Spring Cloud Feign
Spring Cloud Feign 是一套基于Netflix Feign实现的声明式服务调用客户端。它使得编写Web服务客户端变得更加简单,我们只需要创建接口并使用注解来配置它既可完成对web服务接口的绑定。它具备可插拔的注解支持,包括Feign注解、JAX-RS注解。它也支持可插拔的编码器和解码器。Spring Cloud Feign还扩展了对Spring MVC注解的支持,同时还整合了Ribbon和Eureka来提供负载均衡的Http客户端实现。
新建com.david.feign项目,并在pom.xml中增加依赖:
<?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.david</groupId> <artifactId>feign</artifactId> <version>0.0.1-SNAPSHOT</version> <packaging>jar</packaging> <name>feign</name> <description>Demo project for Spring Boot</description> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.9.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.boot</groupId> <artifactId>spring-boot-starter</artifactId> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-feign</artifactId> </dependency> </dependencies> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Edgware.SR2</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>
编辑配置文件application.yml:
spring:
application:
name: david-feign
server:
port: 8765
eureka:
client:
service-url:
defaultZone: http://localhost:8761/eureka/
在启动类程序中,加上@EnableFeignClients注解开启Feign功能:
@EnableDiscoveryClient @EnableFeignClients @SpringBootApplication public class FeignApplication { public static void main(String[] args) { SpringApplication.run(FeignApplication.class, args); } }
创建一个Feign的客户端接口定义。使用@FeignClient注解来制定这个接口所要调用的服务名称,接口中定义的各个函数使用Spring MVC的注解就可以来绑定服务提供的REST接口,比如下面就是绑定david-eureka服务的/test接口。
@FeignClient("david-eureka-client") public interface TestFeignService { @GetMapping("/test") String consumer(); }
新建testController.java 注入feign 完成调用。
@RestController public class TestController { @Autowired TestFeignService testFeignService; @GetMapping("/test") public String test(){ return testFeignService.consumer(); } }
启动项目,访问http://localhost:8765/test
项目目录: