1、什麼是Feign

Feign是一個宣告式的偽Http客戶端，它使得寫Http客戶端變得更簡單。

使用Feign，只需要建立一個介面並註解。

它具有可插拔的註解特性，可使用Feign 註解和JAX-RS註解。

Feign支援可插拔的編碼器和解碼器。

Feign預設集成了Ribbon，並和Eureka結合，

預設實現了負載均衡的效果。

簡而言之：

• Feign 採用的是基於介面的註解
• Feign 整合了ribbon

2、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.cloud</groupId>
	<artifactId>consumer-fegin</artifactId>
	<version>1.0.0</version>
	<packaging>jar</packaging>

	<name>consumer-fegin</name>
	<url>http://maven.apache.org</url>

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.2.RELEASE</version>
		<relativePath /> <!-- lookup parent from repository -->
	</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-ribbon</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<!-- 消費端 -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-feign</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>
 

application.yml

eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8888/eureka/
server:
  port: 8765
spring:
  application:
    name: consumer-feign

MemberFegin.java

package com.cloud.fegin;

import java.util.List;

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

@FeignClient(value = "service-member")
public interface MemberFegin {

	@GetMapping("/getMemberAll")
	public List<String> getList();
	
}
 

OrderFeginController.java

package com.cloud.fegin.controller;

import java.util.List;

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

import com.cloud.fegin.MemberFegin;

@RestController
public class OrderFeginController {
	

	@Autowired
	private MemberFegin memberFegin;
	
	@GetMapping("/list")
	public List<String> list(){
		System.out.println("order fgin 工程呼叫member工程");
		List<String> list = memberFegin.getList();
		return list;
	}
}
 

FeginApp.java

package com.cloud.fegin;

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;

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

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