pom.xml文件配置：我看官网SpringBoot的2.4.2版本与Spring Cloud的2020.0.0版本是对应的，服务端同样的版本是能正常启动的。
启动时报错如下：

2021-01-23 15:08:59.974  INFO 17952 --- [           main] com.imooc.client.ClientApplication       : Starting ClientApplication using Java 1.8.0_141 on Calvin with PID 17952 (D:\work\java\workspace\intellJ\imooc\spring_cloud_sell\client\target\classes started by 新哥 in D:\work\java\workspace\intellJ\imooc\spring_cloud_sell\client)
2021-01-23 15:08:59.977  INFO 17952 --- [           main] com.imooc.client.ClientApplication       : No active profile set, falling back to default profiles: default
2021-01-23 15:09:00.877  INFO 17952 --- [           main] o.s.cloud.context.scope.GenericScope     : BeanFactory id=49579535-20fd-33e2-9380-e39ad4187ca1
2021-01-23 15:09:05.170  WARN 17952 --- [           main] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration$RefreshableEurekaClientConfiguration': Unsatisfied dependency expressed through field 'optionalArgs'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.netflix.discovery.AbstractDiscoveryClientOptionalArgs<?>' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
2021-01-23 15:09:05.187  INFO 17952 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2021-01-23 15:09:05.218 ERROR 17952 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

Field optionalArgs in org.springframework.cloud.netflix.eureka.EurekaClientAutoConfiguration$RefreshableEurekaClientConfiguration required a bean of type 'com.netflix.discovery.AbstractDiscoveryClientOptionalArgs' that could not be found.

The injection point has the following annotations:
	- @org.springframework.beans.factory.annotation.Autowired(required=true)


Action:

Consider defining a bean of type 'com.netflix.discovery.AbstractDiscoveryClientOptionalArgs' in your configuration.


Process finished with exit code 1

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.2</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.imooc</groupId>
    <artifactId>client</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>client</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>2020.0.0</spring-cloud.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
        </repository>
    </repositories>

</project>

启动类.java

package com.imooc.client;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

@SpringBootApplication
@EnableDiscoveryClient
public class ClientApplication {

    public static void main(String[] args) {
        SpringApplication.run(ClientApplication.class, args);
    }

}

application.yml配置

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka
  instance:
    hostname: clientName
spring:
  application:
    name: client