Feign簡介
Feign 是一個聲明web服務客戶端，這便得編寫web服務客戶端更容易，使用Feign 創建一個接口并對它進行注解，它具有可插拔的注解支持包括Feign注解與JAX-RS注解，Feign還支持可插拔的編碼器與解碼器，Spring Cloud 增加了對 Spring MVC的注解，Spring Web 默認使用了HttpMessageConverters, Spring Cloud 集成 Ribbon 和 Eureka 提供的負載均衡的HTTP客戶端 Feign.
聲明式REST客戶端：Feign
先要啟動eureka_register_service工程（注冊中心）和biz-service-0工程（服務生產者）
創建一個maven工程eureka_feign_client
pom.xml
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<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> |
在應用主類中通過@EnableFeignClients注解開啟Feign功能
啟動文件FeignApplication.java
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@SpringBootApplication@EnableDiscoveryClient@EnableFeignClientspublic class FeignApplication { public static void main(String[] args) { SpringApplication.run(FeignApplication.class, args); }} |
定義服務接口類UserClient.java
使用@FeignClient("biz-service-0")注解來綁定該接口對應biz-service-0服務
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@FeignClient("biz-service-0")public interface UserClient { @RequestMapping(method = RequestMethod.GET, value = "/getuser") public User getuserinfo(); @RequestMapping(method = RequestMethod.GET, value = "/getuser") public String getuserinfostr(); @RequestMapping(method = RequestMethod.GET, value = "/info") public String info();} |
在web層中調用上面定義的UserController，具體如下
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@RestControllerpublic 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配置變量
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spring.application.name=feign-consumerserver.port=8004eureka.client.serviceUrl.defaultZone=http://localhost:8000/eureka/ |
訪問 http://127.0.0.1:8004/getuserinfo
總結：
其實通過Feign封裝了HTTP調用服務方法，使得客戶端像調用本地方法那樣直接調用方法，類似Dubbo中暴露遠程服務的方式，區別在于Dubbo是基于私有二進制協議，而Feign本質上還是個HTTP客戶端
以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持服務器之家。
原文鏈接：http://www.cnblogs.com/xiaojunbo/p/7094377.html
