Spring Cloud 概述及项目创建

Spring Cloud是一系列框架的有序集合，用于快速构建分布式系统的解决方案。它为服务发现，配置管理，断路器，智能路由，微代理，控制总线等操作提供了一种简单的开发方式。

创建Spring Cloud项目通常涉及以下步骤：

1. 创建一个Spring Boot项目。
2. 添加Spring Cloud依赖。
3. 配置Spring Cloud。

以下是一个简单的Spring Cloud项目创建示例：

<!-- pom.xml -->
<project ...>
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.1.RELEASE</version>
        <relativePath/>
    </parent>
 
    <groupId>com.example</groupId>
    <artifactId>demo-spring-cloud</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo-spring-cloud</name>
 
    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Hoxton.SR5</spring-cloud.version>
    </properties>
 
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </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>
 
</project>

// src/main/java/com/example/DemoSpringCloudApplication.java
package com.example;
 
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
 
@SpringBootApplication
@EnableDiscoveryClient
public class DemoSpringCloudApplication {
    public static void main(String[] args) {