springcloud+springcloudAlibaba(1) 微服务构建以及Eureka
| 技术 | 版本 |
|---|---|
| cloud | Hoxton.SR1 |
| boot | 2.2.2.RELEASE |
| cloud alibaba | 2.1.0.RELEASE |
| java | 1.8 |
| maven | 3.5 |
| mysql | 5.7 |
1. 新建Maven父工程
cloud2020 maven架构选择org.apache.maven.archetypes:maven-archetype-site
pom.xml代码如下
<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>
<groupId>com.atguigu.springcloudgroupId>
<artifactId>cloud2020artifactId>
<version>1.0-SNAPSHOTversion>
<packaging>pompackaging>
<name>Mavenname>
<url>http://maven.apache.org/url>
<inceptionYear>2001inceptionYear>
<distributionManagement>
<site>
<id>websiteid>
<url>scp://webhost.company.com/www/websiteurl>
site>
distributionManagement>
<properties>
<project.build.sourceEncoding>UTF-8project.build.sourceEncoding>
<maven.compiler.source>1.8maven.compiler.source>
<maven.compiler.target>1.8maven.compiler.target>
<junit.version>4.12junit.version>
<log4j.version>1.2.17log4j.version>
<lombok.version>1.16.18lombok.version>
<mysql.version>5.1.47mysql.version>
<druid.version>1.1.16druid.version>
<mybatis.spring.boot.version>1.3.0mybatis.spring.boot.version>
properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-dependenciesartifactId>
<version>2.2.2.RELEASEversion>
<type>pomtype>
<scope>importscope>
dependency>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-dependenciesartifactId>
<version>Hoxton.SR1version>
<type>pomtype>
<scope>importscope>
dependency>
<dependency>
<groupId>com.alibaba.cloudgroupId>
<artifactId>spring-cloud-alibaba-dependenciesartifactId>
<version>2.1.0.RELEASEversion>
<type>pomtype>
<scope>importscope>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
<version>${mysql.version}version>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>druidartifactId>
<version>${druid.version}version>
dependency>
<dependency>
<groupId>org.mybatis.spring.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
<version>${mybatis.spring.boot.version}version>
dependency>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
<version>${junit.version}version>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<version>${lombok.version}version>
<optional>trueoptional>
dependency>
dependencies>
dependencyManagement>
<build>
<plugins>
<plugin>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-maven-pluginartifactId>
<configuration>
<fork>truefork>
<addResources>trueaddResources>
configuration>
plugin>
plugins>
build>
project>
2. 建立支付module: cloud-provider-payment8001
项目结构：
2.1 pom.xml如下：
<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>cloud2020artifactId>
<groupId>com.atguigu.springcloudgroupId>
<version>1.0-SNAPSHOTversion>
parent>
<modelVersion>4.0.0modelVersion>
<artifactId>cloud-provider-payment8001artifactId>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-actuatorartifactId>
dependency>
<dependency>
<groupId>org.mybatis.spring.bootgroupId>
<artifactId>mybatis-spring-boot-starterartifactId>
dependency>
<dependency>
<groupId>com.alibabagroupId>
<artifactId>druid-spring-boot-starterartifactId>
<version>1.1.10version>
dependency>
<dependency>
<groupId>mysqlgroupId>
<artifactId>mysql-connector-javaartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-jdbcartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-devtoolsartifactId>
<scope>runtimescope>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
dependencies>
project>
2.2 application.yml
server:
port: 8001
spring:
application:
name: cloud-provider-service
datasource:
type: com.alibaba.druid.pool.DruidDataSource #当前数据源操作类型
