上一篇文章,讲述了如何通过RestTemplate+Ribbon去消费服务,这篇文章主要讲述如何通过Feign去消费服务。
Feign 采用的是基于接口的注解
准备工作
继续用上一节的工程, 启动eureka-server(服务注册中心),端口为8080; 启动service-client两次,端口分别为8081、8082.
创建一个feign的服务
新建一个spring-boot工程,取名为serice-feign,在它的pom文件引入Feign的起步依赖spring-cloud-starter-feign、Eureka的起步依赖spring-cloud-starter-eureka、Web的起步依赖spring-boot-starter-web,代码如下:
<?xml version="1.0" encoding="UTF-8"?>
<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.wzy</groupId>
<artifactId>serice-feign</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>serice-feign</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.0.5.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>
<spring-cloud.version>Finchley.SR1</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
<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.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</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>${spring-cloud.version}</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>
</project>
在工程的配置文件application.yml文件,指定程序名为service-feign,端口号为8084,服务注册地址为http://localhost:8080/eureka/ ,代码如下:
spring.application.name=service-feign
server.port=8084
eureka.client.serviceUrl.defaultZone=http://localhost:8080/eureka/
在程序的启动类ServiceFeignApplication ,加上@EnableFeignClients注解开启Feign的功能:
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class SericeFeignApplication {
public static void main(String[] args) {
SpringApplication.run(SericeFeignApplication.class, args);
}
}
定义一个feign接口,通过@ FeignClient(“服务名”),来指定调用哪个服务@RequestMapping指定服务的哪个接口。比如在代码中调用了service-client服务的“/login”接口,代码如下:
@FeignClient(value = "EUREKA-CLIENT")
public interface SchedualServiceHi {
@RequestMapping(value = "/login",method = RequestMethod.GET)
String sayHiFromClientOne(@RequestParam(value = "name") String name);
}
在Web层的controller层,对外暴露一个”/login”的API接口,通过上面定义的Feign客户端SchedualServiceHi 来消费服务。代码如下:
@RestController
public class HiController {
@Autowired
SchedualServiceHi schedualServiceHi;
@RequestMapping(value = "/login",method = RequestMethod.GET)
public String sayHi(@RequestParam String name){
return schedualServiceHi.sayHiFromClientOne(name);
}
}
启动程序,多次访问http://localhost:8084/login?name=forezp,浏览器交替显示:
what do you do 8081
what do you do 8082
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