spring cloud的入门级别的系统搭建

spring cloud是一套非常好的微服务架构解决方案，其原理和使用zookeeper及dubbo有些类似，将服务的生产者注册至服务中心，消费者去服务中心订阅该消费者，并进行消费，原理图如下：

系统背景：客户调用A系统获取数据，A系统需要将基本数据去B系统计算结果。

注册服务中心的搭建

1. 导入依赖（spring cloud是基于spring boot的，所以需要导入spring boot的依赖）：

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.4.RELEASE</version>
</parent>

<!-- 导入Spring Cloud的依赖管理 -->
<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>
    <!-- 导入Eureka服务的依赖 -->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-eureka-server</artifactId>
    </dependency>
    <!-- 注册服务中心设置登录权限 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-security</artifactId>
    </dependency>
</dependencies>

<build>
    <finalName>${project.artifactId}</finalName>
    <plugins>
        <!-- 资源文件拷贝插件 -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <configuration>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
        <!-- java编译插件 -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
    </plugins>
</build>

2.配置文件编写（application.yml）：

server:
  port: 6868 #服务端口

eureka:
  client:
    registerWithEureka: false #是否将自己注册到Eureka服务中，本身就是所有无需注册
    fetchRegistry: false #是否从Eureka中获取注册信息
    serviceUrl: #Eureka客户端与Eureka服务端进行交互的地址
      defaultZone: http://cloud:cloud@127.0.0.1:${server.port}/eureka/

security: 
  basic:  
    enable: true #开启基于HTTP basic的认证
  user: #配置用户的账号信息
    name: cloud
    password: cloud

3.启动类：

@EnableEurekaServer //申明这是一个Eureka服务
@SpringBootApplication
public class EurekaServer {

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

}

启动该服务，登录127.0.0.1:6868,进入注册服务中心控制台：

到此，注册中心就搭建完成，但是还没有服务注册。

计算系统的搭建

1.导入依赖

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.4.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-web</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-eureka-server</artifactId>
    </dependency>
</dependencies>

<build>
    <finalName>${project.artifactId}</finalName>
    <plugins>
        <!-- 资源文件拷贝插件 -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <configuration>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
        <!-- java编译插件 -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
    </plugins>
</build>

2.配置文件的编写

server:
  port: 8082

spring: 
  application:  
    name: com-spring-caclulate #指定服务名

eureka:
  client:
    registerWithEureka: true #是否将自己注册到Eureka服务中，默认为true
    fetchRegistry: true #是否从Eureka中获取注册信息，默认为true
    serviceUrl: #Eureka客户端与Eureka服务端进行交互的地址
      defaultZone: http://cloud:cloud@127.0.0.1:6868/eureka/
  instance: 
    prefer-ip-address: true #将自己的ip地址注册到Eureka服务中

3.启动类

@EnableDiscoveryClient//申请成为注册服务中心的客户端
@SpringBootApplication //申明这是一个Spring Boot项目
public class CacluApplication {

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

}

4.功能代码（系统中的业务代码）

@RestController
public class CacluController {

    /**
     * 对外提供接口服务，计算数据
     * 
     * @param num
     * @return
     */
    //@RequestMapping(method = RequestMethod.GET)
    @GetMapping(value = "caclu/{num}")
    public Integer caclulate(@PathVariable("num") Integer num) {
        return num*10;
    }
}

启动商品系统，再次登录注册服务中心，我们发现该服务已经注册了。

消费系统的搭建

1.导入依赖

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.4.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-web</artifactId>
    </dependency>
    <dependency>
        <groupId>com.squareup.okhttp3</groupId>
        <artifactId>okhttp</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-eureka-server</artifactId>
        <exclusions>
            <exclusion>
                <groupId>com.fasterxml.jackson.dataformat</groupId>
                <artifactId>jackson-dataformat-xml</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
</dependencies>

<build>
    <finalName>${project.artifactId}</finalName>
    <plugins>
        <!-- 资源文件拷贝插件 -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-resources-plugin</artifactId>
            <configuration>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
        <!-- java编译插件 -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
    </plugins>
</build>

2.配置文件

server:
  port: 8083

eureka:
  client:
    registerWithEureka: false #是否将自己注册到Eureka服务中，默认为true
    fetchRegistry: true #是否从Eureka中获取注册信息，默认为true
    serviceUrl: #Eureka客户端与Eureka服务端进行交互的地址
      defaultZone: http://cloud:cloud@127.0.0.1:6868/eureka/

3.启动类

@EnableDiscoveryClient
@SpringBootApplication
public class OrderApplication {

    @Bean // 向Spring容器中定义RestTemplate对象
    public RestTemplate restTemplate(){
        return new RestTemplate(new OkHttp3ClientHttpRequestFactory());

    }

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

4.业务代码

@RestController
public class OrderController {

    @Autowired
    private RestTemplate restTemplate;
    @Autowired
    private DiscoveryClient discoveryClient;


    @GetMapping(value = "query/result")
    public Integer caclulate() {
        String serviceId = "com-spring-caclulate";
        List<ServiceInstance> instances = this.discoveryClient.getInstances(serviceId);
        if(instances.isEmpty()){
            return null;
        }
        ServiceInstance serviceInstance = instances.get(0);
        String url = serviceInstance.getHost() + ":" + serviceInstance.getPort();
        return this.restTemplate.getForObject("http://" + url + "/caclu/1", Integer.class);
    }
}

启动服务，并访问接口，我们调用时num为1，计算结果为10。