Feign is a declarative web service client, which makes it easier to write web service clients. Use Feign to create an interface and annotate it. It has pluggable annotation support including Feign annotations and JAX-RS annotations. Feign also Supports pluggable encoders and decoders, Spring Cloud adds annotations to Spring MVC, Spring Web uses HttpMessageConverters by default, Spring Cloud integrates the load balancing HTTP client Feign provided by Ribbon and Eureka.
First start the eureka_register_service project (registration center) and the biz-service-0 project (service provider)
Create a maven project 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>
Enable Feign function through @EnableFeignClients annotation in the main class of the application
Start the file FeignApplication.java
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public
class
FeignApplication {
public
static
void
main(String[] args) {
SpringApplication.run(FeignApplication.
class
, args);
}
}
Define the service interface class UserClient.java
Use the @FeignClient("biz-service-0") annotation to bind the interface corresponding to the biz-service-0 service
@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();
}
@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 configuration variable
spring.application.name=feign-consumer
server.port=
8004
eureka.client.serviceUrl.defaultZone=http:
//localhost:8000/eureka/
Summarize:
In fact, Feign encapsulates the HTTP call service method, so that the client can directly call the method like a local method, similar to the way Dubbo exposes remote services, the difference is that Dubbo is based on a private binary protocol, while Feign is essentially an HTTP client
Reprinted from: http://www.cnblogs.com/xiaojunbo/p/7094377.html