Spring Cloud 是 Spring 旗下的一个顶级项目。

顶级项目啥意思？顶级项目用来干嘛的？为啥要分顶级不顶级？

谢谢老师。

老师以下的理解有问题吗：

       1、 集中式负载均衡：从下图中看出，每个服务器都有相同的服务，通过负载均衡来分配请求，避免出现：某个服务器一直响应而其他服务器空闲的情况。这样可以实现服务器减负载的效果。

     2、进程内负载均衡：

      图中第3步，如下语句，如果”application-service“这个服务对应很多provider，那ribbon就会从所有可用的provider中，根据负载均衡策略选择一个去链接。

怎么感觉体会不到区别呢。

老师，我这边接口serviceapi，provider01，provider02 都启动正常

2020-07-07 17:04:11.963 ERROR 15980 --- [nfoReplicator-0] c.n.d.s.t.d.RedirectingEurekaHttpClient  : Request execution error. endpoint=DefaultEndpoint{ serviceUrl='http://localhost:8085/eureka/}

com.sun.jersey.api.client.ClientHandlerException: java.net.ConnectException: Connection refused: connect

at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:187) ~[jersey-apache-client4-1.19.1.jar:1.19.1]

at com.sun.jersey.api.client.filter.GZIPContentEncodingFilter.handle(GZIPContentEncodingFilter.java:123) ~[jersey-client-1.19.1.jar:1.19.1]

at com.netflix.discovery.EurekaIdentityHeaderFilter.handle(EurekaIdentityHeaderFilter.java:27) ~[eureka-client-1.9.13.jar:1.9.13]

at com.sun.jersey.api.client.Client.handle(Client.java:652) ~[jersey-client-1.19.1.jar:1.19.1]

at com.sun.jersey.api.client.WebResource.handle(WebResource.java:682) ~[jersey-client-1.19.1.jar:1.19.1]

at com.sun.jersey.api.client.WebResource.access$200(WebResource.java:74) ~[jersey-client-1.19.1.jar:1.19.1]

at com.sun.jersey.api.client.WebResource$Builder.post(WebResource.java:570) ~[jersey-client-1.19.1.jar:1.19.1]

at com.netflix.discovery.shared.transport.jersey.AbstractJerseyEurekaHttpClient.register(AbstractJerseyEurekaHttpClient.java:56) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$1.execute(EurekaHttpClientDecorator.java:59) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.MetricsCollectingEurekaHttpClient.execute(MetricsCollectingEurekaHttpClient.java:73) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.register(EurekaHttpClientDecorator.java:56) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$1.execute(EurekaHttpClientDecorator.java:59) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.RedirectingEurekaHttpClient.executeOnNewServer(RedirectingEurekaHttpClient.java:118) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.RedirectingEurekaHttpClient.execute(RedirectingEurekaHttpClient.java:79) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.register(EurekaHttpClientDecorator.java:56) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$1.execute(EurekaHttpClientDecorator.java:59) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.RetryableEurekaHttpClient.execute(RetryableEurekaHttpClient.java:120) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.register(EurekaHttpClientDecorator.java:56) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$1.execute(EurekaHttpClientDecorator.java:59) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.SessionedEurekaHttpClient.execute(SessionedEurekaHttpClient.java:77) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.register(EurekaHttpClientDecorator.java:56) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.DiscoveryClient.register(DiscoveryClient.java:847) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.InstanceInfoReplicator.run(InstanceInfoReplicator.java:121) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.InstanceInfoReplicator$1.run(InstanceInfoReplicator.java:101) [eureka-client-1.9.13.jar:1.9.13]

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_231]

at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_231]

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_231]

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) [na:1.8.0_231]

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_231]

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_231]

at java.lang.Thread.run(Thread.java:748) [na:1.8.0_231]