driver-class-name: org.gjt.mm.mysql.Driver #mysql驱动包
url: jdbc:mysql://localhost:3306/db2019?useUnicode=true&characterEncoding-utr-8&useSSL=false
username: root
password: root
mybatis:
mapper-locations: classpath:mapper/*.xml
type-aliases-package: com.atguigu.springcloud.entities #所有Entity别名类所在包
2.3 主启动类 PaymentMain8001
package com.atguigu.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class PaymentMain8001 {
public static void main(String[] args) {
SpringApplication.run(PaymentMain8001.class,args);
}
}
2.4 数据库
建库：
CREATE TABLE `payment`(
`id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT 'ID',
`serial` varchar(200) DEFAULT '',
PRIMARY KEY (`id`)
) ENGING=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8
2.5 业务类
//主实体类 Payment
package com.atguigu.springcloud.entities;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Payment {
private Long id;
private String serial;
}
//Json封装体CommentResult,传给前端，判断编码是否成功，成功才显示
package com.atguigu.springcloud.entities;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class CommonResult<T> { //泛型：如果装的payment 返回payment,装的order 返回order
private Integer code;
private String message;
private T data;
public CommonResult(Integer code,String message){
this(code,message,null);
}
}
//PaymentDao
package com.atguigu.springcloud.dao;
import com.atguigu.springcloud.entities.Payment;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
@Mapper
public interface PaymentDao {
int create(Payment payment);
Payment getPaymentById(@Param("id") Long id);
}
<mapper namespace="com.atguigu.springcloud.dao.PaymentDao">
<insert id="create" parameterType="Payment" useGeneratedKeys="true" keyProperty="id">
insert into payment(serial) values(#{serial})
insert>
<resultMap id="BaseResultMap" type="com.atguigu.springcloud.entities.Payment">
<id column="id" property="id" jdbcType="BIGINT"/>
<result column="serial" property="serial" jdbcType="VARCHAR"/>
resultMap>
<select id="getPaymentById" parameterType="Long" resultMap="BaseResultMap">
select * from payment where id=#{id};
select>
mapper>
//PaymentService
package com.atguigu.springcloud.service;
import com.atguigu.springcloud.entities.Payment;
import org.apache.ibatis.annotations.Param;
public interface PaymentService {
public int create(Payment payment);
public Payment getPaymentById(@Param("id") Long id);
}
//PaymentServiceImpl
package com.atguigu.springcloud.service;
import com.atguigu.springcloud.dao.PaymentDao;
import com.atguigu.springcloud.entities.Payment;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
@Service
public class PaymentServiceImpl implements PaymentService{
@Resource
private PaymentDao paymentDao;
public int create(Payment payment){
return paymentDao.create(payment);
}
public Payment getPaymentById(Long id){
return paymentDao.getPaymentById(id);
}
}
//PaymentController
package com.atguigu.springcloud.controller;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import com.atguigu.springcloud.service.PaymentService;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.annotation.Resource;
@RestController
@Slf4j
public class PaymentController {
@Resource
private PaymentService paymentService;
//只传给前端CommonResult，不需要前端了解其他的组件
@PostMapping(value = "/payment/create")
public CommonResult create(Payment payment){
int result = paymentService.create(payment);
log.info("*****插入结果："+result);
if(result > 0){
return new CommonResult(200,"插入数据成功",result);
}else{
return new CommonResult(444,"插入数据失败",null);
}
}
@GetMapping(value = "/payment/get/{id}")
public CommonResult getPaymentById(@PathVariable("id") Long id){
