微服务之SpringCloud-聚合项目及Feign声明式服务调用以及调用时应注意的问题

本文链接：https://blog.youkuaiyun.com/Websphere_zxf/article/details/91044525

本文详细介绍Feign作为声明式HTTP客户端在微服务架构中的应用，通过实例展示如何简化WebService调用，包括项目结构、依赖配置及接口实现。

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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。它的目的就是让Web Service调用更加简单。

下面就用一个简单的微服务项目说明

项目结构：聚合项目，子父工程

项目获取地址：https://github.com/XiaoFengSophia/springcloud2.0-lancoo-parents

该案例中的member服务和order服务都是注册在Eureka注册中心集群中，关于Eureka注册中心集群的使用请点击springboot+springcloud+eureka实现高可用注册中心了解详情！

父工程pom.xml

<!-- SpringCloud 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.boot</groupId>
			<artifactId>spring-boot-starter</artifactId>
		</dependency>
		<!-- SpringBoot整合feign客户端 -->
		<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>

springcloud2.0-lancoo-api-member-service 接口

pom.xml(MemberService接口)

<dependencies>
  	<!-- 引入公共项目  -->
  	<dependency>
  		<groupId>lancoo</groupId>
  		<artifactId>springccloud2.0-lancoo-common</artifactId>
  		<version>0.0.1-SNAPSHOT</version>
  	</dependency>
  </dependencies>

IMemberService

public interface IMemberService {
	
	@RequestMapping("/getMember")
	public UserEntity getMember(@RequestParam("name") String name);//这里必须加@RequestParam("name")，否则远程调用时参数为null
	
	@RequestMapping("/getUserInfo")
	public ResponseBase getUserInfo();

}

UserEntity

public class UserEntity {
	
	private String name;
	private Integer age;
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getAge() {
		return age;
	}
	public void setAge(Integer age) {
		this.age = age;
	}
	public UserEntity(String name, Integer age) {
		super();
		this.name = name;
		this.age = age;
	}
	public UserEntity() {
		super();
		// TODO Auto-generated constructor stub
	}
	@Override
	public String toString() {
		return "UserEntity [name=" + name + ", age=" + age + "]";
	}

springcloud2.0-lancoo-api-member-service-impl 实现类

pom.xml

<!-- 引入member接口项目 -->
  	<dependency>
	  	<groupId>lancoo</groupId>
	    <artifactId>springcloud2.0-lancoo-api-member-service</artifactId>
	    <version>0.0.1-SNAPSHOT</version>
  	</dependency>

application.yml

#启动服务端口
server: 
  port: 8001
#服务名称(服务注册到Eureka注册中心)
spring:
  application:
    name: zxf-lancoo-member
#服务注册到Eureka地址
eureka:
  client:
    service-url:
      defaultZone: http://127.0.0.1:8100/eureka,http://127.0.0.1:8200/eureka
     
#因为是注册中心，不会自己注册
    register-with-eureka: true
#是否需要从eureka上获取注册信息
    fetch-registry: true

MemberServiceImpl

@RestController
public class MemberServiceImpl extends BaseApiService implements IMemberService {
	@Autowired
	private LoadBalancerClient loadBalancerClient;
	
	@RequestMapping("/getMember")
	public UserEntity getMember(@RequestParam("name")String name) {//这里必须加@RequestParam("name")，否则远程调用时参数为null
		// TODO Auto-generated method stub
		UserEntity userEntity = new UserEntity();
		userEntity.setName(name);
		userEntity.setAge(20);
		return userEntity;
	}


}

AppMember 启动类

@SpringBootApplication
@EnableEurekaClient   //开启Eureka客户端
@EnableFeignClients   //开启Feign客户端
public class AppMember {
	
	public static void main(String[] args) {
		SpringApplication.run(AppMember.class, args);
	}

}

springcloud2.0-lancoo-api-order-service 接口

pom.xml(OrderService)

<!-- 引入公共项目  -->
  	<dependency>
		<groupId>lancoo</groupId>
	    <artifactId>springccloud2.0-lancoo-common</artifactId>
	    <version>0.0.1-SNAPSHOT</version>
  	</dependency>

IOrderService

public interface IOrderService {
	
	//订单服务调用会员服务接口信息 feign
	@RequestMapping("/orderToMember")
	public String orderToMember(String name);
	
	//订单服务调用会员服务接口
	@RequestMapping("/orderToMemberUserInfo")
	public ResponseBase orderToMemberUserInfo();
	
