spring boot2X整合nacos一使用Feign实现服务调用
服务调用有两种方式:
A.使用RestTemplate 进行服务调用 查看
B.使用Feign 进行声明式服务调用
上一次写了使用RestTemplate的方式,这次使用Feign的方式实现
服务注册发现中心使用nacos
启动nacos
spring boot 版本 2.2.1.RELEASE
1.服务端
provider
(1)添加依赖
<properties>
<java.version>1.8</java.version>
<nacos.version>2.1..RELEASE</nacos.version>
<spring-cloud.version>Greenwich.SR3</spring-cloud.version>
</properties> <dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency> <dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
<version>${nacos.version}</version>
</dependency> </dependencies> <dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
(2)修改配置
server.port= spring.application.name=service-provider spring.cloud.nacos.discovery.enabled=true
spring.cloud.nacos.discovery.server-addr=127.0.0.1:
spring.cloud.nacos.discovery.service=${spring.application.name} management.endpoints.web.exposure.include=*
management.endpoint.health.show-details=always
(3)测试方法
package com.xyz.provider.controller; import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController; @RestController
public class demoController {
@RequestMapping("/hello")
public String Hello(){
return "hello,provider";
} }
provider1
修改端口为8011
修改测试方法
package com.xyz.provider1.controller; import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController; @RestController
public class demoController {
@RequestMapping("/hello")
public String Hello(){
return "hello,another provider";
} }
启动provider和provider1
2.客户端
customer
(1)添加依赖
<properties>
<java.version>1.8</java.version>
<nacos.version>2.1..RELEASE</nacos.version>
<spring-cloud.version>Greenwich.SR4</spring-cloud.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>com.alibaba.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
<version>${nacos.version}</version>
</dependency>
<dependency>
<groupId>io.github.openfeign</groupId>
<artifactId>feign-okhttp</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
</dependencies> <dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-dependencies</artifactId>
<version>${spring-cloud.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
(2)配置
server.port=
spring.application.name=service-comsumer
management.endpoints.web.exposure.include=*
management.endpoint.health.show-details=always
spring.cloud.nacos.discovery.enabled=true
spring.cloud.nacos.discovery.server-addr=127.0.0.1:
spring.cloud.nacos.discovery.service=${spring.application.name}
(3)修改启动类
添加注解 @EnableFeignClients,开启扫描Spring Cloud Feign客户端的功能
package com.xyz.comsumer; import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@EnableFeignClients
@SpringBootApplication
public class ComsumerApplication { public static void main(String[] args) {
SpringApplication.run(ComsumerApplication.class, args);
} }
(4)添加Feign接口
创建RemoteHelloService接口,来定义OpenFeign要调用的远程服务接口
通过@FeginClient注解指定被调用方的服务名
通过fallback属性指定RemoteHelloServiceFallbackFactory类,来进行远程调用的熔断和降级处理。
provider是要调用的服务名
说明:
添加跟调用目标方法一样的方法声明,必须跟目标方法的定义一致
RemoteHelloService
package com.xyz.comsumer.feign; import com.xyz.comsumer.feign.factory.RemoteHelloServiceFallbackFactory;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping; @FeignClient(contextId = "remotehelloService", value = "service-provider", fallbackFactory = RemoteHelloServiceFallbackFactory.class)
public interface RemoteHelloService { @GetMapping("/hello")
String hello(); }
RemoteHelloServiceFallbackImpl
package com.xyz.comsumer.feign.fallback; import com.xyz.comsumer.feign.RemoteHelloService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component; @Component
public class RemoteHelloServiceFallbackImpl implements RemoteHelloService {
private final Logger logger = LoggerFactory.getLogger(RemoteHelloServiceFallbackImpl.class);
private Throwable cause; @Override
public String hello() {
logger.error("feign 查询信息失败:{}", cause);
return null;
} public Throwable getCause() {
return cause;
} public void setCause(Throwable cause) {
this.cause = cause;
} }
RemoteHelloServiceFallbackFactory
package com.xyz.comsumer.feign.factory; import com.xyz.comsumer.feign.RemoteHelloService;
import com.xyz.comsumer.feign.fallback.RemoteHelloServiceFallbackImpl;
import feign.hystrix.FallbackFactory;
import org.springframework.stereotype.Component; @Component
public class RemoteHelloServiceFallbackFactory implements FallbackFactory<RemoteHelloService> { @Override
public RemoteHelloService create(Throwable throwable) {
RemoteHelloServiceFallbackImpl remoteFallback = new RemoteHelloServiceFallbackImpl();
remoteFallback.setCause(throwable);
return remoteFallback;
}
}
要使用Feign的fallback机制,需要开启Feign的Hystrix的功能
增加配置
feign.hystrix.enabled=true
(4)服务调用
注入刚才声明的ProviderService,就可以像本地方法一样进行调用了
package com.xyz.comsumer.controller; import com.xyz.comsumer.feign.RemoteHelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController; @RestController
public class FeignController {
@Autowired
RemoteHelloService remoteHelloService;
@RequestMapping("feignTest")
public String feignTest(){
return remoteHelloService.hello();
}
}
启动customer
访问http://localhost:8015/call
交替返回结果
hello,provider 或 hello,another provider
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