组件名：Netflix Eureka
作用：支撑微服务的自注册、自发现，提供负载均衡能力
开发环境使用IDEA，jdk1.8
一、搭建eureka服务
1.新建maven项目，配置pom.xml文件
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<parent>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-parent</artifactId>
<version>Camden.SR7</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
</dependencies>
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2.新建启动类
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@SpringBootApplication
@EnableEurekaServer
public
class
Application {
public
static
void
main(String[] args){
SpringApplication.run(Application.
class
,args);
}
}
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3.新建配置文件application.yml
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server:
port:
1000
eureka:
instance:
hostname: localhost
client:
register-with-eureka:
false
fetch-registry:
false
spring:
application:
name: eureka-server
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4.启动（启动类）
5.访问 eureka：http://localhost:1000/
erueka服务器启动成功，目前还未有服务注册
二、搭建服务提供方
1.新建maven项目，配置pom.xml文件
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<parent>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-parent</artifactId>
<version>Camden.SR7</version>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka-server</artifactId>
</dependency>
</dependencies>
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2.创建Application启动类，提供/hello服务
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@Configuration
@ComponentScan
@EnableEurekaClient
@EnableAutoConfiguration
@RestController
public
class
Application {
@RequestMapping
(value =
"hello"
,method = RequestMethod.GET)
public
String hello(){
return
"你好,世界"
;
}
public
static
void
main(String[] args){
new
SpringApplicationBuilder(Application.
class
).web(
true
)
.run(args);
}
}
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3、新建application.yml配置文件
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eureka:
client:
serviceUrl:
defaultZone: http:
//localhost:1000/eureka/
spring:
application:
name: feign-client-test-
001
server:
port:
2000
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查看路径id展示，需要添加配置
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eureka:
client:
serviceUrl:
defaultZone: http:
//admin:admin123@localhost:1000/eureka
instance:
prefer-ip-address:
true
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4、运行，查看之前Erueka服务端的页面，FEIGN-CLIENT-TEST-001在注册中心变为了大写这个注意下
5、访问：http://127.0.0.1:2000/hello
三、搭建服务消费方
使用@FeignClient注解
Feign is a declarative web service client. It makes writing web service clients easier.
如上是Spring Cloud文档中对于Feign的定义，结合之前的两篇博文，在这里我们就可以吧Feign简单的理解为用户（前端）可以直接接触到的REST接口提供者。在Feign中，我们可以方便的访问和使用意已经在Erueka服务器中注册过的服务了。
1、建立maven工程，配置pom.xml文件
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<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-feign</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-eureka</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>Camden.SR6</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>
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2、建立包及启动类FeignApplication
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/**
* Created by gaofeng on 2017/7/14.
*/
@Configuration
@ComponentScan
@EnableAutoConfiguration
@EnableEurekaClient
@EnableFeignClients
@SpringBootApplication
public
class
FeignApplication {
public
static
void
main(String[] args) {
SpringApplication.run(FeignApplication.
class
, args);
}
}
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3、建立接口类，用来调用上文中FEIGN-CLIENT-TEST-001服务的方法hello()，FEIGN-CLIENT-TEST-001是全大写的
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@FeignClient
(
"FEIGN-CLIENT-TEST-001"
)
public
interface
IHello {
@RequestMapping
(value =
"/hello"
,method = RequestMethod.GET)
String hello();
}
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其中@FeignClient中指定需要调用的微服务的名称（全大写），@RequestMapping中指定访问微服务响应接口的路径，如之前微服务的hello方法是通过"/hello"路径访问，那么这里需要配置一致
4、新建Controller类，为前端提供REST接口
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@RestController
public
class
HelloController {
@Autowired
private
IHello iHello;
@RequestMapping
(value =
"gethello"
,method = RequestMethod.GET)
public
String getHello() {
return
iHello.hello();
}
}
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5、配置Feign的配置文件，指定Eureka服务器注册地址和访问端口application.yml
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server:
port:
8081
eureka:
client:
serviceUrl:
defaultZone: http:
//localhost:1000/eureka/
spring:
application:
name: feign-client-test-
002
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6、运行，查看之前Erueka服务端的页面
7、访问：http://127.0.0.1:8081/gethello
这里访问的就是feign-client-test-001的hello服务。
本文转自gaofeng36599 51CTO博客，原文链接:http://blog.51cto.com/786678398/1947471
