手把手带你创建微服务项目

1.先创建以下项目结构

 2.在父项目中导入以下依赖

    
        
            org.springframework.boot
            spring-boot-starter
        

        
        
            org.springframework.boot
            spring-boot-starter-web
        
        
        
            org.springframework.boot
            spring-boot-starter-logging
        
        
        
            org.projectlombok
            lombok
            1.18.4
            provided
        
        
        
            org.springframework.boot
            spring-boot-starter-actuator
        
        
        
            org.springframework.boot
            spring-boot-devtools
            true
        

        
            org.springframework.boot
            spring-boot-starter-test
            test
        
    
    
        
            
                com.alibaba.cloud
                spring-cloud-alibaba-dependencies
                2.1.0.RELEASE
                pom
                import
            
            
            
            
                org.springframework.cloud
                spring-cloud-dependencies
                Greenwich.RELEASE
                pom
                import
            
            
            
                com.sun.xml.bind
                jaxb-core
                2.2.11
            
            
                javax.xml.bind
                jaxb-api
            
            
                com.sun.xml.bind
                jaxb-impl
                2.2.11
            
            
                org.glassfish.jaxb
                jaxb-runtime
                2.2.10-b140310.1920
            
            
                javax.activation
                activation
                1.1.1
            
            
        
    

    
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
        
    

 3.分别product，page项⽬的pom.xml⽂件中引⼊ Nacos客户端依赖，必须删除这三个项-client依赖。

   
        com.example
        yx-service-common
        0.0.1-SNAPSHOT
    

    
        com.alibaba.cloud
        spring-cloud-starter-alibaba-nacos-discovery
    

4。在product编写启动类

@SpringBootApplication
@MapperScan("com.qf.product.mapper")
//@EnableDiscoveryClient  //将当前的项目标记为注册中心的客户端，然后向注册信息
public class ProductApplication9000 {
    public static void main(String[] args) {
        SpringApplication.run(ProductApplication9000.class,args);
    }
}

5.在common中pom文件中添加以下依赖

  
        
            com.baomidou
            mybatis-plus-boot-starter
            3.3.2
        
        
        
            javax.persistence
            javax.persistence-api
            2.2
        
        
            mysql
            mysql-connector-java
            runtime
        
    

    
        yx-service-common
        
            
                
                    maven-clean-plugin
                    3.1.0
                
                
                
                    maven-resources-plugin
                    3.0.2
                
                
                    maven-compiler-plugin
                    3.8.0
                
                
                    maven-surefire-plugin
                    2.22.1
                
                
                    maven-war-plugin
                    3.2.2
                
                
                    maven-install-plugin
                    2.5.2
                
                
                    maven-deploy-plugin
                    2.8.2
                
            
        
    

6.在product中的application.yml中导入yml文件

server:
  port: 9000
spring:
  application:
    name: yx-service-product
  datasource:
    url: jdbc:mysql://localhost:3306/yx_sc?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
    username: root
    password: 123
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848 #Nacos Server地址

7.在page的pom中，导入以下依赖

    

        
            com.example
            spring-clound-common
            0.0.1-SNAPSHOT
        


        
        
            org.springframework.cloud
            spring-cloud-starter-netflix-hystrix
        

        
            org.springframework.cloud
            spring-cloud-starter-openfeign
        
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-nacos-discovery
        
        
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-nacos-config
        
     
        
            com.alibaba.cloud
            spring-cloud-starter-alibaba-sentinel
        
    

8.编写page的启动类

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
//@EnableCircuitBreaker//开启Hystri熔断器功能
@EnableFeignClients//开启Feign远程服务调用功能
@MapperScan("com.qf.product.mapper")
//申明当前项目是Eurekaa客户端
@EnableDiscoveryClient
public class PageApplication {
    public static void main(String[] args) {
            SpringApplication.run(PageApplication.class,args);
   }
//   @LoadBalanced //调用Ribbon复杂均衡算法，实现负载均衡
//   @Bean
//    public RestTemplate restTemplate(){
//        return new RestTemplate();
//    }