Payment payment = paymentService.getPaymentById(id);
log.info("*****插入结果："+payment);
if(payment != null){
return new CommonResult(200,"查询成功",payment);
}else{
return new CommonResult(444,"没有对应记录,查询ID："+id,null);
}
}
}
2.6测试
Chrom浏览器可能不支持Post请求，可以使用PostMan工具测试,或者idea自带测试工具tools-Http client- Test Restful web service ,或者使用Swagger进行测试
总结： 1. 建module 2. 改pom 3. 写yml 4. 主启动 5. 业务类
3. 建立消费者订单module:
3.1 pom.xml
<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>cloud2020artifactId>
<groupId>com.atguigu.springcloudgroupId>
<version>1.0-SNAPSHOTversion>
parent>
<modelVersion>4.0.0modelVersion>
<artifactId>cloud-consumer-order80artifactId>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-actuatorartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-devtoolsartifactId>
<scope>runtimescope>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
dependencies>
project>
3.2 application.yml
server:
port: 80
3.3 主启动
package com.atguigu.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class OrderMain80 {
public static void main(String[] args) {
SpringApplication.run(OrderMain80.class,args);
}
}
3.4业务类
订单也需要Payment、CommonResult实体类，但是不需要操作数据库，没有Service、Dao，只需添加Controller即可。
//Payment
package com.atguigu.springcloud.entities;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class Payment {
private Long id;
private String serial;
}
//CommonResult
package com.atguigu.springcloud.entities;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
@Data
@AllArgsConstructor
@NoArgsConstructor
public class CommonResult<T> { //泛型：如果装的payment 返回payment,装的order 返回order
private Integer code;
private String message;
private T data;
public CommonResult(Integer code,String message){
this(code,message,null);
}
}
首说RestTemplate： RestTemplate提供了多种便捷访问远程Http服务的方法，是一种简单便捷的访问restful服务模板类，是Spring提供的用于访问Rest服务的客户端模板工具集，实现80到8001的远程调用。
官网地址：
https://docs.spring.io/spring-framework/docs/5.2.2.RELEASE/javadoc-api/org/springframework/web/client/RestTemplate.html
使用：
使用restTemplate访问restful接口非常的简单粗暴，（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。
将RestTemplate对象注册到容器中
package com.atguigu.springcloud.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;
@Configuration
public class ApplicationContextConfig {
@Bean
public RestTemplate getRestTemplate(){
return new RestTemplate();
}
}
package com.atguigu.springcloud.controller;
import com.atguigu.springcloud.entities.CommonResult;
import com.atguigu.springcloud.entities.Payment;
import lombok.extern.slf4j.Slf4j;
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;
import javax.annotation.Resource;
@RestController
@Slf4j
public class OrderController {
private static final String PAYMENT_URL="http://localhost:8001";
@Resource
private RestTemplate restTemplate;
@GetMapping("/consumer/payment/create")
public CommonResult<Payment> create(Payment payment){
return restTemplate.postForObject(PAYMENT_URL+"/payment/create",payment,CommonResult.class);
}
@GetMapping("/consumer/payment/get/{id}")
public CommonResult<Payment> getPayment(@PathVariable("id") Long id){
return restTemplate.getForObject(PAYMENT_URL+"/payment/get/"+id,CommonResult.class);
}
}
3.5启动80、8001服务，测试
80服务调用8001服务，实现效果如下：
查询：
添加：
浏览器并没有返回错误，但是我们来看数据库：
可以看到数据库只插入主键，并没有插入内容，要在8001的PaymentController加@RequestBody注解。
然后就可以插入了
4. 工程重构
项目中存在相同的代码（entities包下的Payment.class和CommonResult.class）,造成代码冗余，可以进行重构。
通过Maven聚合父工程，把相同重复的代码移到公开公用的工程里面，还可以放第三方接口、工具类，统一调配使用。
4.1 建立公共module
4.2 pom.xml
<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>cloud2020artifactId>
