第五章 SpringCloud 使用Feign调用服务

本章节完整源代码地址：https://github.com/kwang2003/springcloud-study-ch05.git

1.项目概要介绍

在第三章和第四章的学习中，我们已经掌握了通过RestTemplate负载均衡机制来调用注册中心中的服务，除了RestTemplate外，SpringCloud还提供了另一个强大的组件Feign，这让客户端开发人员的编码更加简洁高效。

本章节的代码将以第四章的完整代码为基础进行feign改造实现

https://github.com/kwang2003/springcloud-study-ch04.git

2.服务调用者user-service

feign是工作在服务调用者一方的，因此只要改造user-service工程，将其中通过RestTemplate调用message服务的部分改造成feign即可

a)添加Feign依赖

springcloud-user工程

<dependency>

<groupId>org.springframework.cloud</groupId>

<artifactId>spring-cloud-starter-feign</artifactId>

</dependency>

b)项目中启用Feign

在UserApplication主函数类上添加@EnableFeignClients

c)编写FeignClient服务

新增一个接口com.pachiraframework.springcloud.user.service.MessageService

接口使用@FeignClients注解进行标注，注解中接受一个参数，标示出客户端要调用的注册中心中服务的id，用于创建Ribbon负载均衡器

接口中的方法和服务提供者中的定义保持一致,注意，这里我们调用的是SmsController中的send2方法，因为这个方法的接收参数添加了@RequestBody参数

package com.pachiraframework.springcloud.user.service;

import java.util.Map;

import org.springframework.cloud.netflix.feign.FeignClient;

import org.springframework.http.ResponseEntity;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RequestMethod;

import com.pachiraframework.springcloud.user.controller.UserController.SmsSendResponse;

import lombok.Data;

@FeignClient("message-service")

public interface MessageService {

@RequestMapping(method=RequestMethod.POST,value="/message/sms/send2")

public ResponseEntity<SmsSendResponse> send(SmsSendRequest request);

@Data

public static class SmsSendRequest {

/**

* 短信模版ID

*/

private String templateId;

/**

* 要发送的手机号

*/

private String mobile;

/**

* 模版中携带的参数信息

*/

private Map<String, Object> params;

}

}

d)调用方UserController改造

新增一个regist/sms2方法，用于和先前的基于RestTemplate方法调用区分开

具体代码内容如下

package com.pachiraframework.springcloud.user.controller;

import java.util.HashMap;

import java.util.Map;

import java.util.Random;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.http.HttpEntity;

import org.springframework.http.HttpHeaders;

import org.springframework.http.MediaType;

import org.springframework.http.ResponseEntity;

import org.springframework.util.LinkedMultiValueMap;

import org.springframework.util.MultiValueMap;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import org.springframework.web.client.RestTemplate;

import com.pachiraframework.springcloud.user.service.MessageService;

import com.pachiraframework.springcloud.user.service.MessageService.SmsSendRequest;

import lombok.Data;

import lombok.extern.slf4j.Slf4j;

@Slf4j

@RestController

@RequestMapping("/user/")

public class UserController {

@Autowired

private RestTemplate restTemplate;

@Autowired

private MessageService messageService;

@RequestMapping(value= {"regist/sms"})

public ResponseEntity<SmsSendResponse> sms(String mobile){

Random random = new Random();

int next = random.nextInt(10000000);

String code = ""+(10000000-next);

ResponseEntity<SmsSendResponse> response = doSend(mobile, code);

return response;

}

public ResponseEntity<SmsSendResponse> doSend(String mobile,String code) {

final String sendUrl = "http://message-service/message/sms/send";

HttpHeaders headers = new HttpHeaders();

headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

MultiValueMap<String, String> map= new LinkedMultiValueMap<String, String>();

map.add("mobile", mobile);

map.add("templateId", "CHECK_CODE");

map.add("params['code']", code);

log.info("发送参数：{}",map);

HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<MultiValueMap<String, String>>(map, headers);

ResponseEntity<SmsSendResponse> response = restTemplate.postForEntity(sendUrl, request, SmsSendResponse.class);

return response;

}

@RequestMapping(value= {"regist/sms2"})

public ResponseEntity<SmsSendResponse> sms2(String mobile){

Random random = new Random();

int next = random.nextInt(10000000);

String code = ""+(10000000-next);

ResponseEntity<SmsSendResponse> response = doSendFeign(mobile, code);

return response;

}

public ResponseEntity<SmsSendResponse> doSendFeign(String mobile,String code) {

SmsSendRequest request = new SmsSendRequest();

request.setMobile(mobile);

request.setTemplateId("CHECK_CODE");

Map<String, Object> params = new HashMap<>();

params.put("code", code);

request.setParams(params);

return messageService.send(request);

}

@Data

public static class SmsSendResponse {

/**

* 返回消息

*/

private String message;

/**

* 返回状态码

*/

private String code;

}

}

3.测试改造结果

运行UserApplication程序，访问

http://localhost:8082/user/regist/sms2?mobile=1234567895