Spring Cloud之Feign客户端调用工具

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>
	<!-- 管理依赖 -->
	<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>
		<!-- SpringBoot整合Web组件 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<!-- SpringBoot整合eureka客户端 -->
		<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>
	<!-- 注意： 这里必须要添加， 否者各种依赖有问题 -->
	<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>
	<!-- 管理依赖 -->
	<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>
		<!-- SpringBoot整合Web组件 -->
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<!-- SpringBoot整合eureka客户端 -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
		</dependency>
	</dependencies>
	<!-- 注意： 这里必须要添加， 否者各种依赖有问题 -->
	<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>
	<!-- 管理依赖 -->
	<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>
		<!--SpringCloud eureka-server -->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
		</dependency>
	</dependencies> 
	<!-- 注意： 这里必须要添加， 否者各种依赖有问题 -->
	<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);
    }
    
}