbstractAutowireCapableBeanFactory.java:1193)
    at org.springframework.beans.factory.support.KronosAbstractAutowireCapableBeanFactory.doCreateBean(KronosAbstractAutowireCapableBeanFactory.java:611)
    at org.springframework.beans.factory.support.KronosAbstractAutowireCapableBeanFactory.createBean(KronosAbstractAutowireCapableBeanFactory.java:559)
    at org.springframework.beans.factory.support.KronosAbstractBeanFactory.lambda$doGetBean$0(KronosAbstractBeanFactory.java:336)
    at org.springframework.beans.factory.support.KronosDefaultSingletonBeanRegistry.getSingleton(KronosDefaultSingletonBeanRegistry.java:235)
    at org.springframework.beans.factory.support.KronosAbstractBeanFactory.doGetBean(KronosAbstractBeanFactory.java:334)
    at org.springframework.beans.factory.support.KronosAbstractBeanFactory.getBean(KronosAbstractBeanFactory.java:209)
    at org.springframework.beans.factory.support.KronosDefaultListableBeanFactory.preInstantiateSingletons(KronosDefaultListableBeanFactory.java:952)
    at com.kronos.container.impl.startup.KronosBeanFactory.preInstantiateSingletons(KronosBeanFactory.java:226)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:583)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:401)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:292)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:103)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4699)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5167)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
    at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:743)
    at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:719)
    at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:705)
    at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1125)
    at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1859)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
 } }

Answer 1

在我的 gradle 中添加这些依赖项为我解决了第二种方法的问题，现在 DefaultWebClientBuilder 能够启动由 webclient 构建器使用的连接器。

implementation platform('io.projectreactor:reactor-bom:2020.0.17')
    implementation 'io.projectreactor.netty:reactor-netty-core' 
    implementation 'io.projectreactor.netty:reactor-netty-http'

尽管仍然不明白为什么即使添加了提到的 gradle 依赖项后第一种方法也不起作用。仍然无法在构造函数中找到 WebClient.Builder 类作为 bean。

Answer 2

您只能使用“spring-boot-starter-webflux”：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-webflux</artifactId>
    <version>2.7.4</version>
</dependency>