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服务器之家 - 编程语言 - JAVA教程 - SpringCloud之Feign示例详解

SpringCloud之Feign示例详解

2021-03-19 13:15Bob_F JAVA教程

本篇文章主要介绍了SpringCloud之Feign示例详解,详细的介绍了Feign简介和使用,小编觉得挺不错的,现在分享给大家,也给大家做个参考。一起跟随小编过来看看吧

Feign简介

Feign 是一个声明web服务客户端,这便得编写web服务客户端更容易,使用Feign 创建一个接口并对它进行注解,它具有可插拔的注解支持包括Feign注解与JAX-RS注解,Feign还支持可插拔的编码器与解码器,Spring Cloud 增加了对 Spring MVC的注解,Spring Web 默认使用了HttpMessageConverters, Spring Cloud 集成 Ribbon 和 Eureka 提供的负载均衡的HTTP客户端 Feign.

声明式REST客户端:Feign

先要启动eureka_register_service工程(注册中心)和biz-service-0工程(服务生产者)

创建一个maven工程eureka_feign_client

pom.xml

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<parent>
 
<groupId>org.springframework.boot</groupId>
 
<artifactId>spring-boot-starter-parent</artifactId>
 
<version>1.4.3.RELEASE</version>
 
<relativePath/> <!-- lookup parent from repository -->
 
</parent>
 
<properties>
 
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
 
<java.version>1.8</java.version>
 
</properties>
 
<dependencies>
 
  <dependency>
 
    <groupId>org.springframework.cloud</groupId>
 
    <artifactId>spring-cloud-starter-feign</artifactId>
 
  </dependency>
 
  <dependency>
 
    <groupId>org.springframework.cloud</groupId>
 
    <artifactId>spring-cloud-starter-eureka</artifactId>
 
  </dependency>
 
  <dependency>
 
    <groupId>org.springframework.boot</groupId>
 
    <artifactId>spring-boot-starter-web</artifactId>
 
  </dependency>
 
  <dependency>
 
    <groupId>org.springframework.boot</groupId>
 
    <artifactId>spring-boot-starter-test</artifactId>
 
    <scope>test</scope>
 
  </dependency>
 
</dependencies>
 
<dependencyManagement>
 
  <dependencies>
 
    <dependency>
 
  <groupId>org.springframework.cloud</groupId>
 
  <artifactId>spring-cloud-dependencies</artifactId>
 
  <version>Brixton.SR5</version>
 
  <type>pom</type>
 
  <scope>import</scope>
 
</dependency>
 
  </dependencies>
 
</dependencyManagement>

在应用主类中通过@EnableFeignClients注解开启Feign功能

启动文件FeignApplication.java

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

定义服务接口类UserClient.java

使用@FeignClient("biz-service-0")注解来绑定该接口对应biz-service-0服务

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@FeignClient("biz-service-0")
 
public interface UserClient {
 
  @RequestMapping(method = RequestMethod.GET, value = "/getuser")
 
  public User getuserinfo();  
 
  @RequestMapping(method = RequestMethod.GET, value = "/getuser")
 
  public String getuserinfostr();  
 
  @RequestMapping(method = RequestMethod.GET, value = "/info")
 
  public String info();
}

在web层中调用上面定义的UserController,具体如下

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@RestController
 
public class UserController {
 
  @Autowired
 
  UserClient userClient;
 
  @RequestMapping(value = "/getuserinfo", method = RequestMethod.GET)
 
  public User getuserinfo() {
 
    return userClient.getuserinfo();
 
  }
 
  @RequestMapping(value = "/getuserinfostr", method = RequestMethod.GET)
 
  public String getuserinfostr() {
 
    return userClient.getuserinfostr();
  }
 
  @RequestMapping(value = "/info", method = RequestMethod.GET)
 
  public String info() {
 
    return userClient.info();
 
  }
}

application.properties配置变量

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spring.application.name=feign-consumer
 
server.port=8004
 
eureka.client.serviceUrl.defaultZone=http://localhost:8000/eureka/

访问 http://127.0.0.1:8004/getuserinfo

总结:

其实通过Feign封装了HTTP调用服务方法,使得客户端像调用本地方法那样直接调用方法,类似Dubbo中暴露远程服务的方式,区别在于Dubbo是基于私有二进制协议,而Feign本质上还是个HTTP客户端

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。

原文链接:http://www.cnblogs.com/xiaojunbo/p/7094377.html

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