搭建springcloud微服务（三）负载均衡

在调用方springcloud-account微服务项目的controller中增加负载均衡：

 SpringcloudAccountApplication :     RestTemplate上添加@LoadBalanced 

package com.org.springcloudaccount;

import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.bus.event.RefreshListener;
import org.springframework.cloud.client.SpringCloudApplication;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
//@EnableDiscoveryClient
//@EnableFeignClients
//@EnableHystrix
public class SpringcloudAccountApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringcloudAccountApplication.class, args);
    }
    @Bean
    @LoadBalanced        // 开启负载均衡
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }

}

package com.org.springcloudaccount;

import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class MyController {
    @Autowired
    private RestTemplate restTemplate;

    @RequestMapping("/a2b")
    public String memTest() {
        String str = restTemplate.getForObject("http://bill-server/billTest", String.class);
        return str;
    }
}

创建springboot项目springcloud-bill，方式同eureka，并且注册到eureka上

application.yaml

eureka:
  client:
    serviceUrl:
#      eureka的注册中心地址
      defaultZone: http://localhost:8888/eureka/
server:
#  此项目端口号
  port: 8890
spring:
  application:
#    注册进eureka的名字
    name: bill-server

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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.3.1.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.org</groupId>
    <artifactId>springcloud-bill</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springcloud-bill</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
        <spring-cloud.version>Hoxton.SR6</spring-cloud.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-zipkin</artifactId>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>${spring-cloud.version}</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

MyController ： 

package com.org.springcloudbill;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MyController {
    @RequestMapping("billTest")
    public String orderTest(){
        String instance = System.getProperty("instance");
        return "this is bill"+System.currentTimeMillis()+"--" +instance;
    }
}

 SpringcloudBillApplication ：

@SpringBootApplication
@EnableEurekaClient
public class SpringcloudBillApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringcloudBillApplication.class, args);
    }

}

一个启动参数添加：

-Dinstance=11 -Dserver.port=8891

 另一个启动参数添加：

-Dinstance=22 -Dserver.port=8892

同时启动 springcloudbill-11和springcloudbill22两个微服务，以及springcloudaccount、springcloudeureka共4个微服务。

访问：http://localhost:8889/a2b

结果是有时候调用 11有时候调用22，证明负载均衡成功！

一个简单的负载均衡搭建完毕！