SpringCloud五大组件

五大组件:Eureka(注册中心),

​ Ribbon/Feign(负载均衡),

​ Zuul(网关),

​ Config(配置中心),

​ Hystrix(熔断器)

注：本文章较长，但是五大组件全都包含

新建一个父模块，导包，包含SpringCloud以及SpringBoot的包

1.Eureka------注册中心

​ 1.1在SpringCloud官网 找到Eureka(How to includ Eureka)

​ 1.2新建模块Eureka，导包

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

​ 1.3application.yml

server:
  port: 1000
eureka:
  instance:
    hostname: localhost #主机
  client:
    registerWithEureka: false #禁止注册中心向自己注册
    fetchRegistry: false #禁止注册中心拉取注册地址清单
    serviceUrl: #微服务向注册中心注册的地址
      defaultZone: http://localhost:1000/eureka/

1.4在主配置类上打标签 @EnableEurekaServer 开启Eureka事务

package cn.itsource.springboot;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class EurekaApplication {

    public static void main(String[] args) {
        new SpringApplicationBuilder(EurekaApplication.class).web(true).run(args);
    }

}

2.EurekaServer高可用集群

​ 2.1为什么使用Eureka高可用集群？

​ 答：当只有一个EurekaServer，如果挂掉了，那么整个微服务都不可用，所以要进行集群

​ 2.2

在“我的电脑”C:\Windows\System32\drivers\etc这个路径下 添加两个peer1和peer2

​ 127.0.0.1 peer1
​ 127.0.0.1 peer2

​ 2.3 application.yml配置如下

spring:
  profiles:
    active: peer1
---
server:
  port: 1000
eureka:
  instance:
    hostname: peer1 #主机
  client:
    registerWithEureka: false #禁止注册中心向自己注册
    fetchRegistry: false #禁止注册中心拉取注册地址清单
    serviceUrl: #微服务向注册中心注册的地址
      defaultZone: http://peer2:1001/eureka/
spring:
  profiles: peer1
---
server:
  port: 1001
eureka:
  instance:
    hostname: peer2 #主机
  client:
    registerWithEureka: false #禁止注册中心向自己注册
    fetchRegistry: false #禁止注册中心拉取注册地址清单
    serviceUrl: #微服务向注册中心注册的地址
      defaultZone: http://peer1:1000/eureka/
spring:
  profiles: peer2

3.Ribbon

ribbon是负载均衡器，是基于RestTemplate ,它赋予了RestTemplate 负载均衡的能力

在客户端order中使用Ribbon

3.1导入jar包

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>
</dependency>

3.2 写一个类，里面写RestTemplate方法

​ RestTemplate简介: pring框架提供的RestTemplate类可用于在应用中调用rest服务，它简化了与http服务的通信方式，统一了RESTful的标准，封装了http链接， 我们只需要传入url及返回值类型即可。相较于之前常用的HttpClient，RestTemplate是一种更优雅的调用RESTful服务的方式。

package cn.itsource.springcloud.config;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.client.RestTemplate;

@Configuration
public class BeanConfig {

    //交给Bean管理
    //@LoadBalanced :让RestTemplate 有负载均衡的能力
    @Bean
    @LoadBalanced
    public RestTemplate restTemplate(){
        return new RestTemplate();
    }
}

3.3主配置类

package cn.itsource.springcloud;

import cn.itsource.springcloud.config.BeanConfig;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.context.annotation.Import;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@RestController
@Import(BeanConfig.class)
public class OrderApplication {
   
    public static void main(String[] args) {
        new SpringApplicationBuilder(OrderApplication.class).web(true).run(args);
    }

}

3.4 Controller层方法

@GetMapping("/order/user/{id}")
    public User getUserById(@PathVariable("id") Long id){
        //String url = "http://localhost:2000/user/"+id;
        String url = "http://user-server/user/"+id;
        User user = restTemplate.getForObject(url, User.class);
        return user;
    }

