一、Client代码示例
说明：此处使用的SpringBoot版本为2.1.13.RELEASE，SpringCloud版本为Greenwich.SR5
为了演示负载均衡就需要有多个client，此处我们只需要将之前的client复制一份，稍作修改即可
1、maven依赖
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<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-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
2、application.yml
client
server:
port: 8001
spring:
application:
name: client
eureka:
instance:
hostname: localhost
prefer-ip-address: true
instance-id: client-8001
client:
service-url:
defaultZone: http://eureka7001:7001/eureka/,http://eureka7002:7002/eureka/,http://eureka7003:7003/eureka/
#info信息
info:
app:
name: client-8001
company:
name: www.xxx.com
build:
artifactId: ${project.artifactId}
version: ${project.version}
client2
server:
port: 8002
spring:
application:
name: client
eureka:
instance:
hostname: localhost
prefer-ip-address: true
instance-id: client-8002
client:
service-url:
defaultZone: http://eureka7001:7001/eureka/,http://eureka7002:7002/eureka/,http://eureka7003:7003/eureka/
#info信息
info:
app:
name: client-8002
company:
name: www.xxx.com
build:
artifactId: ${project.artifactId}
version: ${project.version}
3、启动类
启动类是一样的，此处代码就只贴了一份
package org.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@SpringBootApplication
@EnableEurekaClient
public class Client8001Application {
public static void main(String[] args) {
SpringApplication.run(Client8001Application.class,args);
}
}
4、其他java类
Controller类
package org.example.controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HelloController {
@GetMapping("/hello/{name}")
public String hello(@PathVariable String name){
return "hello,"+name;
}
}
package example.controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
@RestController
public class HelloController {
@GetMapping("/hello/{name}")
public String hello(@PathVariable String name){
return "hello2,"+name;
}
}
两个服务的Controller类实际上应该是一样的，此处为了演示负载均衡，稍作修改一个为“return "hello,"+name;”，另一个为“return "hello2,"+name;”
二、代码示例
说明：此处使用的SpringBoot版本为2.1.13.RELEASE，SpringCloud版本为Greenwich.SR5
SpringCloud实现负载均衡比较简单 ，只需要在RestTemplate类上加上一个注解@LoadBalanced,并修改下RestTemplate调用方式，原始使用的是url直接调用，现在改为通过服务调用
1、maven依赖
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<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-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
2、application.yml
server:
port: 9002
spring:
application:
name: ribbon
eureka:
instance:
hostname: localhost
prefer-ip-address: true
instance-id: ribbon-9002
client:
service-url:
defaultZone: http://eureka7001:7001/eureka/,http://eureka7002:7002/eureka/,http://eureka7003:7003/eureka/
#info信息
info:
app:
name: ribbon-9002
company:
name: www.xxx.com
build:
artifactId: ${project.artifactId}
version: ${project.version}
3、启动类
package org.example;
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 Ribbon9002Application {
public static void main(String[] args) {
SpringApplication.run(Ribbon9002Application.class,args);
}
@Bean
@LoadBalanced
RestTemplate restTemplate(){
return new RestTemplate();
}
}
4、其他java类
Controller
调用地址格式：http://{服务}/hello/name
package org.example.controller;
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.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
public class HelloController {
@Autowired
private RestTemplate restTemplate;
@GetMapping("/hello/{name}")
public String hello(@PathVariable String name){
return restTemplate.getForObject("http://client/hello/"+name,String.class);
}
}
2、测试验证
先后启动server、client、consumer,访问http://localhost:7001/
image.png
多次访问http://localhost:9002/hello/zs
交替出现
image.png
image.png
SpringCloud默认使用轮询策略进行负载均衡，如果想修改策略，只需要增加IRue注入到Spring容器
@Bean
IRule iRule(){
return new RandomRule();//IRule实现类，此处为随机
}
再次多次访问http://localhost:9002/hello/zs，不再试交替出现“hello,zs”和“hello2,zs”，而是随机出现
我们也可以自己定义负载均衡算法，大家可以参照：https://blog.csdn.net/www1056481167/article/details/81151064
github:
https://github.com/panli1988/cloud01
https://github.com/panli1988/cloud02
参考：
https://blog.csdn.net/forezp/article/details/70148833
http://www.itmuch.com/spring-cloud/spring-cloud-index/
还有尚硅谷周阳老师的视频
