【Feign】 基于 Feign 远程调用、 自定义配置、性能优化、实现 Feign 最佳实践

String url = "http://userservice/user/" + order.getUserId();User user = restTemplate.getForObject(url, User.class);

<!--feign客户端依赖--><dependency>    <groupId>org.springframework.cloud</groupId>    <artifactId>spring-cloud-starter-openfeign</artifactId></dependency>

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

@FeignClient("userservice")public interface UserClient {    @GetMapping("/user/{id}")    User findById(@PathVariable("id") Long id);}

@Servicepublic class OrderService {    @Autowired    private OrderMapper orderMapper;    @Autowired    private UserClient userClient;    public Order queryOrderById(Long orderId) {        // 1.查询订单        Order order = orderMapper.findById(orderId);        //2.用feign远程调用        User user = userClient.findById(order.getUserId());        //封装user到order        order.setUser(user);        // 4.返回        return order;    }}

feign:  client:    config:      default:  # 默认全局配置        loggerLevel: FULL # 打开全部日志

feign:  client:    config:      userservice:  # 针对 userservice 服务        loggerLevel: FULL # 打开全部日志

public class FeignClientConfiguration {    @Bean    public Logger.Level logLevel() {        return Logger.Level.BASIC;    }}

@EnableFeignClients(defaultConfiguration = FeignClientConfiguration.class)

@FeignClient(value = "userservice",configuration = FeignClientConfiguration.class)

<!--引入HttpClient依赖--><dependency>    <groupId>io.github.openfeign</groupId>    <artifactId>feign-httpclient</artifactId></dependency>

feign:  client:    config:      default:  # 默认全局配置        loggerLevel: BASIC  # 日志级别，BASIC是最基本的请求和响应  httpclient:    enabled: true # 支持HttpClient的开关    max-connections: 200 # 最大连接数    max-connections-per-route: 50 # 单个路径最大连接数

<dependency>  <groupId>org.springframework.cloud</groupId>  <artifactId>spring-cloud-starter-openfeign</artifactId>  <version>2.2.1.RELEASE</version></dependency>>

<!--引入统一feign-api--><dependency>    <groupId>cn.itcast.demo</groupId>    <artifactId>feign-api</artifactId>    <version>1.0</version></dependency>

import cn.itcast.feign.pojo.User;import cn.itcast.feign.clients.*;

@EnableFeignClients(basePackages = "cn.feign.clients")

@EnableFeignClients(clients = UserClient.class)