Feign:使用接口方式调用服务

创建一个新的消费者模块并导入依赖

<?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"><parent><artifactId>springcloud</artifactId><groupId>com.kuang</groupId><version>1.0-SNAPSHOT</version></parent><modelVersion>4.0.0</modelVersion><artifactId>springcloud-consumer-dept-feign</artifactId><properties><maven.compiler.source>8</maven.compiler.source><maven.compiler.target>8</maven.compiler.target></properties><!--  消费者：实体类+web  不需要连接数据库，跟前端打交道的  --><dependencies><!-- Ribbon 集成      --><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-feign</artifactId><version>1.4.6.RELEASE</version></dependency><!-- Ribbon 集成      --><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-ribbon</artifactId><version>1.4.6.RELEASE</version></dependency><!--    Eureka    --><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-eureka</artifactId><version>1.4.6.RELEASE</version></dependency><dependency><groupId>com.kuang</groupId><artifactId>springcloud-api</artifactId><version>1.0-SNAPSHOT</version></dependency><!--    web 支持    --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!--     热部署   --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-devtools</artifactId></dependency></dependencies></project>

修改API模块里的

实体类

package com.kuang.springcloud.pojo;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import lombok.experimental.Accessors;import java.io.Serializable;
@NoArgsConstructor
@Accessors(chain = true)//链式写法
@Data
//实现序列化  实体类  ORM映射  mysql--dept
public class Dept implements Serializable {private Long deptno;//主键private String dname;//这个数据库存在哪个数据库字段。~微服务，一个服务对应一个数据库，同一个信息可能存在不同的数据库private String db_source;public Dept(String dname) {this.dname = dname;}/*** 链式写法：*Dept dept = new Dept();* dept.setDeptNo(11).setDbane('sss').setDb_source("001");*/}

业务层接口，Feign基于接口实现的

package com.kuang.springcloud.service;import com.kuang.springcloud.pojo.Dept;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.stereotype.Component;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;import java.util.List;@Component
@FeignClient(value = "SPRINGCLOUD-PROVIDER-DEPT")
public interface DeptClientService {@GetMapping("/dept/get/{id}")Dept queryById(@PathVariable("id") Long id);@GetMapping("/dept/list")List<Dept> queryAll();@PostMapping("/dept/add")String addDept(Dept dept);}

消费者Feign服务

Controller

package com.kuang.springcloud.controller;import com.kuang.springcloud.pojo.Dept;
import com.kuang.springcloud.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 org.springframework.web.client.RestTemplate;import java.util.List;@RestController
public class DeptConsumerController {//理解：消费者，不应该有Service层//模板有很多方法供我们去使用//注入过来
//(String url, 实体：map, Class<T> responseType, Object... uriVariables)
//(url,实体,map,Class<T> responseType 返回值类型)  三个参数  五种请求方式//Ribbon 我们这里的地址，应该是一个变量，通过服务名字来访问// private static final String REST_URL_PREFIX="http://localhost:8001";@Autowiredprivate DeptClientService service;@RequestMapping("/consumer/dept/get/{id}")public Dept get(@PathVariable("id")Long id){return service.queryById(id);}@RequestMapping("/consumer/dept/add")public String add(Dept dept){return service.addDept(dept);}@RequestMapping("/consumer/dept/list")public List<Dept> list(){return service.queryAll();}}

主启动类加两个注解

package com.kuang.springcloud;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.ribbon.RibbonClient;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.ComponentScan;//Ribbon和Eureka 整合以后 ，客户端可以直接调用，不用关心IP地址和端口号~
@SpringBootApplication
@EnableEurekaClient
@EnableFeignClients(basePackages = "com.kuang.springcloud")public class FeignDeptConsumer80 {public static void main(String[] args) {SpringApplication.run(FeignDeptConsumer80.class,args);}
}