SpringCloud微服务之Ribbon负载均衡(一)
2020-03-17 16:07:50来源:博客园 阅读 ()
SpringCloud微服务之Ribbon负载均衡(一)
什么是微服务?什么是SpringCloud?
微服务是一种架构的模式,它提倡将一个应用程序划分成很多个微小的服务,服务与服务之间相互协调、相互配合。每个服务运行都是一个独立的进程,服务与服务之间采用轻量级的通讯机制相互沟通。简单的来说就是将一个庞大的复杂的单体应用进行划分成n多个微小的服务(一个服务负责一个业务),各个微服务都被独立的部署。
微服务与集群的区别是,微服务的每一个部署的服务都是不相同的,而集群部署的每一个服务都是相同的。
Spring Cloud是一个微服务框架,相比Dubbo等RPC框架,Spring Cloud提供的全套的分布式系统解决方案。它是在SpringBoot的基础上构建的。SpringCloud的五大神兽分别是Eureka、Ribbon、Feign、Hystrix、Zuul。
环境搭建
版本说明
springboot:2.0.3
springcloud:Finchley
创建一个父工程(maven项目)
选择maven,点击next
然后点击完成
修改父工程pom.xml
<?xml version="1.0" encoding="UTF-8"?> <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.lzh</groupId> <artifactId>my-springcloud-01</artifactId> <packaging>pom</packaging> <version>1.0-SNAPSHOT</version> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> <junit.version>4.12</junit.version> <log4j.version>1.2.17</log4j.version> <lombok.version>1.16.18</lombok.version> </properties> <dependencyManagement> <dependencies> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-dependencies</artifactId> <version>Finchley.RELEASE</version> <!--<version>Dalston.SR1</version>--> <type>pom</type> <scope>import</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-dependencies</artifactId> <version>2.0.3.RELEASE</version> <type>pom</type> <scope>import</scope> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.0.4</version> </dependency> <dependency> <groupId>com.alibaba</groupId> <artifactId>druid</artifactId> <version>1.0.31</version> </dependency> <dependency> <groupId>org.mybatis.spring.boot</groupId> <artifactId>mybatis-spring-boot-starter</artifactId> <version>1.3.0</version> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-core</artifactId> <version>1.2.3</version> </dependency> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>${junit.version}</version> <scope>test</scope> </dependency> <dependency> <groupId>log4j</groupId> <artifactId>log4j</artifactId> <version>${log4j.version}</version> </dependency> </dependencies> </dependencyManagement> <build> <finalName>microservicecloud</finalName> <resources> <resource> <directory>src/main/resources</directory> <filtering>true</filtering> </resource> </resources> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-resources-plugin</artifactId> <configuration> <delimiters> <delimit>$</delimit> </delimiters> </configuration> </plugin> </plugins> </build> </project>
创建子工程(maven项目)
工程名称:microservice-consumer-80
pom.xml文件
<?xml version="1.0" encoding="UTF-8"?> <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"> <parent> <artifactId>my-springcloud-01</artifactId> <groupId>com.lzh</groupId> <version>1.0-SNAPSHOT</version> </parent> <modelVersion>4.0.0</modelVersion> <artifactId>microservice-consumer-80</artifactId> <dependencies> <dependency> <groupId>com.lzh</groupId> <artifactId>microservice-api</artifactId> <version>1.0-SNAPSHOT</version> </dependency> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId> </dependency> <!-- 整合ribbon --> <dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-netflix-ribbon</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-actuator</artifactId> </dependency> </dependencies> </project>
编码实现
在主启动类上加上@EnableDiscoveryClient注解
创建一个配置文件ConfigBean.java,new一个RestTemplate远程调用模板,加入@LoadBalanced注解,开启负载均衡
import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import org.springframework.web.client.RestTemplate; /** * @author lzh * create 2019-11-05-9:58 */ @Configuration public class ConfigBean { @Bean //加入负载均衡 //Spring Cloud Ribbon是基于Netflix Ribbon实现的一套客户端 负载均衡的工具 @LoadBalanced public RestTemplate getRestTemplate(){ return new RestTemplate(); } }
在服务层DeptServiceImpl.java类中用RestTemplate模板工具调用,这里使用服务名称调用,如果服务名称相同,则会进行顺序轮询调用