3.5 application.yml

eureka:
  client:
    serviceUrl:
      defaultZone: http://peer1:1000/eureka/,http://peer2:1001/eureka/
  instance:
    instance-id: first-one
    prefer-ip-address: true

server:
  port: 2000

spring:
  application:
    name: order

4.Feign

​ 简介：Feign是基于Ribbon，同样具有负载均衡的能力

4.1引入Feign的jar包

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

4.2 配置类打上标签 @EnableFeignClients(“cn.itsource.springcloud.feignclient”) feignclient是接口类的包名

package cn.itsource.springcloud;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableFeignClients("cn.itsource.springcloud.feignclient")
public class OrderApplication {

    public static void main(String[] args) {
        new SpringApplicationBuilder(OrderApplication.class).web(true).run(args);
    }
}

4.3 写一个接口类

package cn.itsource.springcloud.feignclient;

import cn.itsource.springcloud.domain.User;
import cn.itsource.springcloud.fallback.UserFeignClientFallback;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

//该客户端接口用来调用用户服务(user-server)
// http://user-server/userserver/user/11  -> ribbon
@FeignClient(value = "customer",fallback = UserFeignClientFallback.class)
public interface UserFeignClient {

    //调用根据id获取用户的接口
    @GetMapping("/userserver/user/{id}")
    User getUserById(@PathVariable("id") Long id);
}

4.4 再写一个实现类

package cn.itsource.springcloud.fallback;

import cn.itsource.springcloud.domain.User;
import cn.itsource.springcloud.feignclient.UserFeignClient;
import org.springframework.stereotype.Component;

@Component
public class UserFeignClientFallback implements UserFeignClient {

    @Override
    public User getUserById(Long id) {
        //返回托底数据
        return new User(-1L,"null","用户服务获取失败");
    }
}

4.5 Controller控制层调用接口类

package cn.itsource.springcloud.web.controller;

import cn.itsource.springcloud.domain.User;
import cn.itsource.springcloud.feignclient.UserFeignClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

//订单服务,消费者
@RestController
@RequestMapping("/orderserver")
public class OrderServerController {

    @Autowired
    private UserFeignClient userFeignClient ;

    //浏览器调用,根据id获取用户 : 有负载均衡
    @GetMapping("/user/{id}")
    public User getUserById(@PathVariable("id")Long id){
        return userFeignClient.getUserById(id);
    }
}

4.6 application.yml

eureka:
  client:
    serviceUrl:
      defaultZone: http://peer1:1000/eureka/,http://peer2:1001/eureka/
  instance:
    instance-id: order-second
    prefer-ip-address: true

server:
  port: 2001

spring:
  application:
    name: order-second

5.Hystrix

5.1 导包

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>

5.2 配置类打上注解标签(开启Hystrix)

@EnableCircuitBreaker

5.3 Controller控制层 (需在公共类上写一个AjaxResult)

package cn.itsource.springcloud.web.controller;


import cn.itsource.springcloud.domain.User;
import cn.itsource.springcloud.utils.AjaxResult;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
@RequestMapping("/orderserver")
public class OrderController {

    @Autowired
    private RestTemplate restTemplate;

    //这是订单服务，调用用户服务
    @HystrixCommand(fallbackMethod = "getUserByIdFallback")
    @GetMapping("/user/{id}")
    public AjaxResult getUserById(@PathVariable("id")Long id){
        String url = "http://customer/userserver/user/"+id;
        //customer是yml配置中application.name名
        //userserver是控制层的mapping
        User user = restTemplate.getForObject(url, User.class);

        AjaxResult ajaxResult = new AjaxResult();
        ajaxResult.getData(user);
        return ajaxResult;
    }

    //编写降级方法
    public AjaxResult getUserByIdFallback(@PathVariable("id")Long id){
        AjaxResult ajaxResult = new AjaxResult();
        ajaxResult.setSuccess(false);
        ajaxResult.setErroMessage("抱歉，订单服务不可能");
        return ajaxResult;
    }
}