}

9.编写page的yml文件

server:
  port: 9100
spring:
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848 #Nacos Server地址
      config:
        server-addr: 127.0.0.1:8848
      #group: DEFAULT_GROUP # 如果使⽤的默认分组，可以不设置
        file-extension: yaml
        ext-config[0]:
          data-id: test1.yaml
          #group: DEFAULT_GROUP
          refresh: true # 开启扩展dataId的动态刷新
        ext-config[1]:
          data-id: test2.yaml
          #group: DEFAULT_GROUP
          refresh: true # 开启扩展dataId的动态刷新

  application:
    name: yx-service-page

  datasource:
    url: jdbc:mysql://localhost:3306/yx_sc?useSSL=false&useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
    username: root
    password: 123

hystrix:
  command:
    default:   #就算不给也不报错有默认
      circuitBreaker:
        # 强制打开熔断器，如果该属性设置为true，强制断路器进入打开状态，将会拒绝所有的请求，默认false关闭的
        forceOpen: false
        # 触发熔断错误比例阈值，默认值50%
        errorThresholdPercentage: 50
        # 熔断后休眠时长，默认值5秒
        sleepWindowInMilliseconds: 3000
        # 熔断触发最小请求次数，默认值是20
        requestVolumeThreshold: 2
      execution:
        isolation:
          thread:
            # 熔断超时设置，默认为1秒
            timeoutInMilliseconds: 2000
  threadpool: #hytix线程池配置
    default:
      coreSize: 10 # 并发执⾏的最⼤线程数，默认10
      maxQueueSize: 1000 # BlockingQueue的最⼤队列数，默认值-1
      # 即使maxQueueSize没有达到，达到queueSizeRejectionThreshold该值后，请求也会被拒绝，默认值5
      queueSizeRejectionThreshold: 800

  # 暴露健康接口的细节
  endpoint:
    health:
      show-details: always
# 针对的被调⽤⽅微服务名称，不加就是全局⽣效
yx-service-product:
  ribbon:
  # 请求连接超时时间
    ConnectTimeout: 2000
  # 请求处理超时时间
    ReadTimeout: 10000
  # 对所有操作都进⾏重试
    OkToRetryOnAllOperations: true
  # 根据如上配置，当访问到故障请求的时候，它会再尝试访问⼀次当前实例(次数由MaxAutoRetries配置)，如果不⾏，
  # 就换⼀个实例进⾏访问；如果还不⾏，再换⼀次实例访问(更换次数由MaxAutoRetriesNextServer配置)；如果依然不⾏，返回失败信息。
    MaxAutoRetries: 0 # 对当前选中实例重试次数，不包括第⼀次调⽤
    MaxAutoRetriesNextServer: 0 # 切换实例的重试次数
    NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule # 负载策略调整
# 开启Feign的熔断功能
feign:
  hystrix:
    enabled: true  # 开启Feign的熔断功能
  compression:
    request:
      enabled: true # 默认不开启
      mime-types: text/html,application/xml,application/json # 设置压缩的数据类型，设置为默认值
      min-request-size: 2048 # 设置触发压缩的大小下限，2048为默认值
    response:
      enabled: true # 默认不开启
      # ⽅式1：暴露指定refresh端⼝
        # ⽅式1：暴露指定refresh端⼝
management:
  endpoints:
    web:
      exposure:
        include: bus-refresh

10.编写page的feign接口

package com.yx.erureka.feign;

import com.qf.common.pojo.Products;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

// 注解表示Feign的远程调用
//-name:表示feign远程调用对应的服务提供者的名称\

/**
 * fallback:如果出现错误，哪哪个回退的方法从新指定
 */
@FeignClient(name = "yx-service-product",fallback = ProductFeignImp.class)
public interface ProductFeign {
    //载该接口中定义抽象方法，每一个抽象方法映射一个对应远程请求处理方法，注意要与远程处理方法的结构保持一致
@RequestMapping("/product/DD/{id}")
Products findById(@PathVariable Integer id);
@RequestMapping("/server/query_port")
 String findProductServerPort();
}

编写错误返回内容

package com.yx.erureka.feign;

import com.qf.common.pojo.Products;
import org.springframework.stereotype.Component;

@Component
public class ProductFeignImp implements ProductFeign{
    @Override
    public Products findById(Integer id) {
        return null;
    }

    @Override
    public String findProductServerPort() {
        return "-2";
    }
}