<groupId>com.atguigu.springcloudgroupId>
<version>1.0-SNAPSHOTversion>
parent>
<modelVersion>4.0.0modelVersion>
<artifactId>cloud-api-commonsartifactId>
<dependencies>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-devtoolsartifactId>
<scope>runtimescope>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
<optional>trueoptional>
dependency>
<dependency>
<groupId>cn.hutoolgroupId>
<artifactId>hutool-allartifactId>
<version>5.1.0version>
dependency>
dependencies>
project>
4.3 将entities包复制到cloud-api-commons
4.4 使用Maven打包发布上传到公用本地库里
打开Maven窗口，执行clean测试一下，无误后出现BUILD SUCCESS，然后执行install
4.5 删除重复entities，引入maven install的jar包坐标即可使用。
<dependency>
<groupId>com.atguigu.springcloudgroupId>
<artifactId>cloud-api-commonsartifactId>
<version>${project.version}version>
dependency>
5.EurekaServer服务端安装
5.1建module cloud-eureka-server7001
5.2 pom.xml
<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>cloud2020artifactId>
<groupId>com.atguigu.springcloudgroupId>
<version>1.0-SNAPSHOTversion>
parent>
<modelVersion>4.0.0modelVersion>
<artifactId>cloud-eureka-server7001artifactId>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-serverartifactId>
dependency>
<dependency>
<groupId>com.atguigu.springcloudgroupId>
<artifactId>cloud-api-commonsartifactId>
<version>${project.version}version>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-actuatorartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-devtoolsartifactId>
<scope>runtimescope>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
dependency>
dependencies>
project>
5.3 application.yml
server:
port: 7001
eureka:
instance:
hostname: localhost #eureka服务端的实例名称
client:
#false表示不向注册中心注册自己
register-with-eureka: false
#false表示自己端就是注册中心，我的职责就是维护服务实例，并不需要去检索服务
fetch-registry: false
service-url:
#设置与Eureka Server交互的地址查询服务和注册服务都需要依赖这个地址
defaultZ4 one: http://${eureka.instance.hostname}:${server.port}/eureka/
#eureka.server.enable-self-preservation # 设为false，关闭自我保护
5.4 主启动类
package com.atguigu.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;
@SpringBootApplication
@EnableEurekaServer
public class EurekaMain7001 {
public static void main(String[] args) {
SpringApplication.run(EurekaMain7001.class,args);
}
}
这是个服务注册中心，主要干的活就是服务注册，不需要写业务类。
但是注意：Eureka有两个组件，一定要标清楚哪个是Server，哪个是Client。@EnableEurekaServer代表服务注册中心
5.5测试
出现上面图标，表示Eureka 服务端安装成功。No instances available表示当前没有服务注册进来
6. 单机Eureka构建：支付微服务8001入驻进eurekaServer
6.1将 Eureka-client 依赖引入，便于使用注解@EnableEurekaClient标注这是个Eureka Client端
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-clientartifactId>
dependency>
6.2 在application.yml添加Eureka相关配置
eureka:
client:
#表示是否将自己注册进EurekaServer默认为true
register-with-eureka: true
#是否从EurekaServer抓取已有的注册信息，默认为true。单节点无所谓，集群必须设置为true才能配合ribbon使用负载均衡
fetch-registry: true
service-url:
defaultZone: http://localhost:7001/eureka
6.3 主启动类添加注解@EnableEurekaClient
6.4 测试
注意： 要先启动EurekaServer
这样就注册进来了，入住进Eureka服务器的名称就是8001yml中配置的spring.application.name。红色警告是Eureka的自我保护机制，后面会详细说。
7. 单机Eureka构建：订单微服务入驻进eurekaServer
7.1 在pom添加 Eureka-client依赖
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-clientartifactId>
dependency>
7.2 在application.yml添加相关配置
spring:
application:
name: cloud-order-server
eureka:
client:
#表示是否将自己注册进EurekaServer默认为true
register-with-eureka: true
fetch-registry: true
service-url:
defaultZone: http://localhost:7001/eureka
7.3 主启动类添加注解@EnableEurekaClient
7.4 测试
PS： 先启动EurekaServer，7001服务，再启动服务提供者provider，8001服务
cloud-order-server服务以入住，查询功能也可以正常执行
8. EurekaServer集群环境构建
8.1 创建module cloud-eureka-server7002
8.2 pom.xml