5.4 application.yml

eureka:
  client:
    serviceUrl:
      defaultZone: http://peer1:1000/eureka/,http://peer2:1001/eureka/
  instance:
    instance-id: first-one
    prefer-ip-address: true

server:
  port: 2000

spring:
  application:
    name: order

6.Zuul网关

6.1 导入jar包

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-netflix-zuul</artifactId>
</dependency>

6.2 主配置类上打注解标签 @EnableZuulProxy//开启zuul网关

package cn.itsource.springcloud;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
import org.springframework.web.bind.annotation.RestController;

@EnableZuulProxy//开启zuul网关
@SpringBootApplication
@RestController
public class ZuulApplication {


    public static void main(String[] args) {
        new SpringApplicationBuilder(ZuulApplication.class).web(true).run(args);
    }
}

6.3 application.yml

eureka:
  client:
    serviceUrl:
      defaultZone: http://peer1:1000/eureka/,http://peer2:1001/eureka/
  instance:
    instance-id: first-one
    prefer-ip-address: true

server:
  port: 4000

spring:
  application:
    name: zuul-server

zuul:
  routes:
    order: "/order/**" #别名---order是订单服务yml中application.name的名字
  prefix: "/pre" #前缀
  
  #浏览器访问格式：http://localhost:4000/pre/order/orderserver/user/10

6.4 写一个过滤器的类，继承ZuulFilter,实现登录检查

package cn.itsource.springcloud.filter;

import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;
import com.netflix.zuul.exception.ZuulException;
import org.apache.commons.lang.StringUtils;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.HashMap;

public class ZuulByFilter extends ZuulFilter{

    //过滤器的类型 PRE_TYPE
    @Override
    public String filterType() {
        return "pre";
    }

    //过滤器的顺序
    @Override
    public int filterOrder() {
        return 1;
    }

    @Override
    public boolean shouldFilter() {

        //获取请求上下文
        RequestContext currentContext = RequestContext.getCurrentContext();
        //获取请求对象
        HttpServletRequest request = currentContext.getRequest();
        //获取请求的地址
        String requestURI = request.getRequestURI();
        //如果包含了login，则返回false
        if (requestURI.toUpperCase().contains("LOGIN")){
            return false;
        }
        return true;
    }

    //执行run方法-----中心方法
    @Override
    public Object run() throws ZuulException {

        //获取上下文对象
        RequestContext currentContext = RequestContext.getCurrentContext();
        //获取对象
        HttpServletRequest request = currentContext.getRequest();
        //获取相应对象
        HttpServletResponse response = currentContext.getResponse();

        //获取响应的数据格式
        response.setContentType("application/json;charset:utf-8");
        //获取请求头x-token
        String token = response.getHeader("x-token");
        //如果不存在请求头，则让重新登录
        if (StringUtils.isBlank(token)){
            HashMap<String,String> map = new HashMap<>();
            map.put("success", "false");
            map.put("errorMessage","麻烦请登录" );
            currentContext.setSendZuulResponse(false);
        }
        return null;
    }
}

7.Config

7.1 导入jar包

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-config-server</artifactId>
</dependency>

7.2 主配置类打上注解标签

package cn.itsource.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.config.server.EnableConfigServer;

//@EnableDiscoveryClient
//@EnableConfigServer :开启配置中心
@SpringBootApplication
@EnableConfigServer
public class ConfigServerApplication5000 {
    public static void main(String[] args) {
        SpringApplication.run(ConfigServerApplication5000.class);
    }
}

7.3 application.yml (放在码云仓库中)

server:
  port: 5000
spring:
  application:
    name: config-server
    
  #码云仓库地址
  cloud:
    config:
      server:
        git:
          uri: https://gitee.com/xxxxx/zuul-server.git  #码云仓库
          username: xxxxx
          password: xxxxx

eureka:
  client:
    serviceUrl:
      defaultZone: http://peer1:1000/eureka/,http://peer2:1001/eureka/
  instance:
    prefer-ip-address: true #使用ip注册到注册中心
    instance-id: config-server:5000 #指定服务的id

7.4 浏览器访问地址: localhost:5000/application-config-dev.yml

实际要看码云中仓库名