spring boot2X整合Consul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Consul

启动Consul

consul agent -dev

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>
    <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>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-consul-discovery</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）修改配置

server.port=8010

spring.application.name=provider
spring.cloud.consul.host=localhost
spring.cloud.consul.port=8500
spring.cloud.consul.discovery.health-check-path=/actuator/health
spring.cloud.consul.discovery.service-name=service-provider
spring.cloud.consul.discovery.heartbeat.enabled=true

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>
     <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>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-consul-discovery</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=8015
spring.application.name=xyz-comsumer
spring.cloud.consul.host=localhost
spring.cloud.consul.port=8500
spring.cloud.consul.discovery.register=false
spring.cloud.consul.discovery.health-check-url=/actuator/health
spring.cloud.consul.discovery.heartbeat.enabled=true
management.endpoints.web.exposure.include=*
management.endpoint.health.show-details=always

（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

添加注解@FeignClient(name = "provider")

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

package com.xyz.consumer.controller;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;

@FeignClient(name = "provider")
public interface ProviderService {

    @RequestMapping("/hello")
    public String hello();
    
}

（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.consumer.controller;

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
    private ProviderService providerService;
    
    @RequestMapping("/call")
    public String call() {
        return providerService.hello();
    }
}

启动customer

访问http://localhost:8015/call

交替返回结果

　　hello,provider 或 hello,another provider