Spring Cloud之Feign客户端调用工具

逃离我推掉我的手 2022-01-28 13:41 241阅读 0赞

# [Spring Cloud之Feign客户端调用工具][Spring Cloud_Feign] #

# feign介绍 #

Feign客户端是一个web声明式http远程调用工具，提供了接口和注解方式进行调用。

Spring Cloud 支持 RestTemplate  Fetin

Feign客户端实际开发中用的最多 ，易读性比较强。

主要调用部分：

pom：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.toov5</groupId>
      <artifactId>order</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      
      <parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.0.1.RELEASE</version>
    	</parent>
    	
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Finchley.M7</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    	<dependencies>
    		
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    		</dependency>
           <dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-openfeign</artifactId>
    		</dependency>
           
    	</dependencies>
    	
    	<repositories>
    		<repository>
    			<id>spring-milestones</id>
    			<name>Spring Milestones</name>
    			<url>https://repo.spring.io/libs-milestone</url>
    			<snapshots>
    				<enabled>false</enabled>
    			</snapshots>
    		</repository>
    	</repositories>
    </project>

yml：

###服务启动端口号
    server:
      port: 8002
    ###服务名称(服务注册到eureka名称)  
    spring:
        application:
            name: app-toov5-order
    ###服务注册到eureka地址
    eureka:
      client:
        service-url:
               defaultZone: http://127.0.0.1:8100/eureka
    
               
    ###因为该应用为注册中心，不会注册自己
        register-with-eureka: true
    ###是否需要从eureka上获取注册信息
        fetch-registry: true

Feign

package com.toov5.Feign;
    
    import org.springframework.cloud.openfeign.FeignClient;
    import org.springframework.web.bind.annotation.RequestMapping;
    
    @FeignClient(name="app-toov5-member")   //name就是服务名称
    public interface MemberFeign {
       //Feign书写方式 以Spring mvc接口形式书写
        
        @RequestMapping("/getMember")   //接口形式  实现是交给Member实现的
        public String getMember();  //底层自动转换成http协议实现rpc远程调用
        
    }

controller

package com.toov5.api.controller;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import com.toov5.Feign.MemberFeign;
    
    @RestController
    public class FeignController {
         @Autowired
         private MemberFeign memberFeign;
        
         @RequestMapping("/getFeignMember")
         public String feignMember() {
            return memberFeign.getMember();
         }
    }

启动类：

package com.toov5;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    import org.springframework.cloud.openfeign.EnableFeignClients;
    
    @SpringBootApplication(scanBasePackages={"com.toov5.*"})
    @EnableEurekaClient
    @EnableFeignClients   //可以开启feign客户端权限   
    public class AppOrder {
      public static void main(String[] args) {
        SpringApplication.run(AppOrder.class, args);
    }
      //解决RestTemplate找不到问题  把restTemplate注册到Spring Boot容器中
    //  @Bean
    //  @LoadBalanced   手写的 不要去实现本地负载均衡效果了
    //  RestTemplate restTemplate() {  
    //      return new RestTemplate();
    //  }
    //  
    }

Member(不用变) 服务提供者不变

pom：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.toov5</groupId>
      <artifactId>member</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      
      
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.0.1.RELEASE</version>
    	</parent>
    	
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Finchley.M7</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    	<dependencies>
    		
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    		</dependency>
    	</dependencies>
    	
    	<repositories>
    		<repository>
    			<id>spring-milestones</id>
    			<name>Spring Milestones</name>
    			<url>https://repo.spring.io/libs-milestone</url>
    			<snapshots>
    				<enabled>false</enabled>
    			</snapshots>
    		</repository>
    	</repositories>
      
    </project>

yml：

###服务启动端口号
    server:
      port: 8009
    ###服务名称(服务注册到eureka名称)  
    spring:
        application:
            name: app-toov5-member
    ###服务注册到eureka地址
    eureka:
      client:
        service-url:
        ##当前会员注册到eureka服务  地址+端口号 
               defaultZone: http://127.0.0.1:8100/eureka
               
    ###因为该应用为注册中心，不会注册自己
        register-with-eureka: true
    ###是否需要从eureka上获取注册信息
        fetch-registry: true

controller

package com.toov5.api.controller;
    
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @RestController
    public class MemberApiController {
        @Value("${server.port}")
        private String serverPort;
        
        @RequestMapping("/getMember")
      public String getMember() {
            return "会员服务"+serverPort;
      }
    }

启动类

package com.toov5.api;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
    
    @SpringBootApplication
    @EnableEurekaClient   //注册到eureka
    public class AppMember {
       
        public static void main(String[] args) {
            SpringApplication.run(AppMember.class, args);
        }
        
    }

Eureka

pom:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
      <modelVersion>4.0.0</modelVersion>
      <groupId>com.toov5</groupId>
      <artifactId>SpringCloud-eureka-server</artifactId>
      <version>0.0.1-SNAPSHOT</version>
      <parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.0.1.RELEASE</version>
    	</parent>
    	
    	<dependencyManagement>
    		<dependencies>
    			<dependency>
    				<groupId>org.springframework.cloud</groupId>
    				<artifactId>spring-cloud-dependencies</artifactId>
    				<version>Finchley.M7</version>
    				<type>pom</type>
    				<scope>import</scope>
    			</dependency>
    		</dependencies>
    	</dependencyManagement>
    	<dependencies>
    		
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
    		</dependency>
    	</dependencies> 
    	
    	<repositories>
    		<repository>
    			<id>spring-milestones</id>
    			<name>Spring Milestones</name>
    			<url>https://repo.spring.io/libs-milestone</url>
    			<snapshots>
    				<enabled>false</enabled>
    			</snapshots>
    		</repository>
    	</repositories>
      
    </project>

yml:

###eureka 服务端口号
    server:
      port: 8100
    ###服务注册名称
    eureka:
      instance:
      ##注册中心ip地址
        hostname: 127.0.0.1
    ###客户端调用地址
      client:
        serviceUrl:
          defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
    ###因为该应用为注册中心，不会注册自己 （集群设为true）
        register-with-eureka: false
    ###因为自己为注册中心 ,不会去在该应用中的检测服务 
        fetch-registry: false

启动：

package com.toov5;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
    
    @EnableEurekaServer   //开启注册中心
    @SpringBootApplication 
    public class AppEureka {
      
         public static void main(String[] args) {
               SpringApplication.run(AppEureka.class, args);
        }
        
    }

![1179709-20181113232552549-312907456.png][]

[Spring Cloud_Feign]: https://www.cnblogs.com/toov5/p/9955561.html
[1179709-20181113232552549-312907456.png]: /images/20220128/0298d2dce83140949cf6a19af193727b.png