22. Spring cloud - using feign to call service interface? Java version of spring cloud + springboot + uniapp + Vue B2B2C micro Service Mall micro service e-commerce live delivery source code

Springcloud Cloud Architecture 2021-04-16 18:33:06
spring cloud using feign service


JAVA How to do interface calls in a project ?

1)Httpclient

HttpClient yes Apache Jakarta Common Sub projects under , To provide efficient 、 Abreast of the times 、 Feature rich support Http Client programming toolkit for protocol , And it supports HTTP The latest version of the agreement and recommendations .

HttpClient Compared with tradition JDK Self contained URLConnection, Improved ease of use and flexibility , Make the client send HTTP It's easier to ask , Improved development efficiency .

2)Okhttp

An open source project to handle network requests , It's the most popular lightweight framework in Android , from Square The company contributed , Used in substitution HttpUrlConnection and Apache HttpClient.OkHttp Have a simple API、 Efficient performance , And support a variety of protocols (HTTP/2 and SPDY).

3)HttpURLConnection

HttpURLConnection yes  Java  Standard class , It is inherited from URLConnection, Can be used to send GET request 、POST request .HttpURLConnection It's complicated to use , Unlike HttpClient That's easy to use .

4)RestTemplate

RestTemplate yes  Spring  Provided for access Rest Client of service ,RestTemplate Provides a variety of convenient remote access HTTP Method of service , Can greatly improve the writing efficiency of the client .

The above are the most common methods to call the interface , The method we're going to introduce next is simpler than the one above 、 convenient , It is Feign.

Feign It's a declarative one REST client , It can make REST It's easier to call .Feign For HTTP Requested template , By writing simple interfaces and inserting annotations , You can define HTTP Requested parameters 、 Format 、 Address and other information .

and Feign It'll be a complete agent HTTP request , We only need to call it like a method to complete the service request and related processing .

Spring Cloud  Yes Feign It was packaged , To support SpringMVC Standard notes and HttpMessageConverters.Feign It can be done with Eureka and Ribbon Combined to support load balancing .

stay Spring Cloud In the integration Feign

stay Spring Cloud In the integration Feign The steps are quite simple , First of all, join Feign Dependence , The code is as follows .

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

Add... To the startup class @EnableFeignClients annotation , If your Feign The interface definition is not in the same package name as your startup class , You also need to make a package name to scan @EnableFeignClients(basePackages=“com.fangjia.api.client”), The code is as follows .

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients(basePackages = "com.fangjia.api.client")
public class FshSubstitutionServiceApplication {
public static void main(String[] args) {
SpringApplication.run(FshSubstitutionServiceApplication.class, args);
}
}

Use Feign Call interface

Define a Feign The client of , In the form of interfaces , The code is as follows .

@FeignClient(value = "eureka-client-user-service")
public interface UserRemoteClient {
@GetMapping("/user/hello")
String hello();
}

First of all, let's look at the interface @FeignClient annotation . This annotation ID is currently a Feign The client of ,value Property is the corresponding service name , Which service interface do you need to call .

When defining a method, you can directly copy the definition of the interface , Of course, there is another way , That is to extract the interface and define it separately , And then in Controller Implementation interface in .

The interface is also implemented in the calling client , So as to achieve the purpose of interface sharing . My practice here is not shared , That is to create a separate API Client Public projects in China , Convention based patterns , Every time you write an interface, you need to write a calling Client, Make it public in the back jar, So no matter which project needs to call the interface , Just bring in a common interface SDK jar that will do , There's no need to redefine it .

After definition, it can be directly injected through UserRemoteClient To call , It's like calling local methods for developers .

Next, use Feign To call /user/hello Interface , The code is as follows .

@Autowired
private UserRemoteClient userRemoteClient;
@GetMapping("/callHello")
public String callHello() {
//return restTemplate.getForObject("http://localhost:8083/house/hello",String.class);
//String result = restTemplate.getForObject("http://eureka-client-user-service/user/hello",String.class);
String result = userRemoteClient.hello();
System.out.println(" The results :" + result);
return result;
}

By comparing with the commented code, we can see that , The way we call it is getting simpler and simpler , From the designated address , Go back through Eureka To call , Up to now, it can be called directly by defining the interface .