	//订单服务调用会员服务接口
	@RequestMapping("/orderInfo")
	public ResponseBase orderInfo();
	

}

springcloud2.0-lancoo-api-order-service-impl OrderService实现类

pom.xml

<!-- order接口项目 -->
  	<dependency>
  		 <groupId>lancoo</groupId>
	     <artifactId>springcloud2.0-lancoo-api-order-service</artifactId>
	     <version>0.0.1-SNAPSHOT</version>
  	</dependency>
  	<!-- 引入member接口项目 -->
  	<dependency>
  		 <groupId>lancoo</groupId>
	     <artifactId>springcloud2.0-lancoo-api-member-service</artifactId>
	     <version>0.0.1-SNAPSHOT</version>
  	</dependency>

application.yml

#启动服务端口
server: 
  port: 8021
#服务名称(服务注册到Eureka注册中心)
spring:
  application:
    name: zxf-lancoo-order
#服务注册到Eureka地址
eureka:
  client:
    service-url:
      defaultZone: http://localhost:8100/eureka
     
#因为是注册中心，不会自己注册
    register-with-eureka: true
#是否需要从eureka上获取注册信息
    fetch-registry: true
    
###设置feign客户端超时时间
#springcloud feign默认开启支持ribbon
ribbon:
###指的是建立连接所用的时间，适用于网络状况正常的情况下，两端连接所用的时间。
 ReadTimeout: 5000
###指的是建立连接后从服务器读取到可用资源所用的时间。 
 ConnectTimeout: 5000

OrderServiceImpl

@RestController
public class OrderServiceImpl extends BaseApiService implements IOrderService {
	
	
	//订单服务继承会员服务接口，用来实现feign客户端的调用，减少重复代码接口
	@Autowired
	private IMemberServiceFeign iMemberServiceFeign;

	@RequestMapping("/orderToMember")
	public String orderToMember(String name) {
		// TODO Auto-generated method stub
		UserEntity userEntity = iMemberServiceFeign.getMember(name);
		return userEntity==null?"未找到任何信息":userEntity.toString();
	}
	

}

IMemberServiceFeign

/**
 * 继承的作用解决代码重复
 * 订单服务继承会员服务接口，实现feign客户端的调用
 * @author lancoo
 *
 */
@FeignClient("zxf-lancoo-member")
public interface IMemberServiceFeign extends IMemberService {
	
	

}

AppOrder

@SpringBootApplication
@EnableEurekaClient  //Eureka客户端
@EnableFeignClients  //Feign客户端
public class AppOrder {
	
	public static void main(String[] args) {
		SpringApplication.run(AppOrder.class, args);
	}

}

公共子模块

BaseApiService

@Component
public class BaseApiService {
	
	public ResponseBase setResultError(Integer code,String msg) {
		
		return setResult(code, msg,null);
	}
	//返回错误，可以传msg
	public ResponseBase setResultError(String msg) {
		
		return setResult(500,msg,null);
	}
	//返回成功，可以传data值
	public ResponseBase setResultSuccess(Object data) {
		
		return setResult(200,"处理成功",data);
	}
	//返回成功，没有data值
	public ResponseBase setResultSuccess() {
		
		return setResult(200,"处理成功",null);
	}
	//返回成功，没有data值
	public ResponseBase setResultSuccess(String msg) {
		
		return setResult(200,msg,null);
	}
	//通用封装
	public ResponseBase setResult(Integer code,String msg,Object data) {
		
		return new ResponseBase(code,msg,data);
	}

}

ResponseBase

@Slf4j
public class ResponseBase {
	
	private Integer rtnCode;
	private String msg;
	private Object data;
	public ResponseBase() {
		super();
		// TODO Auto-generated constructor stub
	}
	public ResponseBase(Integer rtnCode, String msg, Object data) {
		super();
		this.rtnCode = rtnCode;
		this.msg = msg;
		this.data = data;
	}
	public Integer getRtnCode() {
		return rtnCode;
	}
	public void setRtnCode(Integer rtnCode) {
		this.rtnCode = rtnCode;
	}
	public String getMsg() {
		return msg;
	}
	public void setMsg(String msg) {
		this.msg = msg;
	}
	public Object getData() {
		return data;
	}
	public void setData(Object data) {
		this.data = data;
	}
	@Override
	public String toString() {
		return "ResponseBase [rtnCode=" + rtnCode + ", msg=" + msg + ", data=" + data + "]";
	}
	
	
	
}

访问member服务：http://127.0.0.1:8001/getMember?name=张三