微服务搭建

工程初始化

1. 新建一个空的父工程，也可以创建maven项目
   
2. 创建子模块
   

注册中心子模块

1. pom.xml

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.cloud.demo</groupId>
    <artifactId>eureka</artifactId>
    <version>1.0-SNAPSHOT</version>

    <name>eureka</name>
    <!-- FIXME change it to the project's website -->
    <url>http://www.example.com</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <maven.compiler.source>1.7</maven.compiler.source>
        <maven.compiler.target>1.7</maven.compiler.target>
    </properties>

    <!--引入springboot-parent父项目-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.7.RELEASE</version>
    </parent>

    <dependencies>
        <!--引入springcloud的euekea server依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

    </dependencies>


    <!--指定下载源和使用springcloud的版本-->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.SR5</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

2. 配置

server:
  port: 9000 # 端口自己决定
#指定当前eureka客户端的注册地址，也就是eureka服务的提供方，当前配置的服务的注册服务方
eureka:
  client:
    service-url:
      defaultZone: http://${eureka.instance.hostname}:9000/eureka
    register-with-eureka: false #自身 不再向eureka注册
    fetch-registry: false  #启动时禁用client的注册
  instance:
    hostname: localhost

#指定应用名称
spring:
  application:
    name: eureka-server

3. 启动类

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

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

4. 启动
   

提供服务的客户端子模块

1. pom.xml

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>provider</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.7.RELEASE</version>
    </parent>
<dependencies>
    <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-openfeign</artifactId>
    </dependency>
</dependencies>

    <!--指定下载源和使用springcloud的版本-->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.SR5</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

2. 写一个简单的接口和实现类

public interface ProviderDemoService {
    String sayHello();
}

import com.cloud.provider.service.ProviderDemoService;
import org.springframework.stereotype.Service;

@Service
public class ProviderDemoServiceImpl implements ProviderDemoService {
    @Override
    public String sayHello() {
        return "Hello World!";
    }
}

3. 再写一个controller

import com.cloud.provider.service.ProviderDemoService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class ProviderDemo {


    @Autowired
    private ProviderDemoService providerDemoService;
    @GetMapping("/hello")
    public String hello(){
        return providerDemoService.sayHello();
    }
}

4. 配置文件

server:
  port: 9001 # 服务提供方

# 指定当前eureka客户端的注册地址,
eureka:
  client:
    service-url:
      defaultZone: http://${eureka.instance.hostname}:9000/eureka
  instance:
    hostname: localhost

#当前服务名称
spring:
  application:
    name: provider

4. 启动类

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

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

5. 启动
   

服务的调用方式（RestTemple+Feign）

RestTemplate + Ribbon子模块

1. pom

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>ribbon</artifactId>
    <version>1.0-SNAPSHOT</version>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.7.RELEASE</version>
    </parent>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <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-ribbon</artifactId>
        </dependency>
    </dependencies>
    <!--指定下载源和使用springcloud的版本-->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.SR5</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

2. 写一个调用提供服务的客户端的controller

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.loadbalancer.LoadBalancerClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class RibbonDemoController {
    @Autowired
    private LoadBalancerClient loadBalancerClient;
    @Autowired
    private RestTemplate restTemplate;

    @RequestMapping("/ribbon")
    public String helloWorld( ){

        //第一种调用方式
        //String forObject = new RestTemplate().getForObject("http://localhost:9001/hello", String.class);

        //第二种调用方式
        //根据服务名 获取服务列表 根据算法选取某个服务 并访问某个服务的网络位置。
        ServiceInstance serviceInstance = loadBalancerClient.choose("provider");
        String forObject = new RestTemplate().getForObject("http://"+serviceInstance.getHost()+":"+serviceInstance.getPort()+"/hello",String.class);

        //第三种调用方式 需要restTemplate注入的方式,需再写一个类注入Bean
        //String forObject = restTemplate.getForObject("http://provider/hello", String.class);
        return forObject;
    }

}

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class Beans {
    //管理简单对象
    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate(){
        return new RestTemplate();
    }
}

3. 配置文件

server:
  port: 9002 # 服务消费方

# 指定当前eureka客户端的注册地址,
eureka:
  client:
    service-url:
      defaultZone: http://${eureka.instance.hostname}:9000/eureka
  instance:
    hostname: localhost

#当前服务名称
spring:
  application:
    name: ribbon

4. 启动类

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

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

5. 启动
   
   ![在这里插入图片描述](https://img-blog.csdnimg.cn/22cfab7258ed4555bec5a7eedbade873.png

• 通过消费端调用服务端
  

Feign子模块

1. 提供服务（provider）的客户端需要引入openfeign依赖

<dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-openfeign</artifactId>
    </dependency>

2. 将接口暴露出来

import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;

@FeignClient(
        name = "provider",
        fallback = ProviderFallBackClient.class
)
public interface ProviderClient {

    @GetMapping("/hello")
    public String hello();
}

3. 接口调用失败的回调

import feign.hystrix.FallbackFactory;
import org.springframework.stereotype.Component;

@Component
public class ProviderFallBackClient implements FallbackFactory<ProviderClient> {

    @Override
    public ProviderClient create(Throwable throwable) {
        return new ProviderClient() {
            @Override
            public String hello() {
                return "error";
            }
        };
    }
}

5. 需额外引入提供服务的客户端（clean、install、deploy）

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>feign</artifactId>
    <version>1.0-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.7.RELEASE</version>
    </parent>
    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.example</groupId>
            <artifactId>provider</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>
    <!--指定下载源和使用springcloud的版本-->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Edgware.SR5</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

6. 配置文件

server:
  port: 9003 # 消费方

# 指定当前eureka客户端的注册地址,
eureka:
  client:
    service-url:
      defaultZone: http://${eureka.instance.hostname}:9000/eureka
  instance:
    hostname: localhost

#当前服务名称
spring:
  application:
    name: feign
   

7. 写一个调用服务方的controller，引入暴露的接口

import com.cloud.provider.client.ProviderClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class FeignDemoController {


    @Autowired
    private ProviderClient providerClient;

    @GetMapping("/feign")
    public String feign(){
        return providerClient.hello();
    }
}

8. 启动类

@SpringBootApplication
@EnableFeignClients(basePackages = "com.cloud.provider")
public class FeignApplication {
    public static void main(String[] args) {
        SpringApplication.run(FeignApplication.class,args);
    }
}

9. 启动
   
   
   ps：只要我写的hello world!越多，我会的也就越多。。。
   附上工程结构：