import com.lzh.cloud.model.Dept; import com.lzh.cloud.service.DeptService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.web.client.RestTemplate; import java.util.List; /** * @author lzh * create 2019-11-05-10:27 */ @Service public class DeptServiceImpl implements DeptService { /** * 使用restTemplate访问restful接口非常的简单粗暴无脑。 * (url, requestMap, ResponseBean.class)这三个参数分别代表 * REST请求地址、请求参数、HTTP响应转换被转换成的对象类型。 */ @Autowired private RestTemplate restTemplate; //private static final String REST_URL_PREFIX = "http://localhost:8001"; private static final String REST_URL_PREFIX = "http://MICROSERVICECLOUD-DEPT"; @Override public boolean add(Dept dept) { return restTemplate.postForObject(REST_URL_PREFIX + "/dept/add", dept, Boolean.class); } @Override public Dept get(Long id) { return restTemplate.getForObject(REST_URL_PREFIX + "/dept/get/" + id, Dept.class); } @Override public List<Dept> list() { return restTemplate.getForObject(REST_URL_PREFIX + "/dept/list/", List.class); } @Override public Object discovery() { return restTemplate.getForObject(REST_URL_PREFIX + "/dept/discovery", Object.class); } }
自定义轮询规则
在主启动类的前一个包创建一个配置MySelRule类,注意不要跟主启动类同包或者在主启动类的子包中创建
import com.netflix.loadbalancer.IRule; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; /** * @author lzh * create 2019-05-19-17:10 */ @Configuration public class MySelfRule { @Bean public IRule myRule(){ //return new RandomRule(); //Ribbon默认是轮询,我自定义为随机 //return new RoundRobinRule(); //Ribbon默认是轮询,我自定义为随机 return new RandomRule_LZH(); // 我自定义为每台机器5次 } }
参照源码,自定义轮询算法RandomRule_LZH.java
import com.netflix.client.config.IClientConfig; import com.netflix.loadbalancer.AbstractLoadBalancerRule; import com.netflix.loadbalancer.ILoadBalancer; import com.netflix.loadbalancer.Server; import java.util.List; public class RandomRule_LZH extends AbstractLoadBalancerRule { // total = 0 // 当total==5以后,我们指针才能往下走, // index = 0 // 当前对外提供服务的服务器地址, // total需要重新置为零,但是已经达到过一个5次,我们的index = 1 // 分析:我们5次,但是微服务只有8001 8002 8003 三台,OK? // private int total = 0; // 总共被调用的次数,目前要求每台被调用5次 private int currentIndex = 0; // 当前提供服务的机器号 public Server choose(ILoadBalancer lb, Object key) { if (lb == null) { return null; } Server server = null; while (server == null) { if (Thread.interrupted()) { return null; } List<Server> upList = lb.getReachableServers(); List<Server> allList = lb.getAllServers(); int serverCount = allList.size(); if (serverCount == 0) { /* * No servers. End regardless of pass, because subsequent passes only get more * restrictive. */ return null; } // int index = rand.nextInt(serverCount);// java.util.Random().nextInt(3); // server = upList.get(index); // private int total = 0; // 总共被调用的次数,目前要求每台被调用5次 // private int currentIndex = 0; // 当前提供服务的机器号 if (total < 5) { server = upList.get(currentIndex); total++; } else { total = 0; currentIndex++; if (currentIndex >= upList.size()) { currentIndex = 0; } } if (server == null) { /* * The only time this should happen is if the server list were somehow trimmed. * This is a transient condition. Retry after yielding. */ Thread.yield(); continue; } if (server.isAlive()) { return (server); } // Shouldn't actually happen.. but must be transient or a bug. server = null; Thread.yield(); } return server; } @Override public Server choose(Object key) { return choose(getLoadBalancer(), key); } @Override public void initWithNiwsConfig(IClientConfig clientConfig) { // TODO Auto-generated method stub } }
最后不要忘了在主启动类加上注解,使用自定义轮询算法configuration = MySelfRule.class
import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.netflix.eureka.EnableEurekaClient; /** * @author lzh * create 2019-11-04-22:26 */ @SpringBootApplication @EnableEurekaClient //自定义负载均衡规则 //在启动该为服务的时候就能去加载我们的自定义Ribbon配置类,从而使配置生效 //configuration = MySelfRule.class 把MySelfRule配置类加载进容器 @RibbonClient(name = "MICROSERVICECLOUD-DEPT",configuration = MySelfRule.class) @EnableDiscoveryClient public class MyConsumerApplication_80 { public static void main(String[] args) { SpringApplication.run(MyConsumerApplication_80.class); } }
代码
github:https://github.com/LZHDonald/my-springcloud-01/tree/master/microservice-consumer-80
原文链接:https://www.cnblogs.com/lzhdonald/p/11798912.html
如有疑问请与原作者联系
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