springboot+nacos+feign的简单实例

feign的简单实例

一、什么是feign

Feign是Netflix开发的声明式(目前由Spring在维护)、模板化的HTTP客户端， Feign可以帮助我们更快捷、优雅地调用HTTP API。

简单的来说就是一个远程调用服务的框架/工具，让开发者以更少耦合更少代码更快更兼容的方法进行远程服务调用

二、Feign功能

• 可插拔的注解支持，包括Feign注解和JAX-RS注解;
• 与Ribbon负载均衡器、Hystrix或Sentinel熔断器无缝集成。
• 支持可插拔的HTTP编码器和解码器;
• 支持HTTP请求和响应的压缩。

三、基本使用

创建spring-cloud-feign项目

项目结构

父：spring-cloud-feign

子模块1：provider

子模块2：consumer

添加依赖

整个项目的依赖（由于全写在了父pom中，所以子依赖无需添加新的依赖）

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-alibaba-nacos-discovery</artifactId>
            <version>2.2.0.RELEASE</version>
        </dependency>
           

提供者：provider

1.提供者的application.yml

server:
  port: 8180 //服务器端口
spring:
  application:
    name: test-feign-provider //提供者注册的服务名称
  cloud:
    nacos:
      discovery:
        server-addr: http://（nacos注册中心ip):8848
        cluster-name: ${spring.application.name} //提供者注册的服务名称
           

2.提供者的Application

package com.smart.provider;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
/**
 * 添加@EnableDiscoveryClient注册服务
 */
@SpringBootApplication
@EnableDiscoveryClient 
public class ProviderApplication {
    public static void main(String[] args) {
        SpringApplication.run(ProviderApplication.class);
    }
}

           

3.提供者的Controller

package com.smart.provider.controller;


import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping
public class TestController {

    @RequestMapping(value = "/getStr",method = RequestMethod.GET)
    public String getStr(@RequestParam("stats") Integer stats){
        if (stats==1){
            return "对了";
        } else {
            return "错了";
        }
    }
}

           

注意：@RequestParam(“stats”)一定要加上，否则会报错

服务消费者：consumer

1.消费者的yml文件：

server:
  port: 8083
spring:
  application:
    name: service-consumer
  cloud:
    nacos:
      discovery:
        server-addr: http://(nacos注册中心ip):8848
        cluster-name: ${spring.application.name}
           

2.消费者的application

package com.smart.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;
/**
 * 通过@EnableFeignClients注解开启对FeignClients的扫描
 */
@EnableFeignClients
@EnableDiscoveryClient
@SpringBootApplication
public class ConsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(ConsumerApplication.class);
    }
}

           

3.消费者的dao层

package com.smart.consumer.dao;


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

@FeignClient("test-feign-provider")
public interface TestFeign {
    @RequestMapping(value = "/getStr",method = RequestMethod.GET)
    String getStr(@RequestParam("stats") Integer stats);
}

           

4.消费者的service层和impl

package com.smart.consumer.service;

public interface TestFeignService {

    String getTestStr(Integer stats);
}

           

package com.smart.consumer.service.impl;

import com.smart.consumer.dao.TestFeign;
import com.smart.consumer.service.TestFeignService;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;

@Service
public class TestFeignServiceImpl implements TestFeignService {

    @Resource
    TestFeign testFeign;

    @Override
    public String getTestStr(Integer stats) {
        return testFeign.getStr(stats);
    }
}

           

5.消费者的Controller层

package com.smart.consumer.controller;


import com.smart.consumer.service.TestFeignService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

@RestController
public class TestFeignController {
    @Resource
    TestFeignService testFeignService;

    @GetMapping("/getStr")
    public String getStr(Integer stats){
        String testStr = testFeignService.getTestStr(stats);
        return testStr;
    }
}

           

测试

分别注册两个服务到注册中心nacos后，用postman测试