OpenFeign(1)---＞使用OpenFeign

1、在前面我们讲解了Ribbon,我们使用ribbon的方式主要是自己是同RestTemplate 来进行远程请求的调用，代码如下：

    @GetMapping("userGetOrderById")public OrderDto userGetOrderById(@RequestParam("orderId") String orderId){//使用具备负载均衡功能的RestTemplate进行http服务调用ResponseEntity<OrderDto> forEntity = restTemplate.getForEntity("http://order-service/getOrderById?orderId=" + orderId, OrderDto.class);return forEntity.getBody();}

     这种方式在小项目中我们这样写确实也没啥问题，但是如果我们的接口特别多，这种方式就比较鸡肋了，因此spring cloud 为我们提供了OpenFeign来解决这个问题，接下来我们来看看如何使用openFeign？

2、使用OpenFeign

       2.1、项目结构：

        2.2、order-api 项目信息：

                  pom.xml文件：

    <parent><artifactId>spring-cloud-openfeign</artifactId><groupId>com.wzy</groupId><version>0.0.1-SNAPSHOT</version></parent><modelVersion>4.0.0</modelVersion><artifactId>order-api</artifactId><dependencies><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-openfeign</artifactId></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency></dependencies>

                定义的FeignClient : 

      @FeignClient("order-service")@RequestMapping("order")public interface OrderFeignClient {@PostMapping("save")boolean saveOrder(@RequestBody OrderDto orderDto);@GetMapping("findAll")Collection <OrderDto> findAll();}

         2.3、order-service 项目信息：

               pom.xml文件：

    <parent><artifactId>spring-cloud-openfeign</artifactId><groupId>com.wzy</groupId><version>0.0.1-SNAPSHOT</version></parent><modelVersion>4.0.0</modelVersion><artifactId>order-service</artifactId><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-eureka-client</artifactId></dependency><dependency><groupId>com.wzy</groupId><artifactId>order-api</artifactId><version>${project.version}</version></dependency></dependencies>

         OrderController提供服务：

@RestController
@RequestMapping("order")
public class OrderController {public static  final Map<String,OrderDto> datas = new ConcurrentHashMap<>();@PostMapping("save")public boolean saveOrder(@RequestBody OrderDto orderDto){datas.put(orderDto.getId(), orderDto);return true;}@GetMapping("findAll")public Collection<OrderDto> findAll(){try {Thread.sleep(800L);} catch (InterruptedException e) {e.printStackTrace();}return datas.values();}
}

      启动类：    

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

       配置文件application.properties：

server.port=7070
spring.application.name=order-serviceeureka.client.service-url.defaultZone=http://localhost:9090/eureka
eureka.client.registry-fetch-interval-seconds=10

     2.4、user-service 项目信息：

              pom.xml文件：

   <parent><artifactId>spring-cloud-openfeign</artifactId><groupId>com.wzy</groupId><version>0.0.1-SNAPSHOT</version></parent><modelVersion>4.0.0</modelVersion><artifactId>user-service</artifactId><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-eureka-client</artifactId></dependency><dependency><groupId>com.wzy</groupId><artifactId>order-api</artifactId><version>${project.version}</version></dependency></dependencies>

           调用order-service 的方式：

@RestController
@RequestMapping("user")
public class UserController {@Autowiredprivate OrderFeignClient orderFeignClient;@PostMapping("saverOrder")public boolean saveOrder(@RequestBody OrderDto orderDto){return orderFeignClient.saveOrder(orderDto);}@GetMapping("getAllOrder")public Collection <OrderDto> getAllOrder(){return orderFeignClient.findAll();}
}

           启动类：

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients(clients = {OrderFeignClient.class})
public class UserService {public static void main(String[] args) {SpringApplication.run(UserService.class, args);}
}

       配置文件application.properties：

spring.application.name=user-service
server.port=8080
eureka.client.service-url.defaultZone=http://localhost:9090/eureka
eureka.client.instance-info-replication-interval-seconds=10#设置feign的请求超时时间为1秒
feign.client.config.default.read-timeout=1000
ribbon.ReadTimeout=1000

以上就是使用OpenFeign的代码，使用还是很简单的，接下来的文章我们将剖析其原理。