10、Spring Boot分布式

1.分布式简介 

2.Zookeeper和Dubbo 

3.zookeeper

(1).zookeeper安装

官方文档：https://hub.docker.com/_/zookeeper?tab=description

在docker上安装zookeeper

[root@hosystem ~]# docker search zookeeper

NAME                               DESCRIPTION                                     STARS               OFFICIAL            AUTOMATED

zookeeper                          Apache ZooKeeper is an open-source server wh…   947                 [OK]

[root@hosystem ~]# docker pull zookeeper:3.4.11

(2).zookeeper启动

[root@hosystem ~]# docker images

REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE

zookeeper           3.4.11              56d414270ae3        2 years ago         146MB

[root@hosystem ~]# docker run --name ZK01 -p 2181:2181 --restart always -d 56d414270ae3

054d27805228d7d3cc6f8df96962a2dd9c24f3f5907554160854c661ef8d67dd

[root@hosystem ~]# docker ps

CONTAINER ID        IMAGE                   COMMAND                  CREATED             STATUS              PORTS                                                                                                         NAMES

054d27805228        56d414270ae3            "/docker-entrypoint.…"   41 seconds ago      Up 21 seconds       2888/tcp, 0.0.0.0:2181->2181/tcp, 3888/tcp                                                                    ZK01

#将2181端口添加到防火墙

[root@hosystem ~]# firewall-cmd --permanent --zone=public --add-port=2181/tcp

success

[root@hosystem ~]# firewall-cmd --reload

success

(3).zookeeper整合dubbo

[1].创建项目

①.创建Empty Project

②.New Module

创建provider

创建consumer

4.Spring Boot和Spring Cloud

Martin Fowler 微服务原文 https://martinfowler.com/articles/microservices.html 

(1).创建工程

[1].创建Empty Project

[2].创建eureka-server

[3].创建provider-ticket

[4].创建consumer-user

(2).配置eureka-server信息

[1].application.properties

server.port=8761

eureka.instance.hostname=eureka-server

eureka.client.register-with-eureka=false

eureka.client.fetch-registry=false

eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

[2].EurekaServerApplication.java

package com.hosystem.eurekaserver;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

/**

 *     注册中心

 *     1.配置Eureka信息

 *     2.@EnableEurekaServer

 */

@EnableEurekaServer

@SpringBootApplication

public class EurekaServerApplication {

public static void main(String[] args) {

SpringApplication.run(EurekaServerApplication.class, args);

}

}

访问eureka页面

(3).配置provider-ticket信息

[1].8001

①.TicketController.java

package com.hosystem.providerticket.controller;

import com.hosystem.providerticket.service.TicketService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class TicketController {

@Autowired

TicketService ticketService;

@GetMapping("/ticket")

public String getTicket(){

System.out.println("8001");

return ticketService.getTicket();

}

}

②.TicketService.java

package com.hosystem.providerticket.service;

import org.springframework.stereotype.Service;

@Service

public class TicketService {

public String getTicket(){

return "《模仿游戏》";

}

}

③.application.properties

server.port=8001

spring.application.name=provider-ticket

#注册服务的时候使用服务的ip地址

eureka.instance.prefer-ip-address=true

eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

[2].8002

①.TicketController.java

package com.hosystem.providerticket.controller;

import com.hosystem.providerticket.service.TicketService;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RestController;

@RestController

public class TicketController {

@Autowired

TicketService ticketService;

@GetMapping("/ticket")

public String getTicket(){

System.out.println("8002");

return ticketService.getTicket();

}

}

②.TicketService.java

package com.hosystem.providerticket.service;

import org.springframework.stereotype.Service;

@Service

public class TicketService {

public String getTicket(){

return "《模仿游戏》";

}

}

③.application.properties

server.port=8002

spring.application.name=provider-ticket

#注册服务的时候使用服务的ip地址

eureka.instance.prefer-ip-address=true

eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

(4).provider-ticket

[1].package

打包provider-ticket两次，一个端口为8001一次端口为8002

[2].启动provider

(5).consumer-user

[1]application.properties

server.port=8200

spring.application.name=consumer-user

#注册服务的时候使用服务的ip地址

eureka.instance.prefer-ip-address=true

eureka.client.service-url.defaultZone=http://localhost:8761/eureka/

[2].ConsumerUserApplication.java

package com.hosystem.consumeruser;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.cloud.client.discovery.EnableDiscoveryClient;

import org.springframework.cloud.client.loadbalancer.LoadBalanced;

import org.springframework.context.annotation.Bean;

import org.springframework.web.client.RestTemplate;

@EnableDiscoveryClient //开启发现功能

@SpringBootApplication

public class ConsumerUserApplication {

public static void main(String[] args) {

SpringApplication.run(ConsumerUserApplication.class, args);

}

@LoadBalanced  //使用负载均衡机制

   @Bean

public RestTemplate restTemplate(){

return new RestTemplate();

}

}

[3].UserController.java

package com.hosystem.consumeruser.controller;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RestController;

import org.springframework.web.client.RestTemplate;

@RestController

public class UserController {

@Autowired

RestTemplate restTemplate;

@GetMapping("/buy")

public String buyTicket(String name){

String s =  restTemplate.getForObject("http://PROVIDER-TICKET/ticket",String.class);

return name+"观看了"+s;

}

}

注意，观察加@LoadBalanced和不加@LoadBalanced的区别。加了@LoadBalanced的可以实现负载均衡。

参考文档：

https://github.com/alibaba/dubbo

https://hub.docker.com/_/zookeeper?tab=description

https://github.com/apache/dubbo/

https://mvnrepository.com/artifact/com.github.sgroschupf/zkclient

https://martinfowler.com/articles/microservices.html