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文章目录
前言
上篇文章, Spring Cloud Alibaba学习笔记:4、创建服务消费者(RestTemplate + LoadBalancerClient),
我们一起学习了 使用 RestTemplate + LoadBalancerClient 的方式 去创建服务消费者,但是依旧显得繁琐,本文,我们将结合使用 spring-cloud-openfeign 来创建服务消费者,简化消费调用…
一起开始吧
Feign 概述
Feign 是一个声明式的伪 Http 客户端,它使得写 Http 客户端变得更简单。使用 Feign,只需要创建一个接口并注解。它具有可插拔的注解特性,可使用 Feign 注解和 JAX-RS 注解。Feign 支持可插拔的编码器和解码器。Feign 默认集成了 Ribbon,Nacos 也很好的兼容了 Feign,默认实现了负载均衡的效果
- Feign 采用的是基于接口的注解
- Feign 整合了 ribbon
创建feign 服务消费者
1、 创建一个maven module 项目 sca-nacos-discovery-consumer-feign
2、 pom
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>cn.fxbin.learn</groupId>
<artifactId>sca</artifactId>
<version>1.0</version>
</parent>
<artifactId>sca-nacos-discovery-consumer-feign</artifactId>
<version>1.0</version>
<name>sca-nacos-discovery-consumer-feign</name>
<description>Spring Cloud Alibaba Nacos Discovery Consumer Feign Service Project</description>
<dependencies>
<!-- spring-boot web -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<!-- nacos-discovery -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>
<!-- openfeign -->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
3、创建应用主类别 ScaNacosFeignApplication
package cn.fxbin.learn.sca.nacos.consumer;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class ScaNacosFeignApplication {
public static void main(String[] args) {
SpringApplication.run(ScaNacosFeignApplication.class, args);
}
}
4、创建 feign 客户端
package cn.fxbin.learn.sca.nacos.consumer.client;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
/**
* DiscoveryClient
*
* @author fxbin
* @version v1.0
* @since 2019/7/7 22:47
*/
@FeignClient("sca-nacos-discovery-provider")
public interface DiscoveryClient {
@GetMapping(value = "/echo/{message}")
String echo(@PathVariable String message);
}
5、创建 ConsumerController
package cn.fxbin.learn.sca.nacos.consumer.controller;
import cn.fxbin.learn.sca.nacos.consumer.client.DiscoveryClient;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
/**
* ConsumerController
*
* @author fxbin
* @version v1.0
* @since 2019/7/7 20:36
*/
@Slf4j
@RestController
public class ConsumerController {
@Resource
private DiscoveryClient discoveryClient;
@GetMapping(value = "/test")
public String test() {
return discoveryClient.echo(" !^@^! ");
}
}
6、配置服务端口、名称、服务端点检查和Nacos地址
server:
port: 9033
management:
endpoints:
web:
exposure:
include: "*"
spring:
application:
name: sca-nacos-discovery-consumer-feign
cloud:
nacos:
discovery:
server-addr: 127.0.0.1:8848
7、启动Feign服务消费者
8、检查nacos 控制台
9、测试消费者
> 测试服务消费API
postman 调用 api: http://localhost:9033/test
> 测试服务负载
- 修改
sca-nacos-discovery-provider
服务 api, 打印当前服务端口
@RestController
public class EchoController {
@Value("${server.port}")
private String port;
@GetMapping(value = "/echo/{message}")
public String echo(@PathVariable String message) {
return "Hello Nacos Discovery Provider : " + message + ", port :" + port;
}
}
-
接下来重新启动原有实例,并再启动一个
sca-nacos-discovery-provide
的实例, 如下所示:
-
再次请求 http://localhost:9033/test , 会交替显示如下信息:
Hello Nacos Discovery Provider : !^@^! , port :8081
Hello Nacos Discovery Provider : !^@^! , port :9030
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源码地址:
github地址: https://github.com/fxbin/sca
码云地址 : https://gitee.com/fxbin/sca
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