<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>cloud2020artifactId>
<groupId>com.atguigu.springcloudgroupId>
<version>1.0-SNAPSHOTversion>
parent>
<modelVersion>4.0.0modelVersion>
<artifactId>cloud-eureka-server7002artifactId>
<dependencies>
<dependency>
<groupId>org.springframework.cloudgroupId>
<artifactId>spring-cloud-starter-netflix-eureka-serverartifactId>
dependency>
<dependency>
<groupId>com.atguigu.springcloudgroupId>
<artifactId>cloud-api-commonsartifactId>
<version>${project.version}version>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-webartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-actuatorartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-devtoolsartifactId>
<scope>runtimescope>
<optional>trueoptional>
dependency>
<dependency>
<groupId>org.projectlombokgroupId>
<artifactId>lombokartifactId>
dependency>
<dependency>
<groupId>org.springframework.bootgroupId>
<artifactId>spring-boot-starter-testartifactId>
<scope>testscope>
dependency>
<dependency>
<groupId>junitgroupId>
<artifactId>junitartifactId>
dependency>
dependencies>
project>
8.3 写yml之前修改映射文件
找到 C:\Windows\System32\drivers\etc路径下的hosts文件
8.4 修改7001和7002的application.yml
8.5 主启动类
package com.atguigu.springcloud;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
@SpringBootApplication
@EnableEurekaServer
public class EurekaMain7002 {
public static void main(String[] args) {
SpringApplication.run(EurekaMain7002.class,args);
}
}
8.6测试
启动7001、7002
使用域名映射：
同时看到Eureka图标，且7001指着7002，7002指着7001，说明Eureka集群搭建成功。
- 将两个微服务发布到Eureka集群配置中
只需修改application.yml
测试
PS： 先启动EurekaServer，7001/7002服务；再启动服务提供者provider，8001；再启动消费者，80
现在，就已经把支付服务8001、订单服务80注册进Eureka集群环境，调用也OK。
10. 支付提供者8001集群环境搭建
10.1 创建module cloud-provider-payment8002
10.2 pom.xml 同8001的 pom.xml 一样
10.3 写application.yml，注意改端口
10.4 主启动类和业务类直接从8001拷贝
10.5 修改8001和8002的controller，默认的负载均衡方式是轮询，看执行查询具体调用那台provider
10.6 测试
PS： 启动顺序：7001、7002、8001、8002、80
8001和8002也都访问正常，那如果我们用80访问呢？发现怎么刷新都是8001，这是因为我们的源程序地址是写死的：
单机版写死是没有问题的，但是现在有8001、8002了，所有不应该再关注具体的IP和端口，而是只认服务名称。代码修改为一下在试。
@RestController
@Slf4j
public class OrderController {
//private static final String PAYMENT_URL="http://localhost:8001";
//通过在eureka上注册过的微服务名称调用
private static final String PAYMENT_URL = "http://CLOUD-PROVIDER-SERVICE";
@Resource
private RestTemplate restTemplate;
@GetMapping("/consumer/payment/create")
public CommonResult<Payment> create(Payment payment){
return restTemplate.postForObject(PAYMENT_URL+"/payment/create",payment,CommonResult.class);
}
@GetMapping("/consumer/payment/get/{id}")
public CommonResult<Payment> getPayment(@PathVariable("id") Long id){
return restTemplate.getForObject(PAYMENT_URL+"/payment/get/"+id,CommonResult.class);
}
}
重新启动访问之后
发现报错了，现在对外暴露的不再是地址和端口，只认微服务名称了，可是微服务并不知道下面有几个，找不到这个主机名称，需要使用#LoadBalanced注解开启RestTemplate负载均衡功能。
提前说一下：这个就是后面要介绍的Ribbon负载均衡功能。
然后测试，多次刷新，就会发现8001、8002端口交替出现。
这样Ribbon和Eureka整合后Consumer可以直接调用服务而不用再关心地址和端口号，且该服务还有负载均衡功能了。O(∩_∩)O
这个架构是初级篇里面的重点，务必要学会，难的是后面的Alibaba的Nacos，也有服务注册和配置中心，Alibaba Nacos集群就比这个复杂了
Eureka集群原理
问题： 微服务RPC远程服务调用最核心的是什么?
高可用，试想你的注册中心只有一个only one，它出故障了那就呵呵o(￣︶￣)o了，会导致整个微服务环境不可用。
解决办法：搭建Eureka注册中心集群，实现负载均衡 + 故障容错
Eureka集群的原理：互相注册，相互守望。
一个Eureka集群包含7001和7002等许多服务，在这个集群中，7001指向其他所有服务，7002也指向其他所有服务。总之一句话：我自己一定要有我们这个圈子里的其他兄弟们的全部相关信息。 所以说，他们互相注册，相互守望，对外暴露出一个整体。
actuator微服务信息完善
主机名称：服务名称修改
当前问题：服务注册含有主机名称，要想按照规范的要求，只暴露服务名，不要出现主机名。
解决方法：找到application.yml，添加配置
访问信息有IP信息显示
当前问题：鼠标放在①上，在左下角②中没有IP显示。后续的话，这些微服务可能部署到几号机器上的，服务端口是多少，比如192.168.11.133机器上的8002端口，在调错或排错的时候，几号机器几号端口微服务名称就很明了。
解决方法：在application.yml添加配置
