SpringCloud使用Feign实现动态路由操作_Java教程

一、理解及原理

1.1理解

Feign
基于接口 + 注解的方式，一个http请求调用的轻量级框架

Feign是Netflix开发的声明式、模板化的HTTP客户端， Feign可以帮助我们更快捷、优雅地调用HTTP API。

Feign是一种声明式、模板化的HTTP客户端(仅在Application Client中使用)。声明式调用是指，就像调用本地方法一样调用远程方法，无需感知操作远程http请求

SpringCloud使用Feign实现动态路由操作

1.2原理

SpringCloud使用Feign实现动态路由操作

二、Feign搭建实现步骤

创建Springboot基础项目
在注册中心（Eureka）配置的基础上，进行配置Feign

三、配置文件（pom.xml）

基础配置：

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

整体：

<dependencies>
<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>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
<version>RELEASE</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
</dependency>
<dependency>
<groupId>org.freemarker</groupId>
<artifactId>freemarker</artifactId>
<version>2.3.30</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<scope>runtime</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
<scope>runtime</scope>
</dependency>
<!-- Swagger -->
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger-ui</artifactId>
<version>2.4.0</version>
</dependency>
<dependency>
<groupId>io.springfox</groupId>
<artifactId>springfox-swagger2</artifactId>
<version>2.4.0</version>
</dependency>
<dependency>
<groupId>com.github.xiaoymin</groupId>
<artifactId>swagger-bootstrap-ui</artifactId>
<version>1.8.7</version>
</dependency>
<!--添加lombok-->
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<version>RELEASE</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>20.0</version>
</dependency>
<dependency>
<groupId>com.google.guava</groupId>
<artifactId>guava</artifactId>
<version>19.0</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.mybatis.spring.boot</groupId>
<artifactId>mybatis-spring-boot-starter</artifactId>
<version>1.3.2</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<!--pagehelper分页-->
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper-spring-boot-starter</artifactId>
<version>1.2.11</version>
</dependency>
<dependency>
<groupId>commons-codec</groupId>
<artifactId>commons-codec</artifactId>
<version>1.11</version>
</dependency>
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.6</version>
</dependency>
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>2.8.6</version>
</dependency>

<!--验证码https://blog.csdn.net/qq_41853447/article/details/105893567-->
<dependency>
<groupId>com.github.whvcse</groupId>
<artifactId>easy-captcha</artifactId>
<version>1.6.2</version>
</dependency>
<!--security权限管理-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>

</dependencies>

三、程序代码

在启动类上加上@EnableFeignClients，开启Feign的应用

@EnableEurekaServer
@EnableSwagger2
@SpringBootApplication
@EnableFeignClients(basePackages = "com.personal.pserver")
public class PserverApplication {

public static void main(String[] args) {
SpringApplication.run(PserverApplication.class, args);
System.out.println("========================person-server已启动========================");
}

}

启动类添加完成之后，在指定需要访问的service注册使用，

见其他博主讲解：

在通过Feign来实现远程服务调用时，需要提供一个本地接口来继承服务标准工程提供的服务接口。这个本地接口不需要给予任何实现，在底层Spring容器会为这个接口提供一个基于JDK实现的代理对象，这个代理对象由Feign技术提供具体的HandlerInterceptor逻辑，实现远程的调用。实现过程类似通过代码调用LoadBalancerClient实现的Rest远程访问。
　　而本地接口继承服务标准接口后，需要提供注解@FeignClient，注解的属性name代表当前接口要调用的远程服务的应用命名。

SpringCloud使用Feign实现动态路由操作

@RestController
@Api(tags = "平台基本信息管理")
@RequestMapping("/v1/pserver/platform/manager")
public class PlatformController {

@Autowired
private PPlatformService platformService;

@ApiOperation(value = "获取平台基本信息", notes = "获取平台基本信息", httpMethod = "GET")
@RequestMapping(value = "/findPlatformInfo",method = RequestMethod.GET)
public PPlatform findPlatformInfo(@RequestParam("platformId") String platformId) {
PPlatform pPlatform = platformService.findOnePlatformById(platformId);
return pPlatform;
}
}

@FeignClient(name="p-platform-service")
public interface PPlatformService {

/***
* 获取平台基本信息
* @param platformId
* @return
*/
@RequestMapping(value="/findPlatformInfo",method = RequestMethod.GET)
PPlatform findOnePlatformById(@RequestParam(value="platformId") String platformId);

}