简介
feign是声明式的web service客户端，它让微服务之间的调用变得更简单了，类似controller调用service。Spring Cloud集成了Ribbon和Eureka，可在使用Feign时提供负载均衡的http客户端。
在springcloud中不仅可以使用Ribbo进行负载均衡，也可以使用Feign。Feign是在Ribbon的基础上进行了一次改进，采用接口的方式实现负载均衡。
使用
导入依赖
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< dependency > < groupId >org.springframework.cloud</ groupId > < artifactId >spring-cloud-starter-openfeign</ artifactId > </ dependency > |
编写对应的接口
@FeignClient(value = "PROVIDER-NAME")声明这是一个FeignClient，value指明需要的服务id
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@FeignClient (value = "PROVIDER-NAME" ) public interface DeptClientService { // 请求的路径需与服务提供者的路径一致 @RequestMapping (value = "/dev/add" ) boolean add(Dept dept);
@RequestMapping (value = "/dev/{id}" ) Dept queryByID( @PathVariable ( "id" ) Long id );
@PostMapping (value = "/dev/list" ) List<Dept> queryAll(); } |
修改Controller
我们不再使用RestTemplate来获取所需的对象，而是通过之前定义的接口来获取
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@RestController public class ConsumerController { @Autowired private DeptClientService service; @RequestMapping ( "/consumer/get/{id}" ) public Dept getByID( @PathVariable ( "id" ) Long id){ return this .service.queryByID(id); } @RequestMapping ( "/consumer/add" ) public boolean add(String dname){ Dept dept = new Dept(); dept.setDname(dname); return this .service.add(dept); } @RequestMapping ( "/consumer/list" ) public List<Dept> list(){ return this .service.queryAll(); }
} |
修改启动类
@EnableFeignClients 开启Feign负载均衡
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@SpringBootApplication (scanBasePackages = "com" ) @EnableEurekaClient @EnableFeignClients (basePackages = "com.service" ) public class FeignApplication { public static void main(String[] args) { SpringApplication.run(FeignApplication. class ,args); } } |
对比:
Ribbon
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public class ConsumerController { @Autowired private RestTemplate template; private static final String url= "http://PROVIDER-NAME" ; @RequestMapping ( "/consumer/get/{id}" ) public Dept getByID( @PathVariable long id){ //请求的路径，返回的对象 Dept getEntity = template.getForObject(url + "/dev/" + id, Dept. class ); return getEntity; } @RequestMapping ( "/consumer/add" ) public boolean add(String dname){ Dept dept = new Dept(); dept.setDname(dname); System.out.println(dept); //请求的路径，传递的参数，返回的对象 return template.postForObject(url+ "/dev/add" ,dept,Boolean. class ); } @RequestMapping ( "/consumer/list" ) public List<Dept> list(){ //请求的路径，返回的对象 return template.postForObject(url+ "/dev/list" , void . class ,List. class ); }
} |
Feign
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@RestController public class ConsumerController { @Autowired private DeptClientService service; @RequestMapping ( "/consumer/get/{id}" ) public Dept getByID( @PathVariable ( "id" ) Long id){ return this .service.queryByID(id); } @RequestMapping ( "/consumer/add" ) public boolean add(String dname){ Dept dept = new Dept(); dept.setDname(dname); return this .service.add(dept); } @RequestMapping ( "/consumer/list" ) public List<Dept> list(){ return this .service.queryAll(); }
} |
总结
Feign的使用与Ribbon不同的地方在于
Feign通过接口来实现，更符合我们的面向接口编程的习惯 在Ribbon的Controller中我们需要将url拼接，而Feign帮我们进行了拼接以上就是SpringCloud Feign的使用简介的详细内容，更多关于SpringCloud Feign的资料请关注其它相关文章！
原文链接：https://juejin.cn/post/6950254699895324679
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