一、简单介绍OpenFeign 是⼀个声明式的 Web Service 客户端. 它让微服务之间的调用变得更简单,类似controller 调用 service, 只需要创建⼀个接口然后添加注解即可使用 OpenFeign.二、使用方法这里的项目是在实现 nacos 基础上实现的(可以看之前nacos的用法)1、在服务消费者order-servicepom 文件中引入 OpenFeign 依赖dependency groupIdorg.springframework.cloud/groupId artifactIdspring-cloud-starter-openfeign/artifactId /dependency2、添加注解在服务消费者 order-service的启动类添加注解 EnableFeignClients ,开启OpenFeign的功能.package com.linzhixin.order; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.openfeign.EnableFeignClients; EnableFeignClients SpringBootApplication public class OrderServiceApplication { public static void main(String[] args) { SpringApplication.run(OrderServiceApplication.class, args); } }3、编写 OpenFeign 的客户端pimport org.springframework.cloud.openfeign.FeignClient; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; FeignClient(value product-service, path /product) public interface ProductApi { RequestMapping(/{productId}) ProductInfo getProductById(PathVariable(productId) Integer productId); }4、远程调用Autowired private ProductApi productApi; public OrderInfo selectOrderById(Integer orderId) { OrderInfo orderInfo orderMapper.selectOrderById(orderId); ProductInfo productInfo productApi.getProductById(orderInfo.getProductId()); orderInfo.setProductInfo(productInfo); return orderInfo; }5、访问接口测试三、最佳使用方法使用方法的改进 -- Feign 继承方式参考文档https://docs.spring.io/spring-cloud-openfeign/reference/spring-cloud-openfeign.html#spring-cloud-feign-inheritance1、创建一个 Module(接口可以放在⼀个公共的Jar包里, 供服务提供方和服务消费方使用)这里包含 productInfo 的对象可以把 order-service 和 product-service 里面的 productInfo 删了通过引入打包的 product-api 来映入 product-api 中的 productInfo2、引入依赖dependencies dependency groupIdorg.springframework.boot/groupId artifactIdspring-boot-starter-web/artifactId /dependency dependency groupIdorg.springframework.cloud/groupId artifactIdspring-cloud-starter-openfeign/artifactId /dependency /dependencies3、编写接口package com.linzhixin.product.api; import com.linzhixin.product.model.ProductInfo; import org.springframework.cloud.openfeign.SpringQueryMap; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; public interface ProductInterface { RequestMapping(/{productId}) ProductInfo getProductById(PathVariable(productId) Integer productId); RequestMapping(/p1) String p1(RequestParam(id) Integer id); RequestMapping(/p2) String p2(RequestParam(id) Integer id, RequestParam(name) String name); RequestMapping(/p3) String p3(SpringQueryMap ProductInfo productInfo); RequestMapping(/p4) String p4(RequestBody ProductInfo productInfo); }4、打 Jar 包通过右侧 maven 打 包5、服务提供方实现接口ProductInterfacepackage com.linzhixin.product.controller; import com.linzhixin.product.api.ProductInterface; import com.linzhixin.product.model.ProductInfo; import com.linzhixin.product.service.ProductService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; RequestMapping(/product) RestController public class ProductController implements ProductInterface { Autowired private ProductService productService; RequestMapping(/{productId}) public ProductInfo getProductById(PathVariable(productId) Integer productId) { System.out.println(收到请求,Id:productId); return productService.selectProductById(productId); } RequestMapping(/p1) public String p1(Integer id){ return p1接收到参数:id; } RequestMapping(/p2) public String p2(Integer id,String name){ return p2接收到参数,id:id ,name:name; } RequestMapping(/p3) public String p3(ProductInfo productInfo){ return 接收到对象, productInfo:productInfo; } RequestMapping(/p4) public String p4(RequestBody ProductInfo productInfo){ return 接收到对象, productInfo:productInfo; } }6、服务消费方继承 ProductInterface 接口package com.linzhixin.order.api; import com.linzhixin.product.api.ProductInterface; import org.springframework.cloud.openfeign.FeignClient; FeignClient(value product-service, path /product) public interface ProductApi extends ProductInterface { }7、测试四、最佳使用方法使用方法的改进 -- Feign 抽取方式这里还是在二、使用方法上改进1、创建一个 product-api module这里包含 productInfo 的对象可以把 order-service 里面的 productInfo 删了通过引入打包的 product-api 来映入 product-api 中的 productInfo2、为 product-api 引入依赖dependencies dependency groupIdorg.springframework.boot/groupId artifactIdspring-boot-starter-web/artifactId /dependency dependency groupIdorg.springframework.cloud/groupId artifactIdspring-cloud-starter-openfeign/artifactId /dependency /dependencies3、编写 ProductApipackage com.linzhixin.product.api; import com.linzhixin.product.model.ProductInfo; import org.springframework.cloud.openfeign.FeignClient; import org.springframework.cloud.openfeign.SpringQueryMap; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestBody; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestParam; FeignClient(value product-service, path /product) public interface ProductApi { RequestMapping(/{productId}) ProductInfo getProductById(PathVariable(productId) Integer productId); RequestMapping(/p1) String p1(RequestParam(id) Integer id); RequestMapping(/p2) String p2(RequestParam(id) Integer id, RequestParam(name) String name); RequestMapping(/p3) String p3(SpringQueryMap ProductInfo productInfo); RequestMapping(/p4) String p4(RequestBody ProductInfo productInfo); }4、通过Maven 打 product-api module 的 jar 包5、服务消费方使用 product-api1、删除 order-service 里面的 Product-Api ProductInfo2、引入依赖dependency groupIdcom.linzhixin/groupId artifactIdproduct-api/artifactId version1.0-SNAPSHOT/version /dependency注意要修改报错的地方改路径3、指定需要加载的 Feign 客户端package com.linzhixin.order; import com.linzhixin.product.api.ProductApi; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.openfeign.EnableFeignClients; EnableFeignClients(clients {ProductApi.class}) SpringBootApplication public class OrderServiceApplication { public static void main(String[] args) { SpringApplication.run(OrderServiceApplication.class, args); } }6、测试
