spring cloud中负载均衡Ribbon使用
spring cloud中负载均衡Ribbon使用
文章目录
- spring cloud中负载均衡Ribbon使用
- 一、简介
- 二、步骤
- 2.1 使用步骤
- 三、示例
- 3.1 注册中心
- 3.1.1 maven依赖
- 3.1.2 application.yaml配置
- 3.1.3 启动类
- 3.2 服务
- 3.2.1 maven依赖
- 3.2.2 application.yaml配置
- 3.2.3 服务相关类
- 3.3 客户端
- 3.3.1 maven依赖
- 3.3.2 application.yaml配置
- 3.3.3 客户相关类
- 3.4 测试
- 四、备注
- 4.1 常见问题
- 4.1.1 defaultZone书写非驼峰导致错误
- 4.1.2 服务名称有下划线导致错误
一、简介
spring cloud中，使用Ribbon作为负载均衡器，如果使用了feign，则自带负载均衡效果，开启即可。这里对Ribbon进行介绍。
二、步骤
2.1 使用步骤
开启负载均衡器步骤如下：
- 在创建RestTemplate的bean方法上添加负载均衡器注解@LoadBalanced
- 在服务调用时使用服务名(服务名不能有下划线，可为中划线)，不能使用ip地址，否则不生效
三、示例
这里使用注册中心spring_cloud_register_center、服务spring_cloud_provider(运行多个实例)、客户端spring_cloud_client_ribbon(使用负载均衡器)进行示例。
3.1 注册中心
注册中心为spring_cloud_register_center项目。
3.1.1 maven依赖
<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>4.0.0modelVersion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.3.2.RELEASEversion>
<relativePath/>
parent>
<groupId>com.dragon.studygroupId>
<artifactId>spring_cloud_register_centerartifactId>
<version>0.0.1-SNAPSHOTversion>
<name>spring_cloud_register_centername>
<description>Demo project for Spring Bootdescription>
<properties>
<java.version>1.8java.version>
<spring-cloud.version>Hoxton.SR6spring-cloud.version>
properties>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-serverartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-dependenciesartifactId>
<version>${spring-cloud.version}version>
<type>pomtype>
<scope>importscope>
dependency>
dependencies>
dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>
3.1.2 application.yaml配置
server:
port: 8010
spring:
application:
name: spring-cloud-register-center
eureka:
client:
serviceUrl:
defaultZone: http://localhost:${server.port}/eureka/
fetchRegistry: false #是否拉取注册信息，由于注册中心是单个结点，不需要拉取
registerWithEureka: false #是否注册自己，由于当前就是注册中心，帮不需要注册
3.1.3 启动类
package com.dragon.study.spring_cloud_register_center;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class SpringCloudRegisterCenterApplication {
public static void main(String[] args) {
SpringApplication.run(SpringCloudRegisterCenterApplication.class, args);
}
}
3.2 服务
服务为spring_cloud_provider项目。
3.2.1 maven依赖
<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>4.0.0modelVersion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.3.2.RELEASEversion>
<relativePath/>
parent>
<groupId>com.dragon.studygroupId>
<artifactId>spring_cloud_providerartifactId>
<version>0.0.1-SNAPSHOTversion>
<name>spring_cloud_providername>
<description>Demo project for Spring Bootdescription>
<properties>
<java.version>1.8java.version>
<spring-cloud.version>Hoxton.SR6spring-cloud.version>
properties>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>1.18.6version>
<scope>compilescope>
dependency>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-clientartifactId>
dependency>
dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-dependenciesartifactId>
<version>${spring-cloud.version}version>
<type>pomtype>
<scope>importscope>
dependency>
dependencies>
dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>
3.2.2 application.yaml配置
server:
port: 8011
spring:
application:
name: spring-cloud-provider
eureka:
instance:
prefer-ip-address: true #true表示使用ip注册，若为false，则表示使用系统hostname注册
client:
service-url:
default-zone: http://localhost:8010/eureka/
management:
endpoints:
web:
exposure:
include: "*"
3.2.3 服务相关类
定义实体bean类Stu.java
package com.dragon.study.spring_cloud_provider.bean;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Stu {
private String stuId;
private Integer age;
}
定义服务controller类StuController.java
package com.dragon.study.spring_cloud_provider.controller;
import com.dragon.study.spring_cloud_provider.bean.Stu;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@RestController
@RequestMapping("stu")
