Spring Cloud(3)——服务消费者

一、简介

Feign是一个声明式的Web Service客户端,它使得编写Web Serivce客户端变得更加简单。我们只需要使用Feign来创建一个接口并用注解来配置它既可完成。它具备可插拔的注解支持,包括Feign注解和JAX-RS注解。Feign也支持可插拔的编码器和解码器。Spring Cloud为Feign增加了对Spring MVC注解的支持,还整合了Ribbon和Eureka来提供均衡负载的HTTP客户端实现。

二、项目实例

创建maven工程microservice-consumer-user

1、在pom.xml中添加依赖

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 <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/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.baibei.comsumer</groupId>
<artifactId>microservice-consumer-user</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>microservice-consumer-user Maven Webapp</name>
<url>http://maven.apache.org</url>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.4.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<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>Camden.SR5</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<build>
<finalName>microservice-consumer-user</finalName>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>

2、创建UserConsumerApplication.java

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package com.baibei.consumer.user;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

/**
* @author: 会跳舞的机器人
* @email:2268549298@qq.com
* @date: 17/2/17 上午11:45
* @description:用户服务消费者
*/
@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class UserConsumerApplication {

public static void main(String[] args) {
SpringApplication.run(UserConsumerApplication.class, args);
}
}
  • EnableDiscoveryClient注解用来标识开启服务发现功能
  • EnableFeignClients注解用来开启Feign功能

3、创建application.properties文件

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spring.application.name=microservice-consumer-user
server.port=8005

# 注册中心地址
eureka.client.serviceUrl.defaultZone=http://eureka-server-peer1:8761/eureka/,http://eureka-server-peer2:8762/eureka/,http://eureka-server-peer3:8763/eureka/

# Indicates whether this client should fetch eureka registry information from eureka server
# 客户端是否要从eureka server获取注册信息,默认为true
eureka.client.fetchRegistry=true

# Indicates how often(in seconds) to fetch the registry information from the eureka server
# 从eureka server获取注册信息的频率,默认为30秒,缩短配置时间可以缓解服务上线时间过长的问题
eureka.client.registryFetchIntervalSeconds=10


# 自定义负载均衡策略,microservice-provider-user为服务应用名
microservice-provider-user.ribbon.NFLoadBalancerRuleClassName=com.netflix.loadbalancer.RandomRule

4、创建UserFeignClient

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package com.baibei.consumer.user.service;

import com.baibei.common.core.api.ApiResult;
import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.*;

/**
* @author: 会跳舞的机器人
* @date: 2017/3/29 16:54
* @description: 用户服务调用端
*/
@FeignClient(name = "microservice-provider-user")
public interface UserFeignClient {

/**
* 根据ID查找用户
*
* @param
* @return
*/
@RequestMapping(value = "/user/{id}",method = RequestMethod.GET)
ApiResult findUserById(@PathVariable("id") Integer id);


}
  • FeignClient注解用来绑定对应的服务

5、web层的调用

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package com.baibei.consumer.user.controller;

import com.baibei.common.core.api.ApiResult;
import com.baibei.consumer.user.service.UserFeignClient;
import org.apache.log4j.Logger;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
* @author: 会跳舞的机器人
* @email:2268549298@qq.com
* @date: 17/2/17 上午11:51
* @description:
*/
@RestController
@RequestMapping("/user")
public class UserController {
private Logger logger = Logger.getLogger(UserController.class);

@Autowired
private UserFeignClient userFeignClient;


/**
* 根据ID查找用户信息
*
* @param id
* @return
*/
@GetMapping("/{id}")
public ApiResult getUser(@PathVariable Integer id) {

return userFeignClient.findUserById(id);
}
}

通过注入UserFeignClient即可实现像调用本地方法一样去调用远程服务方法

附录:项目目录截图

image

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