es与mysql之间的数据同步

常见的数据同步方案有三种：

方案一：同步调用（基本不会用，问题太多）

方案二：异步通知（一般会选择这种方案）

方案三：监听binlog

在此，只演示方案二：

1）引入依赖，改配置

在消费方和生产方，引入rabbitmq的依赖：

<!--amqp-->
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-amqp</artifactId>
</dependency>

 在消费方和生产方，修改application.yaml配置文件

spring:
  rabbitmq:
    host:192.168.177.132 
    port:5672
    username:itcast
    password:123321
    virtual-host:/

2）在消费方，声明队列交换机名称

package cn.itcast.hotel.constatnts;

    public class MqConstants {
    /**
     * 交换机
     */
    public final static String HOTEL_EXCHANGE = "hotel.topic";
    /**
     * 监听新增和修改的队列
     */
    public final static String HOTEL_INSERT_QUEUE = "hotel.insert.queue";
    /**
     * 监听删除的队列
     */
    public final static String HOTEL_DELETE_QUEUE = "hotel.delete.queue";
    /**
     * 新增或修改的RoutingKey
     */
    public final static String HOTEL_INSERT_KEY = "hotel.insert";
    /**
     * 删除的RoutingKey
     */
    public final static String HOTEL_DELETE_KEY = "hotel.delete";
}

3）在消费方，声明队列交换机

定义配置类，声明队列、交换机：

package cn.itcast.hotel.config;

import cn.itcast.hotel.constants.MqConstants;
import org.springframework.amqp.core.Binding;
import org.springframework.amqp.core.BindingBuilder;
import org.springframework.amqp.core.Queue;
import org.springframework.amqp.core.TopicExchange;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
public class MqConfig {

    //交换机
    @Bean
    public TopicExchange topicExchange(){
        return new TopicExchange(MqConstants.HOTEL_EXCHANGE, true, false);
    }

    //队列
    @Bean
    public Queue insertQueue(){
        return new Queue(MqConstants.HOTEL_INSERT_QUEUE, true);
    }

    //队列
    @Bean
    public Queue deleteQueue(){
        return new Queue(MqConstants.HOTEL_DELETE_QUEUE, true);
    }
    
    //绑定
    @Bean
    public Binding insertQueueBinding(){
        return BindingBuilder.bind(insertQueue()).to(topicExchange()).with(MqConstants.HOTEL_INSERT_KEY);
    }

    //绑定
    @Bean
    public Binding deleteQueueBinding(){
        return BindingBuilder.bind(deleteQueue()).to(topicExchange()).with(MqConstants.HOTEL_DELETE_KEY);
    }
}

4）在生产方，操作mysql的增、删、改业务中分别给MQ发送消息：

1.在conroller层，注入MQ对象

@Autowired
private RabbitTemplate rabbitTemplate;

2.在增、删、改业务中分别给MQ发送消息

5）当消费方（操作es侧），接收到MQ的消息：

• 新增消息：根据传递的hotel的id查询hotel信息，然后新增一条数据到索引库

• 删除消息：根据传递的hotel的id删除索引库中的一条数据

1.在消费方的service中添加新增、删除业务

void deleteById(Long id);

void insertById(Long id);

2.service的实现类，实现业务：

@Autowired
private RestHighLevelClient client;

@Override
public void deleteById(Long id) {
    try {
        // 1.准备Request
        DeleteRequest request = new DeleteRequest("hotel", id.toString());
        // 2.发送请求
        client.delete(request, RequestOptions.DEFAULT);
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}

@Override
public void insertById(Long id) {
    try {
        // 0.根据id查询酒店数据
        Hotel hotel = getById(id);
        // 转换为文档类型
        HotelDoc hotelDoc = new HotelDoc(hotel);

        // 1.准备Request对象
        IndexRequest request = new IndexRequest("hotel").id(hotel.getId().toString());
        // 2.准备Json文档
        request.source(JSON.toJSONString(hotelDoc), XContentType.JSON);
        // 3.发送请求
        client.index(request, RequestOptions.DEFAULT);
    } catch (IOException e) {
        throw new RuntimeException(e);
    }
}

3.编写监听器

package cn.itcast.hotel.mq;

import cn.itcast.hotel.constants.MqConstants;
import cn.itcast.hotel.service.IHotelService;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;

@Component
public class HotelListener {

    @Autowired
    private IHotelService hotelService;

    /**
     * 监听酒店新增或修改的业务
     * @param id 酒店id
     */
    @RabbitListener(queues = MqConstants.HOTEL_INSERT_QUEUE)
    public void listenHotelInsertOrUpdate(Long id){
        hotelService.insertById(id);
    }

    /**
     * 监听酒店删除的业务
     * @param id 酒店id
     */
    @RabbitListener(queues = MqConstants.HOTEL_DELETE_QUEUE)
    public void listenHotelDelete(Long id){
        hotelService.deleteById(id);
    }
}