Caused by: java.net.ConnectException: Connection refused: connect

at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) ~[na:1.8.0_231]

at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85) ~[na:1.8.0_231]

at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350) ~[na:1.8.0_231]

at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206) ~[na:1.8.0_231]

at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188) ~[na:1.8.0_231]

at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) ~[na:1.8.0_231]

at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) ~[na:1.8.0_231]

at java.net.Socket.connect(Socket.java:606) ~[na:1.8.0_231]

at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:121) ~[httpclient-4.5.10.jar:4.5.10]

at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:180) ~[httpclient-4.5.10.jar:4.5.10]

at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:144) ~[httpclient-4.5.10.jar:4.5.10]

at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:134) ~[httpclient-4.5.10.jar:4.5.10]

at org.apache.http.impl.client.DefaultRequestDirector.tryConnect(DefaultRequestDirector.java:605) ~[httpclient-4.5.10.jar:4.5.10]

at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:440) ~[httpclient-4.5.10.jar:4.5.10]

at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:835) ~[httpclient-4.5.10.jar:4.5.10]

at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:118) ~[httpclient-4.5.10.jar:4.5.10]

at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56) ~[httpclient-4.5.10.jar:4.5.10]

at com.sun.jersey.client.apache4.ApacheHttpClient4Handler.handle(ApacheHttpClient4Handler.java:173) ~[jersey-apache-client4-1.19.1.jar:1.19.1]

... 30 common frames omitted

2020-07-07 17:04:11.964  WARN 15980 --- [nfoReplicator-0] c.n.d.s.t.d.RetryableEurekaHttpClient    : Request execution failed with message: java.net.ConnectException: Connection refused: connect

2020-07-07 17:04:11.967  WARN 15980 --- [nfoReplicator-0] com.netflix.discovery.DiscoveryClient    : DiscoveryClient_CONSUMER-FEIGN/DESKTOP-8NIQN7P:consumer-feign:8083 - registration failed Cannot execute request on any known server

com.netflix.discovery.shared.transport.TransportException: Cannot execute request on any known server

at com.netflix.discovery.shared.transport.decorator.RetryableEurekaHttpClient.execute(RetryableEurekaHttpClient.java:112) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.register(EurekaHttpClientDecorator.java:56) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator$1.execute(EurekaHttpClientDecorator.java:59) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.SessionedEurekaHttpClient.execute(SessionedEurekaHttpClient.java:77) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.shared.transport.decorator.EurekaHttpClientDecorator.register(EurekaHttpClientDecorator.java:56) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.DiscoveryClient.register(DiscoveryClient.java:847) ~[eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.InstanceInfoReplicator.run(InstanceInfoReplicator.java:121) [eureka-client-1.9.13.jar:1.9.13]

at com.netflix.discovery.InstanceInfoReplicator$1.run(InstanceInfoReplicator.java:101) [eureka-client-1.9.13.jar:1.9.13]

at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_231]

at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_231]

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_231]

at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) [na:1.8.0_231]

at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_231]

at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_231]

at java.lang.Thread.run(Thread.java:748) [na:1.8.0_231]

没有hosts文件，是不是说明我的eureka注册失败了？

老师之前配置的eureka集群，是必须先启动的吧

老师你那个运行脚本能不能发一个给我，文档里的粘贴出来都是乱的。然后那个运行命令我也用不了，说是找不到命令，我用的是centOS 6.5 的版本

老师，请问我这个启动错误是什么原因呀，感觉都配置好了

老师麻烦你帮我看看这是什么问题，配置文件检查了几遍

老师您好：

这是我在gitee上面新建的配置文件：

eureka注册中心的配置文件：

# 端口号配置
server:
  port: 8080

# 配置应用名称
spring:
  application:
    name: eureka-server

eureka:
  client:
    fetch-registry: false
    register-with-eureka: false
    service-url:
      defaultZone: http://localhost:8080/eureka/

