Feign使用

目录

 

1. 概述

2. feign使用步骤

2.1添加pom(消费端)

2.2在公共api处新增

2.3在feign消费端修改Controller

2.4在feign消费端修改启动类,新增相关注解 @EnableFeignClients和@ComponentScan

补充: feign集成了ribbon,默认使用轮询实现负载均衡

3. 消费服务端方式

3.1 feign 通过接口方式调用Rest服务

3.2 使用Ribbon + RestTemplate调用服务

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1. 概述

feign是一个声明式的webservice客户端,使得编写服务客户端变得非常容易.

主要要创建一个接口,然后在上面添加注解即可.

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2. feign使用步骤

2.1添加pom(消费端)

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>

2.2在公共api处新增

package com.jsp.springcloud.servicecloudapi.service;

import com.jsp.springcloud.servicecloudapi.model.Dept;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import java.util.List;

@FeignClient(value = "SERVICECLOUD-DEPT")
public interface DeptClientService {

    @RequestMapping(value = "/dept/get/{id}", method = RequestMethod.GET)
    Dept get(@PathVariable("id") long id);

    @RequestMapping(value = "/dept/getAll", method = RequestMethod.GET)
    List<Dept> getAll();

    @RequestMapping(value = "/dept/add", method = RequestMethod.POST)
    boolean add(Dept dept);


}

2.3在feign消费端修改Controller

package com.jsp.springcloud.servicecloudconsumedeptfeign.controller;

import com.jsp.springcloud.servicecloudapi.model.Dept;
import com.jsp.springcloud.servicecloudapi.service.DeptClientService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class DeptController_Consumer {

    @Autowired
    private DeptClientService deptService;

    @RequestMapping(value = "/dept/add")
    public boolean add(Dept dept) {
        return this.deptService.add(dept);
    }

    @RequestMapping(value = "/dept/get/{id}")
    public Dept get(@PathVariable("id") Long id) {
        return this.deptService.get(id);
    }

    @RequestMapping(value = "/dept/list")
    public List<Dept> list() {
        return this.deptService.getAll();
    }
}

2.4在feign消费端修改启动类,新增相关注解 @EnableFeignClients和@ComponentScan

package com.jsp.springcloud.servicecloudconsumedeptfeign;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.ComponentScan;

@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients(basePackages = {"com.jsp.springcloud"})
@ComponentScan("com.jsp.springcloud")
public class ServicecloudConsumeDeptFeignApplication {

    public static void main(String[] args) {
        SpringApplication.run(ServicecloudConsumeDeptFeignApplication.class, args);
    }

}

补充: feign集成了ribbon,默认使用轮询实现负载均衡

3. 消费服务端方式

3.1 feign 通过接口方式调用Rest服务

请求发送给Eureka服务器,通过Feign找到服务接口,服务调用时候融合了ribbon,所以支持负载均衡

3.2 使用Ribbon + RestTemplate调用服务