Recommended cloth type Micro Service Mall

版权声明
本文为[Springcloud Cloud Architecture]所创,转载请带上原文链接,感谢
https://javamana.com/2021/04/20210416163835433n.html

  1. 【计算机网络 12(1),尚学堂马士兵Java视频教程
  2. 【程序猿历程,史上最全的Java面试题集锦在这里
  3. 【程序猿历程(1),Javaweb视频教程百度云
  4. Notes on MySQL 45 lectures (1-7)
  5. [computer network 12 (1), Shang Xuetang Ma soldier java video tutorial
  6. The most complete collection of Java interview questions in history is here
  7. [process of program ape (1), JavaWeb video tutorial, baidu cloud
  8. Notes on MySQL 45 lectures (1-7)
  9. 精进 Spring Boot 03:Spring Boot 的配置文件和配置管理,以及用三种方式读取配置文件
  10. Refined spring boot 03: spring boot configuration files and configuration management, and reading configuration files in three ways
  11. 精进 Spring Boot 03:Spring Boot 的配置文件和配置管理,以及用三种方式读取配置文件
  12. Refined spring boot 03: spring boot configuration files and configuration management, and reading configuration files in three ways
  13. 【递归,Java传智播客笔记
  14. [recursion, Java intelligence podcast notes
  15. [adhere to painting for 386 days] the beginning of spring of 24 solar terms
  16. K8S系列第八篇(Service、EndPoints以及高可用kubeadm部署)
  17. K8s Series Part 8 (service, endpoints and high availability kubeadm deployment)
  18. 【重识 HTML (3),350道Java面试真题分享
  19. 【重识 HTML (2),Java并发编程必会的多线程你竟然还不会
  20. 【重识 HTML (1),二本Java小菜鸟4面字节跳动被秒成渣渣
  21. [re recognize HTML (3) and share 350 real Java interview questions
  22. [re recognize HTML (2). Multithreading is a must for Java Concurrent Programming. How dare you not
  23. [re recognize HTML (1), two Java rookies' 4-sided bytes beat and become slag in seconds
  24. 造轮子系列之RPC 1:如何从零开始开发RPC框架
  25. RPC 1: how to develop RPC framework from scratch
  26. 造轮子系列之RPC 1:如何从零开始开发RPC框架
  27. RPC 1: how to develop RPC framework from scratch
  28. 一次性捋清楚吧,对乱糟糟的,Spring事务扩展机制
  29. 一文彻底弄懂如何选择抽象类还是接口,连续四年百度Java岗必问面试题
  30. Redis常用命令
  31. 一双拖鞋引发的血案,狂神说Java系列笔记
  32. 一、mysql基础安装
  33. 一位程序员的独白:尽管我一生坎坷,Java框架面试基础
  34. Clear it all at once. For the messy, spring transaction extension mechanism
  35. A thorough understanding of how to choose abstract classes or interfaces, baidu Java post must ask interview questions for four consecutive years
  36. Redis common commands
  37. A pair of slippers triggered the murder, crazy God said java series notes
  38. 1、 MySQL basic installation
  39. Monologue of a programmer: despite my ups and downs in my life, Java framework is the foundation of interview
  40. 【大厂面试】三面三问Spring循环依赖,请一定要把这篇看完(建议收藏)
  41. 一线互联网企业中,springboot入门项目
  42. 一篇文带你入门SSM框架Spring开发,帮你快速拿Offer
  43. 【面试资料】Java全集、微服务、大数据、数据结构与算法、机器学习知识最全总结,283页pdf
  44. 【leetcode刷题】24.数组中重复的数字——Java版
  45. 【leetcode刷题】23.对称二叉树——Java版
  46. 【leetcode刷题】22.二叉树的中序遍历——Java版
  47. 【leetcode刷题】21.三数之和——Java版
  48. 【leetcode刷题】20.最长回文子串——Java版
  49. 【leetcode刷题】19.回文链表——Java版
  50. 【leetcode刷题】18.反转链表——Java版
  51. 【leetcode刷题】17.相交链表——Java&python版
  52. 【leetcode刷题】16.环形链表——Java版
  53. 【leetcode刷题】15.汉明距离——Java版
  54. 【leetcode刷题】14.找到所有数组中消失的数字——Java版
  55. 【leetcode刷题】13.比特位计数——Java版
  56. oracle控制用户权限命令
  57. 三年Java开发,继阿里,鲁班二期Java架构师
  58. Oracle必须要启动的服务
  59. 万字长文!深入剖析HashMap,Java基础笔试题大全带答案
  60. 一问Kafka就心慌?我却凭着这份,图灵学院vip课程百度云