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這篇文章主要介紹“SpringCloud OpenFeign如何實(shí)現(xiàn)”的相關(guān)知識(shí),小編通過實(shí)際案例向大家展示操作過程,操作方法簡單快捷,實(shí)用性強(qiáng),希望這篇“SpringCloud OpenFeign如何實(shí)現(xiàn)”文章能幫助大家解決問題。
OpenFeign是使用接口+注解實(shí)現(xiàn)的,因此了解它的常用注解是必要的,有以下幾個(gè):
@EnableFeignClients:在啟動(dòng)類上添加,用于開啟OpenFeign功能。當(dāng)項(xiàng)目啟動(dòng)時(shí),會(huì)掃描帶有@FeignClient的接口,生成代理類并注冊(cè)到Spring容器中
@FeignClient:通知OpenFeign組件對(duì)該注解下的接口進(jìn)行解析,通過動(dòng)態(tài)代理的方式產(chǎn)生實(shí)現(xiàn)類,完成服務(wù)調(diào)用
@RequestMapping:SpringMvc中的注解,不過此時(shí)該注解表示發(fā)起Request請(qǐng)求(默認(rèn)Get方式)
@GetMapping:SpringMvc中的注解,不過此時(shí)該注解表示發(fā)起Get請(qǐng)求
@PostMapping:SpringMvc中的注解,不過此時(shí)該注解表示發(fā)起Post請(qǐng)求
首先得把Nacos啟動(dòng)
服務(wù)提供方,
bootstrap.yml:
server:
port: 8083
servlet:
context-path: /nacosProviderspring:
application:
name: nacos-provider
cloud:
nacos:
discovery:
server-addr: 127.0.0.1:8848
引入依賴:
<dependencies> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery </artifactId> <version>2.2.0.RELEASE</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency> </dependencies>
服務(wù)方法:
@Controller @RequestMapping("/provide") public class ProviderController { @RequestMapping("/distribute") @ResponseBody public String distribute() { return "吃雞胸肉"; } @RequestMapping("/distribute1") @ResponseBody public String distribute1(String name, Integer age) { return "姓名:" + name + ",年齡:" + age; } @PostMapping("/distribute2") @ResponseBody public String distribute2(@RequestBody Person p) { return "身高:" + p.getHeight() + ",膚色:" + p.getSkin(); } }
import lombok.Data; @Data public class Person { private Integer height; private String skin; }
服務(wù)調(diào)用方,
bootstrap.yml
server:
port: 8082
servlet:
context-path: /nacosInvokespring:
application:
name: nacos-invoke
cloud:
nacos:
discovery:
server-addr: 127.0.0.1:8848
引入依賴:
<dependencies> <dependency> <groupId>com.alibaba.cloud</groupId> <artifactId>spring-cloud-starter-alibaba-nacos-discovery </artifactId> <version>2.2.0.RELEASE</version> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-openfeign</artifactId> <version>2.2.0.RELEASE</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> </dependency> </dependencies>
啟動(dòng)類上添加注解:
import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.openfeign.EnableFeignClients; //開啟OpenFeign @EnableFeignClients @SpringBootApplication public class NacosInvokeApplication { public static void main(String[] args) { SpringApplication.run(NacosConfigApplication.class, args); } }
創(chuàng)建@FeignClient修飾的接口:
import com.gs.nacos_invoke.dto.Person; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestParam; /** * value值是服務(wù)提供方的服務(wù)名稱 */ @FeignClient(value = "nacos-provider") public interface InvokeClient { @GetMapping("/nacosProvider/provide/distribute") String distribute(); @GetMapping("/nacosProvider/provide/distribute1") String distribute1(@RequestParam("name") String name, @RequestParam("age") Integer age); @PostMapping("/nacosProvider/provide/distribute2") String distribute2(@RequestBody Person p); }
Person類(服務(wù)調(diào)用方再創(chuàng)建一個(gè),不是同一個(gè)):
import lombok.Data; @Data public class Person { private Integer height; private String skin; }
編寫控制器,使用接口請(qǐng)求提供方的服務(wù):
import com.gs.nacos_invoke.dto.Person; import com.gs.nacos_config.feign.InvokeClient; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RequestMapping; @Controller @RequestMapping("/user") public class UserController { @Autowired private InvokeClient invokeClient; @GetMapping("/invoke") public void invoke(String name, Integer age) { String str = invokeClient.distribute(); System.out.println(str); } @GetMapping("/invoke1") public void invoke1() { String str = invokeClient.distribute1("coder", 20); System.out.println(str); } @GetMapping("/invoke2") public void invoke2() { Person p = new Person(); p.setHeight(183); p.setSkin("黃皮膚"); String s = invokeClient.distribute2(p); System.out.println(s); } }
OpenFeign是基于Ribbon的,所以它默認(rèn)是負(fù)載均衡的。其次,它也是基于Hystrix的,有超時(shí)降級(jí)的處理:默認(rèn)服務(wù)提供方的接口超時(shí)時(shí)間是1s,超過1s服務(wù)調(diào)用方會(huì)報(bào)錯(cuò)。1s是可以配置的,按照業(yè)務(wù)需要調(diào)整。@FeignClient注解有個(gè)fallback屬性,當(dāng)該屬性有值時(shí),服務(wù)提供方超時(shí),會(huì)返回程序所指定的降級(jí)值。
服務(wù)調(diào)用方,bootstrap.yml添加(更規(guī)范的做法是引入spring-cloud-starter-alibaba-nacos-config依賴,nacos中新建配置,然后在這個(gè)配置中添加):
feign:
hystrix:
enabled: true
ribbon:
# 請(qǐng)求連接的超時(shí)時(shí)間
ConnectionTimeout: 3000
# 請(qǐng)求處理的超時(shí)時(shí)間
ReadTimeout: 3000hystrix:
command:
default:
execution:
isolation:
thread:
timeoutInMilliseconds: 3000
接口修改為:
import com.gs.nacos_invoke.dto.Person; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.PostMapping; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestParam; @FeignClient(value = "nacos-provider", fallback = InvokeClientFallback.class) public interface InvokeClient { @GetMapping("/nacosProvider/provide/distribute") String distribute(); @GetMapping("/nacosProvider/provide/distribute1") String distribute1(@RequestParam("name") String name, @RequestParam("age") Integer age); @PostMapping("/nacosProvider/provide/distribute2") String distribute2(@RequestBody Person p); }
fallback指定的類:
import com.gs.nacos_invoke.dto.Person; import org.springframework.stereotype.Component; @Component public class InvokeClientFallback implements InvokeClient { @Override public String distribute() { return "超時(shí)3s"; } @Override public String distribute1(String name, Integer age) { return "超時(shí)3s"; } @Override public String distribute2(Person p) { return "超時(shí)3s"; } }
服務(wù)提供方ProviderController類的方法中,加入Thread.sleep(4000);或者throw new RuntimeException("拋異常");來觸發(fā)降級(jí)(拋出未捕獲的異常也能觸發(fā))。
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