缺少spring-cloud-starter-ribbon的HTTP客户端依赖项

我有一个简单的Spring Boot应用程序,它有一个简单的REST客户端,看起来像这样：

@Service
public class MyRestClient {

  private static final String url = "http://localhost:8080/";

  private RestTemplate restTemplate;

  @Autowired
  public MyRestClient(RestTemplate restTemplate) {
    this.restTemplate = restTemplate;
  }

  public String invoke() {
    return restTemplate.getForObject(url, String.class);
  }
}

这与Spring Boot完美配合.

现在我正在尝试将Spring Cloud添加到项目中以使Ribbon Client负载平衡.我按照这里的链接：

https://spring.io/guides/gs/client-side-load-balancing/

或者这里,这似乎是复制和粘贴,但有更多的更新依赖：

http://www.baeldung.com/spring-cloud-rest-client-with-netflix-ribbon

即使没有向MyRestClient添加任何注释,我添加以下内容的那一刻：

<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
<version>1.3.4.RELEASE</version>
</dependency>

我得到以下异常：

 Caused by: org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.client.RestTemplate]: Factory method 'restTemplate' threw exception; nested exception is java.lang.NoClassDefFoundError: org/apache/http/impl/client/HttpClients
        at org.springframework.beans.factory.support.SimpleInstantiationStrategy.instantiate(SimpleInstantiationStrategy.java:189) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
        at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:588) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
        ... 31 common frames omitted
    Caused by: java.lang.NoClassDefFoundError: org/apache/http/impl/client/HttpClients
        at org.springframework.http.client.HttpComponentsClientHttpRequestFactory.<init>(HttpComponentsClientHttpRequestFactory.java:88) ~[spring-web-4.3.11.RELEASE.jar:4.3.11.RELEASE]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_131]
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_131]
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_131]
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_131]
        at java.lang.Class.newInstance(Class.java:442) ~[na:1.8.0_131]
        at org.springframework.beans.BeanUtils.instantiate(BeanUtils.java:77) ~[spring-beans-4.3.11.RELEASE.jar:4.3.11.RELEASE]
        at org.springframework.boot.web.client.RestTemplateBuilder.detectRequestFactory(RestTemplateBuilder.java:596) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
        at org.springframework.boot.web.client.RestTemplateBuilder.configureRequestFactory(RestTemplateBuilder.java:559) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
        at org.springframework.boot.web.client.RestTemplateBuilder.configure(RestTemplateBuilder.java:527) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
        at org.springframework.boot.web.client.RestTemplateBuilder.build(RestTemplateBuilder.java:515) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]
        at org.springframework.boot.web.client.RestTemplateBuilder.build(RestTemplateBuilder.java:501) ~[spring-boot-1.5.7.RELEASE.jar:1.5.7.RELEASE]

为什么我的REST客户端在没有这种依赖关系的情况下工作,但是在没有添加任何注释或任何内容的情况下,我添加此依赖项的那一刻,我得到这个异常？

我试图在文档或示例中添加各种依赖项,例如spring-cloud-dependencies(看起来已被弃用),spring-cloud-netflix等无济于事.

添加什么才能使其正常工作？

解决方法:

看起来像this forum post中的问题和HttpClients所需的依赖关系是org.apache.httpcomponents/httpclient,版本至少为4.3.3.

标签：rest,spring,spring-boot-2,spring-cloud-2,spring-cloud-netflix
来源： https://codeday.me/bug/20190527/1163298.html