从零搭建springcloud

开发工具：IDEA

JDK1.8

sprngcloud微服务的架构基础 ：生产者（client），消费者（client），注册中心/配置中心（server）

首先我们创建server，打开idea，选择左侧spring initializr,点击next

springcloud是以eureka作为注册中心 ,这里要勾选Eureka Server

一直next创建

pom.xml如下,注意要修改springboot与springcloud版本，否则springboot版本太高版本不匹配会爆红报错，建议按照以下配置来。

<?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>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>server</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>server</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    </properties>
    <!-- 导入eureka依赖 -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
    </dependencies>
    <!-- dependency management -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Dalston.SR1</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>

在application.properties配置文件里配置eureka

server.port=8081
eureka.instance.hostname=localhost
#在默认设置下， 该服务注册中心也会将自己作为客户端来尝试注册它自己，所以我们需要禁用它的客户端注册行为
eureka.client.registerWithEureka=false
eureka.client.fetchRegistry=false
eureka.client.serviceUrl.defaultZone=http://${eureka.instance.hostname}:${server.port}/eureka/

在启动类上添加

@EnableEurekaServer

启动项目，访问http://localhost:8081

二.创建生产者provider1

新建springboot项目与注册中心server创建一样，pom.xml如下

<?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>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>provider1</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>provider1</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    </properties>
    <!-- 导入eureka依赖 -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
    </dependencies>
    <!-- dependency management -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Dalston.SR1</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>

application.properties，注意端口不能跟server服务端口一样，eureka地址端口要与server服务一样。

server.port=8082
eureka.client.serviceUrl.defaultZone=http://localhost:8081/eureka/
#服务名称
spring.application.name=provider1

启动类上添加

@EnableEurekaClient

创建controller写一个提供方法

import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import java.util.HashMap;
import java.util.Map;
@RestController
public class controller {
    /**
     * 假如这个客户端要提供一个getCloud的方法
     * @return
     */
    @GetMapping(value = "/getCloud")
    @ResponseBody
    public Map<String,Object> getCloud(@RequestParam String name){
        Map<String,Object> data = new HashMap<>();
        data.put("userName",name);
        data.put("from","provider-A");
        return data;
    }
}

启动项目，可见在注册中心已经注册上了

然后我们访问provider1服务

三.创建消费者(customer)

新建springboot项目与注册中心server创建一样，pom.xml如下

<?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>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>customer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>customer</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    </properties>
    <!-- 导入eureka依赖 -->
    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-eureka-server</artifactId>
        </dependency>
    </dependencies>
    <!-- dependency management -->
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Dalston.SR1</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>

application.properties

server.port=8083
eureka.client.serviceUrl.defaultZone=http://localhost:8081/eureka/
spring.application.name=customer1

启动类上添加

@EnableEurekaClient

创建消费方法

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
import java.util.HashMap;
import java.util.Map;
@RestController
public class customerController {
    @Autowired
    RestTemplate restTemplate;
    /**
     * 实例化RestTemplate
     * @return
     */
    @LoadBalanced
    @Bean
    public RestTemplate rest() {
        return new RestTemplate();
    }
    /**
     * Rest服务端使用RestTemplate发起http请求,然后得到数据返回给前端
     * @param name
     * @return
     */
    @GetMapping(value = "/gotoCloud")
    @ResponseBody
    public Map<String,Object> gotoCloud(@RequestParam String name){
        Map<String,Object> data = new HashMap<>();
        /**
         * 因为他向注册中心注册了服务，服务名称provider1,我们访问provider1即可
         */
        data = restTemplate.getForObject("http://provider1/getCloud?name="+name,Map.class);
        return data;
    }
}

启动消费者，可以看到消费者也注册上了

访问http://localhost:8083/gotoCloud?name=wangsheng，可以看到调用了提供者的服务。

那么怎么实现负载均衡呢？

我们把provider1复制一份，修改 application.properties，将端口改为8084，spring.application.name不变

server.port=8084
eureka.client.serviceUrl.defaultZone=http://localhost:8081/eureka/
#服务名称
spring.application.name=provider1

将提供者里面的方法稍微修改一下

然后启动

可以看到provider1有2个实例。

我们再次访问http://localhost:8083/gotoCloud?name=wangsheng

一开始是from A,你刷新一下 变成 from B了，说明这个时候两台提供者在交替工作，从而达到了一个负载均衡的作用。