使用Canal实现MySQL主从同步

说明：本文介绍如何使用Canal实现MySQL主从同步的效果，关于Canal入门使用参考：Canal入门使用

启动Canal

首先，设置Canal服务器里，目标节点（即监测的MySQL节点）的配置，启动Canal服务；

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启动Canal服务器，Windows操作系统下，直接双击startup.bat文件即可；

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具体操作参考：Canal入门使用

创建项目

创建一个Spring Boot项目，pom.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.12</version>
        <relativePath/>
    </parent>

    <groupId>com.hezy</groupId>
    <artifactId>canal_demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <!--druid-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.8</version>
        </dependency>

        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>

        <!--mysql驱动-->
        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>

        <!--canal客户端-->
        <dependency>
            <groupId>top.javatool</groupId>
            <artifactId>canal-spring-boot-starter</artifactId>
            <version>1.2.1-RELEASE</version>
        </dependency>
    </dependencies>

</project>

application.yml文件如下，这里的数据库配置写从节点的，且账户应该有数据读写权限；

server:
  port: 8080

# 1.数据源的配置
spring:
  # 数据库配置
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://从节点MySQLIP:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: 123456

# 2.mybatis配置
mybatis:
  configuration:
    # 显示SQL日志配置
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
    # 驼峰命名配置
    map-underscore-to-camel-case: true

# 3.canal配置
canal:
  # canal服务端的ip
  server: 127.0.0.1:11111
  destination: example

实体类对象

import lombok.Data;

import java.io.Serializable;

@Data
public class User implements Serializable {

    private String id;

    private String username;

    private String password;
}

canal处理类

import com.hezy.mapper.UserMapper;
import com.hezy.pojo.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import top.javatool.canal.client.annotation.CanalTable;
import top.javatool.canal.client.handler.EntryHandler;

@Component
@CanalTable("i_user")
public class UserHandler implements EntryHandler<User> {

    @Autowired
    private UserMapper userMapper;

    @Override
    public void insert(User user) {
        System.out.println("新增用户：" + user);
        userMapper.insertUser(user);
    }

    @Override
    public void update(User before, User after) {
        System.out.println("更新用户：" + before + " -> " + after);
        userMapper.updateUserById(after);
    }

    @Override
    public void delete(User user) {
        System.out.println("删除用户：" + user);
        userMapper.deleteUserById(user.getId());
    }
}

对应写三个针对User表（User实体类对应的表，即i_user表）操作的Mapper方法；

import com.hezy.pojo.User;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Update;

@Mapper
public interface UserMapper {


    @Insert("insert into i_user values (#{id}, #{username}, #{password})")
    void insertUser(User uesr);

    @Delete("delete from i_user where id = #{id}")
    void deleteUserById(String id);

    @Update("update i_user set username=#{username}, password=#{password} where id=#{id}")
    void updateUserById(User user);

}