Feign服务消费者

Feign的优点：面向接口，完全不用管实现，传入规定格式的数据就可以了

搭建消费者项目（FeignDemo）

1、创建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>
    <groupId>com.cppdy</groupId>
    <artifactId>FeignDemo</artifactId>
    <version>0.0.1-SNAPSHOT</version>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath />
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Dalston.RC1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

    <repositories>
        <repository>
            <id>spring-milestones</id>
            <name>Spring Milestones</name>
            <url>https://repo.spring.io/milestone</url>
            <snapshots>
                <enabled>false</enabled>
            </snapshots>
        </repository>
    </repositories>

</project>

2、创建application.yml配置文件

eureka:
  client:
    service-url:
      defaultZone: http://127.0.0.1:9000/eureka/
server:
  port: 9004
spring:
  application:
    name: cppdy-feign

3、创建HelloService接口

package com.cppdy.service;

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

@FeignClient(value = "cppdy-hello")
public interface HelloService {

    @RequestMapping("hello")
    String hello(@RequestParam("name") String name);
}

4、创建HelloController类

package com.cppdy.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.cppdy.service.HelloService;

@RestController
public class HelloController {

    @Autowired
    private HelloService helloService;

    @RequestMapping("hello")
    public String hello(String name) {

        return helloService.hello(name);
    }

}

5、创建启动类（FeignApp）

package com.cppdy;

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

@SpringBootApplication
//开启服务发现
@EnableDiscoveryClient
//开启feign
@EnableFeignClients
public class FeignApp {

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

}

6、先启动EurekaDemo（注册中心项目），再启动2个ProduceDemo（服务提供者项目）端口号分别设置为9001、9002，再启动FeignDemo（消费者项目）端口号设置为9004，一直访问http://localhost:9004/hello，会自动轮流调用9001和9002的hello方法（负载均衡）