Feign的使用步骤
Feign只需要创建一个接口,然后在上面添加注解即可;
新建microservicecloud-consumer-dept-feign
microservicecloud-consumer-dept-feign工程的pom.xml,主要添加对feign的支持
<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>
<parent>
<groupId>com.yt.springcloud</groupId>
<artifactId>microservicecloud</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<artifactId>microservicecloud-consumer-dept-feign</artifactId>
<dependencies>
<dependency><!-- 自己定义的api -->
<groupId>com.yt.springcloud</groupId>
<artifactId>microservicecloud-api</artifactId>
<version>${project.version}</version>
</dependency>
<dependency><!-- springboot-web -->
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- 修改后立即生效,热部署 (一修改,自动发布,自动构建)-->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>springloaded</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
<!-- Ribbon相关 (eureka后面没有server的就是客户端,ribbon要跟eureka整合,类似于mysql和java的驱动包)-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-ribbon</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-config</artifactId>
</dependency>
<!-- feign的依赖 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
</dependencies>
</project>
修改microservicecloud-api工程的pom.xml
<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>
<parent><!-- 子类里面显示声明才能有明确的继承表现,无意外就是父类的默认版本否则自己定义 -->
<groupId>com.yt.springcloud</groupId>
<artifactId>microservicecloud</artifactId>
<version>0.0.1-SNAPSHOT</version>
</parent>
<artifactId>microservicecloud-api</artifactId><!-- 当前Module我自己叫什么名字 -->
<dependencies><!-- 当前Module需要用到的jar包,按照自己的需求添加,如果父类已经包含了,可以不用写版本号 -->
<!-- 实体类的自动生成set,get,全参构造方法,toString等等 -->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
</dependency>
<!-- feign的依赖 -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-feign</artifactId>
</dependency>
</dependencies>
</project>
microservicecloud-api工程添加一个DeptClientService接口并新增注解@FeignClient
package com.yt.springcloud.service;
import java.util.List;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import com.yt.springcloud.entity.Dept;
/**
*
* @Description: 修改microservicecloud-api工程,根据已经有的DeptClientService接口
* 一个实现了FallbackFactory接口的类DeptClientServiceFallbackFactory
* @author zzyy
* @date 2018年4月21日
*/
@FeignClient(value = "MICROSERVICECLOUD-DEPT")//针对于更细粒化的控制,针对哪一个微服务进行面向接口的feign的
//@FeignClient(value = "MICROSERVICECLOUD-DEPT",fallbackFactory=DeptClientServiceFallbackFactory.class)
public interface DeptClientService
{
@RequestMapping(value = "/dept/get/{id}", method = RequestMethod.GET)
public Dept get(@PathVariable("id") long id);
@RequestMapping(value = "/dept/list", method = RequestMethod.GET)
public List<Dept> list();
@RequestMapping(value = "/dept/add", method = RequestMethod.POST)
public boolean add(Dept dept);
}
对api公共项目工程maven clean–>maven install
microservicecloud-consumer-dept-feign工程修改Controller,
添加上一步新建的DeptClientService
package com.yt.springcloud.controller;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import com.yt.springcloud.entity.Dept;
import com.yt.springcloud.service.DeptClientService;
@RestController
public class DeptController_consumer {
@Autowired
private DeptClientService service;
@RequestMapping(value = "/consumer/dept/get/{id}")
public Dept get(@PathVariable("id") Long id)
{
return this.service.get(id);
}
@RequestMapping(value = "/consumer/dept/list")
public List<Dept> list()
{
return this.service.list();
}
@RequestMapping(value = "/consumer/dept/add")
public Object add(Dept dept)
{
return this.service.add(dept);
}
}
microservicecloud-consumer-dept-feign工程修改主启动类
package com.yt.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.context.annotation.ComponentScan;
@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients(basePackages= {"com.yt.springcloud"})
@ComponentScan("com.yt.springcloud")
public class DeptConsumer80_Feign_App {
public static void main(String[] args) {
SpringApplication.run(DeptConsumer80_Feign_App.class, args);
}
}
测试
Feign集成了Ribbon
利用Ribbon维护了microservicecloud-Dept的服务列表信息,并且通过轮询实现了客户端的负载均衡,而与Ribbon不同的是,通过feign只需要定义服务绑定接口且以声明式的方法,优雅而简单的实现了服务调用