openfeign远程调用

使用技术：nacos注册表、openfeign远程调用

一、简单远程调用，适合少量服务调用调用少量接口

1.1、创建一个被调用服务user

将服务注册到nacos注册表

依赖：注意nacos版本号与springboot版本号是否搭配，不搭配启动报错

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--nacos依赖-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2021.0.1.0</version>
        </dependency>
        <!--nacos配置文件依赖，不在nacos配置的不需要引入-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
            <version>2021.0.1.0</version>
        </dependency>

配置文件

server:
  port: 8080
spring:
  application:
    name: user
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848    #IP地址

写请求接口代码

    @GetMapping("/find")
    public String findUser(@RequestParam String name){
        return name;
    }

1.2、创建一个open-feign-user服务远程调用user服务

添加nacos与openfeign依赖：注意nacos版本号与springboot版本号是否搭配，不搭配启动报错

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <!--远程调用依赖-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <version>3.1.5</version>
        </dependency>
        <!--nacos依赖-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
            <version>2021.0.1.0</version>
        </dependency>
        <!--高版本openfeign需要添加，否则报错-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-loadbalancer</artifactId>
            <version>3.1.3</version>
        </dependency>

配置文件

server:
  port: 8081
spring:
  application:
    name: open
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848    #IP地址

启动类加注解：@EnableFeignClients

@SpringBootApplication
@EnableFeignClients
public class OpenFeignUserApplication {
 
    public static void main(String[] args) {
        SpringApplication.run(OpenFeignUserApplication.class, args);
    }
 
}

添加调用接口：user指调注册到nacos的服务

package com.example.openfeignuser.openfeign;
 
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
 
@FeignClient(value = "user")
public interface UserClient {
    /**调用user服务的findUser接口*/
    @GetMapping("/user/find")
    String findUser(@RequestParam("name") String name);
}

在需要调用的类注入接口进行调用

package com.example.openfeignuser.service.impl;
 
import com.example.openfeignuser.openfeign.UserClient;
import com.example.openfeignuser.service.OpenFeignService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
 
@Service
public class OpenFeignServiceImpl implements OpenFeignService {
    @Autowired
    private UserClient userClient;
 
    @Override
    public String findUser(String name) {
        return userClient.findUser(name);
    }
}

二、抽取便捷多服务远程调用，适合多服务调用多个接口

不存在多个服务多个接口多调用不需要

后续更新