SpringCloud简单实例

骑猪看日落 2022-01-31 14:25 240阅读 0赞

## SpringCloud简单实例 ##

SpringCloud是基于SpringBoot，需要先了解SpringBoot的相关知识。

这里只是一个非常简单的包含注册表、服务提供者、服务消费者三者的例子。

源码见：  
[https://github.com/mengyuxiaofeng/SpringCloud][https_github.com_mengyuxiaofeng_SpringCloud]

**注册表如下**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MTcxMA_size_16_color_FFFFFF_t_70]

启动类

package demo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
    
    @SpringBootApplication
    @EnableEurekaServer    //声明这是一个Eureka服务器
    public class EurekaServerApplication {
    	public static void main(String[] args)
    	{
    		SpringApplication.run(EurekaServerApplication.class, args);//后面是直接设置端口号
    	}
    }

它的application.yml配置文件如下：（在resource文件下）

server:
      port: 8761    #声明端口号
    eureka:
      client:
        register-with-eureka: false    #默认是true，将自己注册到eureka上
        fetch-registry: false      #是否从eureka上获取信息，由于本案例是单机，无需从别的eureka上获取注册信息
        service-url:
          defaultZone: http://localhost:8761/eureka    #设置与eureka交互的地址，查询服务和注册服务都需要依赖这个地址，默认是：http://localhost:8761/eureka

它的pom.xml如下：

<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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.huoli.SpringCloudDemo</groupId>
      <artifactId>demo</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      
      <parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.6.RELEASE</version>
      </parent>
      
    
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Dalston.SR3</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement> 
    
      <dependencies>
        
        <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-jetty</artifactId>
        </dependency>
    
        <dependency>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-test</artifactId>
          <scope>test</scope>
        </dependency>
        
        
        <dependency>  
            <groupId>org.springframework.cloud</groupId>  
            <artifactId>spring-cloud-starter-eureka</artifactId>  
        </dependency>  
        <dependency>  
            <groupId>org.springframework.cloud</groupId>  
            <artifactId>spring-cloud-starter-eureka-server</artifactId>    
        </dependency>  
        
        <dependency>  
            <groupId>javax.servlet</groupId>  
            <artifactId>javax.servlet-api</artifactId>  
        </dependency>  
      </dependencies>
      
      <build>
        <plugins>
          <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
              <source>1.8</source>
              <target>1.8</target>
            </configuration>
          </plugin>
        </plugins>
      </build>
    </project>

启动刚开始的类EurekaServerApplication，在浏览器中有如下显示（刚开始是没有服务提供者的，这里是当服务提供者已经启动了才出现的）  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MTcxMA_size_16_color_FFFFFF_t_70 1]

**服务提供者如下：**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MTcxMA_size_16_color_FFFFFF_t_70 2]

启动类

package demo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
    
    @SpringBootApplication
    @EnableDiscoveryClient   //也可以用EnableDiscoveryClient代替，前者兼容性更大，后者仅能兼容Eureka
    public class ServerProvider {
    	public static void main(String[] args) {
            SpringApplication.run(ServerProvider.class, args);
        }
    }

controller类（注意和启动类的位置）

package demo;
    
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController  
    public class HelloController {  
        @RequestMapping("hello")  
        public String index() {  
            System.out.println("index is called");  
            return "Hello World";  
        }  
    }

application.yml文件

server:
      port: 8000
    
    spring:
      application:
        name: provider   #注册到Eureka Server上的应用名称
    eureka:
      client:
        service-url:
          defaultZone: http://localhost:8761/eureka    #注册的位置
      instance:
        prefer-ip-address: true  #将自己的ip注册到EuekaServer上

pom.xml文件和注册表的一样  
启动后，注册表的页面会有如下变化  
![在这里插入图片描述][20190516203902702.png]

**服务消费者（忽略掉User类）**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MTcxMA_size_16_color_FFFFFF_t_70 3]

启动类

package demo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.context.annotation.Bean;
    import org.springframework.web.client.RestTemplate;
    
    @SpringBootApplication
    public class ServerConsumer {
        
        @Bean
        public RestTemplate restTemplate() {
            return new RestTemplate();
        }
        public static void main(String[] args) {
            SpringApplication.run(ServerConsumer.class, args);
        }
    }

controller类（这也是我们需要在浏览器访问的）

package demo;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.client.RestTemplate;
    import demo.User;
    
    @RestController
    public class UserController {
        
        @Autowired
        private RestTemplate restTemplate;
        
        @GetMapping("/hello")
        public String getUser() {
            return this.restTemplate.getForObject("http://localhost:8000/hello", String.class);
        }
    }

pom.xml还是和注册表的一样（但是都要写）  
启动服务消费者，在浏览器中查看如下：

![在这里插入图片描述][2019051620394250.png]

[https_github.com_mengyuxiaofeng_SpringCloud]: https://github.com/mengyuxiaofeng/SpringCloud
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MTcxMA_size_16_color_FFFFFF_t_70]: /images/20220131/dc65012a4dc44f7792d61ee979c0229d.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MTcxMA_size_16_color_FFFFFF_t_70 1]: /images/20220131/beef59e5d4274c8a84939c3ec5e5161b.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MTcxMA_size_16_color_FFFFFF_t_70 2]: /images/20220131/9b530023af1844b7af04af7368032bb0.png
[20190516203902702.png]: /images/20220131/7bb1513bc89e4d719407e5c25282f323.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80Mzc1MTcxMA_size_16_color_FFFFFF_t_70 3]: /images/20220131/284083aa5ad448899c1de602151a7b3b.png
[2019051620394250.png]: /images/20220131/d5334c0fff4844f9aaf0b1327f19d124.png