手把手带你创建微服务项目

**手把手带你创建微服务项目**

在软件开发领域，微服务（Microservices）是一种流行的架构模式，它将一个大型应用程序分解为多个小型独立的服务，每个服务都有自己的功能和数据模型。这种模式可以提高系统的可扩展性、灵活性和维护性。

在本文中，我们将手把手带你创建一个微服务项目，包括设计、开发和部署过程。

**步骤1：设计微服务**

首先，我们需要设计我们的微服务架构。我们将使用Eureka作为服务注册中心，Zuul作为API网关，Ribbon作为负载均衡器，Hystrix作为容错机制。

### 设计图

+---------------+
| Eureka |
+---------------+
 |
 |
 v+---------------+
| Zuul |
+---------------+
 |
 |
 v+---------------+
| Ribbon |
+---------------+
 |
 |
 v+---------------+
| Hystrix |
+---------------+

### 设计说明* Eureka：服务注册中心，负责管理和发现所有的微服务。
* Zuul：API网关，负责接收外部请求并转发给相应的微服务。
* Ribbon：负载均衡器，负责将请求分配到多个实例中，以实现负载均衡。
* Hystrix：容错机制，负责在某个服务不可用时提供fallback功能。

**步骤2：开发微服务**

接下来，我们需要开发我们的微服务。我们将使用Spring Boot作为开发框架。

###依赖项

xml<dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.cloud</groupId>
 <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.cloud</groupId>
 <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.cloud</groupId>
 <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.cloud</groupId>
 <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
 </dependency>
</dependencies>

###服务实现

java@SpringBootApplication@EnableEurekaClientpublic class MicroserviceApplication {
 public static void main(String[] args) {
 SpringApplication.run(MicroserviceApplication.class, args);
 }
}

@RestController@RequestMapping("/api")
public class MyController {
 @GetMapping("/hello")
 public String hello() {
 return "Hello World!";
 }
}

###服务注册

java@SpringBootApplication@EnableEurekaServerpublic class EurekaServerApplication {
 public static void main(String[] args) {
 SpringApplication.run(EurekaServerApplication.class, args);
 }
}

@Configurationpublic class EurekaConfig {
 @Bean public EurekaInstanceConfig eurekaInstanceConfig() {
 return new EmbeddedEurekaInstanceConfig();
 }

 @Bean public EurekaServer eurekaServer() {
 return new EurekaServer(eurekaInstanceConfig());
 }
}

### API网关

java@SpringBootApplication@EnableZuulProxypublic class ZuulApplication {
 public static void main(String[] args) {
 SpringApplication.run(ZuulApplication.class, args);
 }
}

@Configurationpublic class ZuulConfig {
 @Bean public ZuulFilter zuulFilter() {
 return new MyZuulFilter();
 }

 @Bean public FilterRegistrationBean filterRegistrationBean() {
 FilterRegistrationBean bean = new FilterRegistrationBean<>();
 bean.setFilter(zuulFilter());
 return bean;
 }
}

public class MyZuulFilter extends ZuulFilter {
 @Override public String filterName() {
 return "myFilter";
 }

 @Override public int filterOrder() {
 return0;
 }

 @Override public boolean shouldNotFilter() {
 return false;
 }

 @Override public Object run() {
 System.out.println("Hello World!");
 return null;
 }
}

### 负载均衡

java@SpringBootApplication@EnableRibbonClientpublic class RibbonApplication {
 public static void main(String[] args) {
 SpringApplication.run(RibbonApplication.class, args);
 }
}

@Configurationpublic class RibbonConfig {
 @Bean public IRule iRule() {
 return new RoundRobinRule();
 }

 @Bean public FilterRegistrationBean filterRegistrationBean() {
 FilterRegistrationBean bean = new FilterRegistrationBean<>();
 bean.setFilter(new MyZuulFilter());
 return bean;
 }
}

public class MyZuulFilter extends ZuulFilter {
 @Override public String filterName() {
 return "myFilter";
 }

 @Override public int filterOrder() {
 return0;
 }

 @Override public boolean shouldNotFilter() {
 return false;
 }

 @Override public Object run() {
 System.out.println("Hello World!");
 return null;
 }
}

### 容错机制

java@SpringBootApplication@EnableHystrixpublic class HystrixApplication {
 public static void main(String[] args) {
 SpringApplication.run(HystrixApplication.class, args);
 }
}

@Configurationpublic class HystrixConfig {
 @Bean public IExceptionThrower iExceptionThrower() {
 return new MyExceptionThrower();
 }

 @Bean public FilterRegistrationBean filterRegistrationBean() {
 FilterRegistrationBean bean = new FilterRegistrationBean<>();
 bean.setFilter(new MyZuulFilter());
 return bean;
 }
}

public class MyZuulFilter extends ZuulFilter {
 @Override public String filterName() {
 return "myFilter";
 }

 @Override public int filterOrder() {
 return0;
 }

 @Override public boolean shouldNotFilter() {
 return false;
 }

 @Override public Object run() {
 System.out.println("Hello World!");
 return null;
 }
}

public class MyExceptionThrower implements IExceptionThrower {
 @Override public void throwException() {
 throw new RuntimeException();
 }
}

**步骤3：部署微服务**

最后，我们需要部署我们的微服务。我们将使用Docker作为容器运行环境。

### Dockerfile

dockerfileFROM openjdk:8-jdk-alpineWORKDIR /appCOPY . /app/

RUN mvn clean packageEXPOSE8080CMD ["java", "-jar", "microservice.jar"]

### docker-compose.yml

ymlversion: '3'

services:
 eureka-server:
 image: eurekaserver ports:
 - "8761:8761"
 depends_on:
 - zuul-server environment:
 - SPRING_PROFILES_ACTIVE=dev zuul-server:
 image: zuulserver ports:
 - "8080:8080"
 depends_on:
 - eureka-server environment:
 - SPRING_PROFILES_ACTIVE=dev ribbon-client:
 image: ribbonclient ports:
 - "8090:8090"
 depends_on:
 - zuul-server environment:
 - SPRING_PROFILES_ACTIVE=dev hystrix-server:
 image: hystrixxserver ports:
 - "8081:8081"
 depends_on:
 - eureka-server environment:
 - SPRING_PROFILES_ACTIVE=dev

### docker-compose up

bashdocker-compose up --build

在本文中，我们手把手带你创建了一个微服务项目，包括设计、开发和部署过程。我们使用Eureka作为服务注册中心，Zuul作为API网关，Ribbon作为负载均衡器，Hystrix作为容错机制。我们使用Spring Boot作为开发框架，并且使用Docker作为容器运行环境。

希望本文对你有所帮助！