Spring Cloud遠端調用之OpenFeign

Feign是一個聲明式的僞RPC（Feign英文意思為“假裝，僞裝，變形”）的REST用戶端，它用了基于接口的注解方式，可以以Java接口注解的方式調用Http請求，進而将請求子產品化。Feign被廣泛應用在Spring Cloud的解決方案中，是學習基于Spring Cloud微服務架構不可或缺的重要元件。

使用

1、添加依賴

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

2、啟動類添加@EnableFeignClients注解

3、定義注解接口

@FeignClient注解裡面的user-server為調用服務名

package demo.newsweb.controller;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;

@FeignClient("user-server")
public interface UserControllerFeign {

    @GetMapping("/user/login")
    String login(@RequestParam("user") String user, @RequestParam("pwd") String pwd);
}

           

4、使用注解接口遠端調用

package demo.newsweb.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@RequestMapping("user")
public class UserController {

    @Autowired
    private UserControllerFeign userControllerFeign;

    @GetMapping("/login")
    public String login(String user, String pwd) {
        return  userControllerFeign.login(user, pwd);
    }
}

           

特性

開啟Gzip壓縮

# 請求開啟壓縮
feign.compression.request.enabled=true
# 最小壓縮大小（字元），低于這個值則不壓縮
feign.compression.request.min-request-size=2048
# 響應開啟壓縮
feign.compression.response.enabled=true
# 壓縮類型 "text/xml", "application/xml", "application/json"
feign.compression.request.mime-types=text/xml,application/xml,application/json
           

Feign日志配置

1、配置日志輸出級别

# 日志級别
logging.level.[demo.newsweb.controller.UserControllerFeign]=debug
           

2、配置日志輸出方式

FULL為輸出全部資訊。

package demo.newsweb.controller;

import feign.Logger;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class FeginLogConfig {

    @Bean
    Logger.Level feignLogger() {
        return Logger.Level.FULL;
    }
}
           

3、Feign接口注解@FeignClient加入configuration = FeginLogConfig.class使用設定的日志輸出方式

package demo.newsweb.controller;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;

@FeignClient(value = "user-server",configuration = FeginLogConfig.class)
public interface UserControllerFeign {

    @GetMapping("/user/login")
    String login(@RequestParam("user") String user, @RequestParam("pwd") String pwd);
}

           

輸出資訊如下

替換預設的底層通信

底層通信預設是URLConnection，可替換成性能更好的okHttp

添加依賴

<dependency>
    <groupId>io.github.openfeign</groupId>
     <artifactId>feign-okhttp</artifactId>
 </dependency>
           

添加配置啟用

feign.httpclient.enabled=false
feign.okhttp.enabled=true