public class StuController {
@RequestMapping("getStu")
private Object getStu(Stu stu) {
System.out.println(stu);
return stu;
}
}
定义启动类SpringCloudProviderApplication.java
package com.dragon.study.spring_cloud_provider;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
@SpringBootApplication
@EnableDiscoveryClient
public class SpringCloudProviderApplication {
public static void main(String[] args) {
SpringApplication.run(SpringCloudProviderApplication.class, args);
}
}
启动，这里启动两个实例，只是端口号不一样，分别为8011和8021，在application.yaml中修改。
3.3 客户端
客户端为spring_cloud_client_ribbon项目。
3.3.1 maven依赖
<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0modelVersion>
<parent>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-parentartifactId>
<version>2.3.2.RELEASEversion>
<relativePath/>
parent>
<groupId>com.dragon.studygroupId>
<artifactId>spring_cloud_client_ribbonartifactId>
<version>0.0.1-SNAPSHOTversion>
<name>spring_cloud_client_ribbonname>
<description>Demo project for Spring Bootdescription>
<properties>
<java.version>1.8java.version>
<spring-cloud.version>Hoxton.SR6spring-cloud.version>
properties>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-clientartifactId>
dependency>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-ribbonartifactId>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>fastjsonartifactId>
<version>1.2.62version>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>fastjsonartifactId>
<version>1.2.4version>
<scope>compilescope>
dependency>
dependencies>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-dependenciesartifactId>
<version>${spring-cloud.version}version>
<type>pomtype>
<scope>importscope>
dependency>
dependencies>
dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
plugin>
plugins>
build>
project>
3.3.2 application.yaml配置
server:
port: 8051
spring:
application:
name: spring-cloud-ribbon-client
eureka:
instance:
preferIpAddress: true #true表示使用ip注册，若为false，则表示使用系统hostname注册
client:
serviceUrl:
defaultZone: http://localhost:8010/eureka/
3.3.3 客户相关类
定义实体bean
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@NoArgsConstructor
@AllArgsConstructor
public class Stu {
private String stuId;
private Integer age;
}
定义启动类
package com.dragon.study.spring_cloud_ribbon_client;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;
@SpringBootApplication
public class SpringCloudRibbonClientApplication {
@Bean
@LoadBalanced
public RestTemplate restTemplate(){
return new RestTemplate();
}
public static void main(String[] args) {
SpringApplication.run(SpringCloudRibbonClientApplication.class, args);
}
}
定义调用服务类
package com.dragon.study.spring_cloud_ribbon_client.controller;
import com.alibaba.fastjson.JSON;
import com.dragon.study.spring_cloud_ribbon_client.bean.Stu;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import javax.annotation.Resource;
import java.util.Map;
@RestController
@RequestMapping("stu")
public class StuController {
@Resource
private RestTemplate restTemplate;
@RequestMapping("getStu")
public Object getStu(Stu stu) {
Map<String, Object> m = JSON.parseObject(JSON.toJSONString(stu), Map.class);
return restTemplate.postForObject("http://spring-cloud-provider/stu/getStu?stuId={stuId}&age={age}", null, Stu.class, m);
}
}
3.4 测试
依次启动注册中心spring_cloud_register_center、服务spring_cloud_provider(运行多个实例)、客户端spring_cloud_client_ribbon。
测试：
#在客户端多次调用服务
GET http://localhost:8051/stu/getStu?stuId=001&age=17
Accept: application/json
可以发现在服务端多个实例有调用输出，说明负载均衡生效了。
四、备注
4.1 常见问题
4.1.1 defaultZone书写非驼峰导致错误
报错：
com.netflix.discovery.shared.transport.TransportException: Cannot execute request on any known server
解决:
将application.yaml中的default-zone书写改为驼峰形式defaultZone
4.1.2 服务名称有下划线导致错误
报错：
java.lang.IllegalStateException: Request URI does not contain a valid hostname:
解决：
ribbon实现负载均衡时，服务名称不能有下划线，可改为中划线