SpringCloud之Feign(客户端负载均衡)

1、Feign是一个声明式的web服务客户端，使得编写web服务客户端变得非常容易；只需要创建一个接口，然后在上面添加注解即可；

2、引入Ribbon依赖：

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1<dependencies>

2       <dependency><!-- 自己定义的api -->

3           <groupId>com.atguigu.springcloud</groupId>

4           <artifactId>microservicecloud-api</artifactId>

5           <version>${project.version}</version>

6       </dependency>

7       <dependency>

8           <groupId>org.springframework.cloud</groupId>

9           <artifactId>spring-cloud-starter-feign</artifactId>

10      </dependency>

11      <!-- Ribbon相关 -->

12      <dependency>

13          <groupId>org.springframework.cloud</groupId>

14          <artifactId>spring-cloud-starter-eureka</artifactId>

15      </dependency>

16      <dependency>

17          <groupId>org.springframework.cloud</groupId>

18          <artifactId>spring-cloud-starter-ribbon</artifactId>

19      </dependency>

20      <dependency>

21          <groupId>org.springframework.cloud</groupId>

22          <artifactId>spring-cloud-starter-config</artifactId>

23      </dependency>

24      <dependency>

25          <groupId>org.springframework.boot</groupId>

26          <artifactId>spring-boot-starter-web</artifactId>

27      </dependency>

28      <!-- 修改后立即生效，热部署 -->

29      <dependency>

30          <groupId>org.springframework</groupId>

31          <artifactId>springloaded</artifactId>

32      </dependency>

33      <dependency>

34          <groupId>org.springframework.boot</groupId>

35          <artifactId>spring-boot-devtools</artifactId>

36      </dependency>

37  </dependencies>

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2、配置application.yml文件：

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1server:

2  port: 80

3feign: 

4  hystrix: 

5    enabled: true

6eureka:

7  client:

8    register-with-eureka: false

9    service-url: 

10      defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/,http://eureka7003.com:7003/eureka/  

11

3、启动类开启注解(@EnableFeignClients)

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1import org.springframework.boot.SpringApplication;

2import org.springframework.boot.autoconfigure.SpringBootApplication;

3import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

4import org.springframework.cloud.netflix.feign.EnableFeignClients;

5import org.springframework.context.annotation.ComponentScan;

6

7@SpringBootApplication

8@EnableEurekaClient

9@EnableFeignClients(basePackages= {"com.atguigu.springcloud"})

10@ComponentScan("com.atguigu.springcloud")

11public class DeptConsumer80_Feign_App

12{

13  public static void main(String[] args)

14  {

15      SpringApplication.run(DeptConsumer80_Feign_App.class, args);

16  }

17}

18

19

4、编写配置类，注入：RestTemplate

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1import org.springframework.cloud.client.loadbalancer.LoadBalanced;

2import org.springframework.context.annotation.Bean;

3import org.springframework.context.annotation.Configuration;

4import org.springframework.web.client.RestTemplate;

5import com.netflix.loadbalancer.IRule;

6import com.netflix.loadbalancer.RetryRule;

7

8@Configuration

9public class ConfigBean //boot -->spring   applicationContext.xml --- @Configuration配置   ConfigBean = applicationContext.xml

10{ 

11  @Bean

12  @LoadBalanced//Spring Cloud Ribbon是基于Netflix Ribbon实现的一套客户端       负载均衡的工具。

13  public RestTemplate getRestTemplate()

14  {

15      return new RestTemplate();

16  }

17  

18}

19

5、定义DeptClientService接口：

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1@FeignClient(value = "MICROSERVICECLOUD-DEPT",fallbackFactory=DeptClientServiceFallbackFactory.class)

2public interface DeptClientService

3{

4   @RequestMapping(value = "/dept/get/{id}", method = RequestMethod.GET)

5   public Dept get(@PathVariable("id") long id);

6

7   @RequestMapping(value = "/dept/list", method = RequestMethod.GET)

8   public List<Dept> list();

9

10  @RequestMapping(value = "/dept/add", method = RequestMethod.POST)

11  public boolean add(Dept dept);

12}

13

14

6、编写DeptController_Consumer：

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1import java.util.List;

2import org.springframework.beans.factory.annotation.Autowired;

3import org.springframework.web.bind.annotation.PathVariable;

4import org.springframework.web.bind.annotation.RequestMapping;

5import org.springframework.web.bind.annotation.RestController;

6import com.atguigu.springcloud.entities.Dept;

7import com.atguigu.springcloud.service.DeptClientService;

8

9@RestController

10public class DeptController_Consumer

11{

12  @Autowired

13  private DeptClientService service;

14

15  @RequestMapping(value = "/consumer/dept/get/{id}")

16  public Dept get(@PathVariable("id") Long id)

17  {

18      return this.service.get(id);

19  }

20

21  @RequestMapping(value = "/consumer/dept/list")

22  public List<Dept> list()

23  {

24      return this.service.list();

25  }

26

27  @RequestMapping(value = "/consumer/dept/add")

28  public Object add(Dept dept)

29  {

30      return this.service.add(dept);

31  }

32}

33