Feign 是一个声明web服务客户端，这便得编写web服务客户端更容易，使用Feign 创建一个接口并对它进行注解，它具有可插拔的注解支持包括Feign注解与JAX-RS注解，Feign还支持可插拔的编码器与解码器，Spring Cloud 增加了对 Spring MVC的注解，Spring Web 默认使用了HttpMessageConverters, Spring Cloud 集成 Ribbon 和 Eureka 提供的负载均衡的HTTP客户端 Feign.
先要启动eureka_register_service工程（注册中心）和biz-service-0工程（服务提供方）
创建一个maven工程eureka_feign_client
pom.xml
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>
1.4
.
3
.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-
8
</project.build.sourceEncoding>
<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-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>Brixton.SR5</version>
<type>pom</type>
<scope>
import
</scope>
</dependency>
</dependencies>
</dependencyManagement>
在应用主类中通过@EnableFeignClients注解开启Feign功能
启动文件FeignApplication.java
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public
class
FeignApplication {
public
static
void
main(String[] args) {
SpringApplication.run(FeignApplication.
class
, args);
}
}
定义服务接口类UserClient.java
使用@FeignClient("biz-service-0")注解来绑定该接口对应biz-service-0服务
@FeignClient
(
"biz-service-0"
)
public
interface
UserClient {
@RequestMapping
(method = RequestMethod.GET, value =
"/访问路径名称/{id}"
)
public
User getuserinfo(@PathVariale("id") Long id);//参数不为基本类型，是对象的时候只能使用post方法;
@RequestMapping
(method = RequestMethod.GET, value =
"/getuser"
)
public
String getuserinfostr();
@RequestMapping
(method = RequestMethod.GET, value =
"/info"
)
public
String info();
}
在web层中调用上面定义的UserController，具体如下
@RestController
public
class
UserController {
@Autowired
UserClient userClient;
@RequestMapping
(value =
"/getuserinfo"
, method = RequestMethod.GET)
public
User getuserinfo() {
return
userClient.getuserinfo();
}
@RequestMapping
(value =
"/getuserinfostr"
, method = RequestMethod.GET)
public
String getuserinfostr() {
return
userClient.getuserinfostr();
}
@RequestMapping
(value =
"/info"
, method = RequestMethod.GET)
public
String info() {
return
userClient.info();
}
}
application.properties配置变量
spring.application.name=feign-consumer
server.port=
8004
eureka.client.serviceUrl.defaultZone=http:
//localhost:8000/eureka/
总结：
其实通过Feign封装了HTTP调用服务方法，使得客户端像调用本地方法那样直接调用方法，类似Dubbo中暴露远程服务的方式，区别在于Dubbo是基于私有二进制协议，而Feign本质上还是个HTTP客户端
转载自：http://www.cnblogs.com/xiaojunbo/p/7094377.html