一，今天完成的事情

任务九

我选择的是任务三的Artstudio部分改成Spring Cloud展示，因为我要展示随机访问和OpenFeign的功能。其中包含 微服务A 使用 微服务B 的情况，更好展示Spring Cloud。

1，最终我的项目结构如下图：

2，我首先建立的是eureka，和之前一样，还是

server:
  port: 8761

3，一步步拆解，先完成最底层

artstudioimageserviceone

只有一个，不展示负载均衡。这个组件供其它service调用，原来在项目三中我是没给controller的。

spring:
  application:
    name: ArtstudioImageServer
  cloud:
    loadbalancer:
      ribbon:
        enabled: false
  datasource: #DB Configuration:
    driverClassName: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://localhost:3306/art_room?useUnicode=true&characterEncoding=utf8
    username: root
    password: root

server:
  port: 7011

eureka:
  password: password
  client:
    serviceUrl:
      defaultZone: http://user:${eureka.password}@localhost:8761/eureka/
  instance:
    leaseRenewalIntervalInSeconds: 10
    metadataMap:
      instanceId: ${vcap.application.instance_id:${spring.application.name}:${spring.application.instance_id:${server.port}}}

mybatis:
  #  mapper文件
  mapper-locations: mapper/*Dao.xml
  #  实体类
  type-aliases-package: com.nicole.imgs.entity

package com.nicole.studio.controller;

import com.nicole.studio.entity.ArtstudioImage;
import com.nicole.studio.service.ArtstudioImageService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/artstudioimgs")
public class ArtstudioImageController {
    private Logger logger = LoggerFactory.getLogger(ArtstudioImageController.class);

    /**
     * 服务对象
     */
    @Autowired
    private ArtstudioImageService artstudioImageService;

    @RequestMapping (value = "/{id}", method = RequestMethod.GET)
    @ResponseBody
    public List<ArtstudioImage> queryByArtstudioId(@PathVariable(name = "id") long id) {
        List<ArtstudioImage> artstudioImages = this.artstudioImageService.queryByArtstudioId(id);
        if ( null != artstudioImages ) {
            return artstudioImages;
        }
        return null;
    }
}

package com.nicole.studio;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

/**
 * @author Nicole
 */
@SpringBootApplication
@EnableDiscoveryClient
public class ArtstudioImageApplication {
    public static void main(String[] args) {
        SpringApplication.run(ArtstudioImageApplication.class, args);
    }
}

运行eureka和artstudioimageserviceone能找到服务

成功通过设置的7011接口访问

4，artstudioserviceone和artstudioservicetwo。这两个准备做负载均衡。

有

去调用这篇日志中的artstudioimageserviceone。

package com.nicole.studio.client;

import com.nicole.studio.entity.ArtstudioImage;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import java.util.List;

import static org.springframework.web.bind.annotation.RequestMethod.GET;

@FeignClient("ArtstudioImageServer")
public interface ArtstudioImageClient {

    @RequestMapping(method = RequestMethod.GET, value = "/artstudioimgs/{id}")
    List<ArtstudioImage> queryByArtstudioId(@PathVariable(name = "id") long id);
}

ArtstudioImageServer

一定要大小写正确，一字不差

所以需要改变的地方有，原来是：

现在变成：

import com.nicole.studio.client.ArtstudioImageClient;

和

@Autowired
private ArtstudioImageClient artstudioImageClient;

启动类中

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class ArtstudioApplication {
    public static void main(String[] args) {
        SpringApplication.run(ArtstudioApplication.class, args);
    }
}

注意加上

@EnableFeignClients

eureka能成功访问到1台

端口7111成功

server:
  port: 7111

端口7112eureka也正常注册，直接从7112访问也成功

server:
  port: 7112

5,客户端

OpenFeign

package com.nicole.artstudio.controller;

import com.nicole.artstudio.client.ArtstudioServerClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.Map;

@RestController
@RequestMapping("/client")
public class ClientController {
    @Autowired
    private ArtstudioServerClient artstudioServerClient;

    @RequestMapping (value = "/{id}", method = RequestMethod.GET)
    @ResponseBody
    public Map<String,Object> selectOne(@PathVariable(name = "id") long id) {
        return artstudioServerClient.selectOne(id);
    }
}

server:
  port: 7211

还没做负载均衡的时候，能够成功探测到client

从7211端口的client能正常访问。轮询方式

停止client。给client的controller加入

@RequestMapping("/random/{id}")

随机负载均衡访问的方式

package com.nicole.artstudio.controller;

import com.nicole.artstudio.client.ArtstudioServerClient;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.client.RestTemplate;

import java.util.Map;

@RestController
@RequestMapping("/client")
public class ClientController {
    private static final Logger LOGGER = LoggerFactory.getLogger(ClientController.class);
    @Autowired
    private ArtstudioServerClient artstudioServerClient;

    @Autowired
    RestTemplate template;

    /**
     * RoundRobin access with OpenFeign
     */
    @RequestMapping (value = "/{id}", method = RequestMethod.GET)
    @ResponseBody
    public Map<String,Object> selectOne(@PathVariable(name = "id") long id) {
        return artstudioServerClient.selectOne(id);
    }

    /**
     * Random access with load balancer of RestTemplate
     */
    @RequestMapping("/random/{id}")
    @ResponseBody
    public String random(@PathVariable(name = "id") long id) {
        String url = "http://ArtstudioServer/artstudio/"+id;
        String callmeResponse = template.getForObject(url, String.class);
        LOGGER.info("Response: {}", callmeResponse);
        return callmeResponse;
    }
}

多次点击都成功

如果为了在日志记录每次访问的接口，在artstudioservice层的controller加上

@Autowired
Environment environment;

变成

if ( null != artstudio  ) {
    return  Restful.set(200, "show artstudio successfully  "
            +environment.getProperty("local.server.port"), artstudio);
}

logger打印

LOGGER.info("Response: {}", callmeResponse);

是保持50%情况下的随机访问，成功

7，WEB部分还是通过Nginx配置两台随机访问；并且两台WEB可以随机访问两台Service（其中之一）。是任务七中已经完成过的功能。

二，今天问题

如果用Spring Cloud LoadBalancer的 RestTemplate的用法，这里的

template.getForObject(url, String.class);

和OpenFeign没有关系。但是OpenFeign是微服务的必要功能，能够提供接口访问方式。

三，今天的收获

至少有两台service，web能随机访问其中任意一台。

项目可以加入其它Spring Cloud组件，展示其它组件的集成用法。目前首选Spring Cloud Gateway。

四，明天的计划

任务九深度思考