配置中心服务端的配置文件：

server:
  port: 8082

spring:
  application:
    name: config-server
  cloud:
    config:
      server:
        git:
          uri: https://gitee.com/vjxa/cloudconfig.git
          username: vjxa
          password: 密码

启动报错：

访问了springcloud默认的注册中心地址，但是我在服务端的配置文件里面加上eureka注册中心地址后可以正常访问：

server:
  port: 8082

spring:
  application:
    name: config-server
  cloud:
    config:
      server:
        git:
          uri: https://gitee.com/vjxa/cloudconfig.git
          username: vjxa
          password: 密码
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8080/eureka/

我在远程的仓库地址已经设置了注册中心的地址，在服务端还要设置一遍，这是为什么？

eureka集群搭建完，防火墙已经关闭，启动集群失败，错误信息如下

Ribbon 实现负载均衡的编码有两种方式：

1、通过在 RestTemplate 上配置注解 @LoadBalanced;

2、通过类 RibbonLoadBalancerClient 的 choose() 方法实现。我看资料上 RibbonLoadBalancerClient 这个类是可以自动注入的，并且我在测试类中也实现了自动注入的调用：

package cn.edu.hyit.test;

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest()
public class LoadBalanceTest {

    @Autowired
    RibbonLoadBalancerClient client;

    @Test
    public void test(){
        for (int i = 0; i < 10; i++) {
            ServiceInstance instance = this.client.choose("user-service");
            System.out.println(instance.getHost() + ":" + instance.getPort());
        }
    }
}

结果为：

但是当我在 controller 中对 RibbonLoadBalancerClient 这个类进行自动注入时，会报错，代码如下：

package cn.edu.hyit.user.controller;

import cn.edu.hyit.user.pojo.User;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("usercontroller")
@Slf4j
public class UserController {
    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private RibbonLoadBalancerClient ribbonLoadBalancerClient;

    @RequestMapping("findByIdByRibbon2/{id}")
    public User findByIdByRibbon2(@PathVariable("id") Integer id) {
        log.debug("findByIdByRibbon Method is Running...");

        ServiceInstance serviceInstance = ribbonLoadBalancerClient.choose("user-service");
        String url = "http://"+ serviceInstance.getHost() + ":" + serviceInstance.getPort() + "/usercontroller/" + id;
        System.out.println(url);
        User user = restTemplate.getForObject(url, User.class);
        return user;
    }
}

报错如下：

org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

at org.springframework.beans.factory.support.DefaultListableBeanFactory.raiseNoMatchingBeanFound(DefaultListableBeanFactory.java:1506) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1101) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1062) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:583) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:91) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:372) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1341) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:572) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:495) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:317) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:315) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:759) ~[spring-beans-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:869) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:550) ~[spring-context-5.0.8.RELEASE.jar:5.0.8.RELEASE]

at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) ~[spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]

at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:762) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]

at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:398) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:330) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:1258) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]

at org.springframework.boot.SpringApplication.run(SpringApplication.java:1246) [spring-boot-2.0.4.RELEASE.jar:2.0.4.RELEASE]

at cn.edu.hyit.ConsumerApplication.main(ConsumerApplication.java:14) [classes/:na]

2020-05-14 15:22:12.532 ERROR 13804 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************

APPLICATION FAILED TO START

***************************

Description:

Field ribbonLoadBalancerClient in cn.edu.hyit.user.controller.UserController required a bean of type 'org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient' that could not be found.

Action:

Consider defining a bean of type 'org.springframework.cloud.netflix.ribbon.RibbonLoadBalancerClient' in your configuration.

使用的 Spring Cloud 的版本为 Finchley.SR1。

请帮忙看看这个报错，谢谢！

问题解决了,重新打包了一下就好了..........................

搭建完成高可用集群后访问地址发现没有创建实例，host地址已经配置，防火墙已关

euerka server集群创建后不显示实例，防火墙已经关闭，Windows中hosts文件中已经添加虚拟机主机地址，euerka client端访问服务器显示找不到主机