Canal是阿里巴巴开源的一款数据库日志增量解析组件，通过Canal来解析数据库的日志信息，来检测数据库中表结构和数据的变化，从而更新Solr索引库。使用Canal可以做到业务代码完全解耦，API完全解耦，可以做到准实时。

1.实例 Canal实现MySQL与Redis数据同步。实现步骤如下：

1).修改my.ini添加binlog支持

#开启bInlog
log-bin=mysql-bin
#给mysql服务指定一个唯一的ID
server-id=1
#以数据的方式写binlog日志:statement是记录SQL,row是记录数据
binlog-format=ROW
#同步的数据库名
#binlog-do-db=canaldb
#忽略的表
binlog-ignore-db=mysql
#启动mysql时不启动grant-tables授权表
#skip-grant-tables

2).在MySQL中添加canal账号。

create user 'canal'@'%' IDENTIFIED WITH mysql_native_password BY 'canal';

grant SELECT, REPLICATION SLAVE, REPLICATION CLIENT on *.* to 'canal'@'%';

FLUSH PRIVILEGES;

#对于MySQL8以上版本，需要执行以下脚本。
select host,user,plugin from mysql.user ;

ALTER USER 'canal'@'%' IDENTIFIED WITH mysql_native_password BY 'canal';
FLUSH PRIVILEGES;

3).下载canal server.

去canal 官网下载canal server。

https://github.com/alibaba/canal/releases

4).修改canal server相关配置文档。

修改 canal.deployer-1.1.6/conf/example/instance.properties

#################################################
## mysql serverId , v1.0.26+ will autoGen
#canal.instance.mysql.slaveId=0

# enable gtid use true/false
canal.instance.gtidon=false

# position info
canal.instance.master.address=127.0.0.1:3306
canal.instance.master.journal.name=
canal.instance.master.position=
canal.instance.master.timestamp=
canal.instance.master.gtid=

# rds oss binlog
canal.instance.rds.accesskey=
canal.instance.rds.secretkey=
canal.instance.rds.instanceId=

# table meta tsdb info
canal.instance.tsdb.enable=true
#canal.instance.tsdb.url=jdbc:mysql://127.0.0.1:3306/canal_tsdb
#canal.instance.tsdb.dbUsername=root
#canal.instance.tsdb.dbPassword=root

#canal.instance.standby.address =
#canal.instance.standby.journal.name =
#canal.instance.standby.position =
#canal.instance.standby.timestamp =
#canal.instance.standby.gtid=

# username/password
canal.instance.dbUsername=canal
canal.instance.dbPassword=canal
canal.instance.connectionCharset = UTF-8
# enable druid Decrypt database password
canal.instance.enableDruid=false
#canal.instance.pwdPublicKey=MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBALK4BUxdDltRRE5/zXpVEVPUgunvscYFtEip3pmLlhrWpacX7y7GCMo2/JM6LeHmiiNdH1FWgGCpUfircSwlWKUCAwEAAQ==

# table regex
canal.instance.filter.regex=.*\\..*
# canal.instance.filter.regex=springboot.users
# table black regex
canal.instance.filter.black.regex=mysql\\.slave_.*
# table field filter(format: schema1.tableName1:field1/field2,schema2.tableName2:field1/field2)
#canal.instance.filter.field=test1.t_product:id/subject/keywords,test2.t_company:id/name/contact/ch
# table field black filter(format: schema1.tableName1:field1/field2,schema2.tableName2:field1/field2)
#canal.instance.filter.black.field=test1.t_product:subject/product_image,test2.t_company:id/name/contact/ch

# mq config
canal.mq.topic=example
# dynamic topic route by schema or table regex
#canal.mq.dynamicTopic=mytest1.user,topic2:mytest2\\..*,.*\\..*
canal.mq.partition=0
# hash partition config
#canal.mq.enableDynamicQueuePartition=false
#canal.mq.partitionsNum=3
#canal.mq.dynamicTopicPartitionNum=test.*:4,mycanal:6
#canal.mq.partitionHash=test.table:id^name,.*\\..*
#################################################
canal.instance.parser.parallel=false

修改 canal.deployer-1.1.6/conf/canal.properties

#################################################
#########       common argument     #############
#################################################
# tcp bind ip
canal.ip = 127.0.0.1
# register ip to zookeeper
canal.register.ip =
canal.port = 11111
canal.metrics.pull.port = 11112
# canal instance user/passwd
# canal.user = canal
# canal.passwd = E3619321C1A937C46A0D8BD1DAC39F93B27D4458

# canal admin config
#canal.admin.manager = 127.0.0.1:8089
canal.admin.port = 11110
canal.admin.user = admin
canal.admin.passwd = 4ACFE3202A5FF5CF467898FC58AAB1D615029441
# admin auto register
#canal.admin.register.auto = true
#canal.admin.register.cluster =
#canal.admin.register.name =

canal.zkServers =
# flush data to zk
canal.zookeeper.flush.period = 1000
canal.withoutNetty = false
# tcp, kafka, rocketMQ, rabbitMQ, pulsarMQ
canal.serverMode = tcp
# flush meta cursor/parse position to file
canal.file.data.dir = ${canal.conf.dir}
canal.file.flush.period = 1000
## memory store RingBuffer size, should be Math.pow(2,n)
canal.instance.memory.buffer.size = 16384
## memory store RingBuffer used memory unit size , default 1kb
canal.instance.memory.buffer.memunit = 1024 
## meory store gets mode used MEMSIZE or ITEMSIZE
canal.instance.memory.batch.mode = MEMSIZE
canal.instance.memory.rawEntry = true

## detecing config
canal.instance.detecting.enable = false
#canal.instance.detecting.sql = insert into retl.xdual values(1,now()) on duplicate key update x=now()
canal.instance.detecting.sql = select 1
canal.instance.detecting.interval.time = 3
canal.instance.detecting.retry.threshold = 3
canal.instance.detecting.heartbeatHaEnable = false

# support maximum transaction size, more than the size of the transaction will be cut into multiple transactions delivery
canal.instance.transaction.size =  1024
# mysql fallback connected to new master should fallback times
canal.instance.fallbackIntervalInSeconds = 60

# network config
canal.instance.network.receiveBufferSize = 16384
canal.instance.network.sendBufferSize = 16384
canal.instance.network.soTimeout = 30

# binlog filter config
canal.instance.filter.druid.ddl = true
canal.instance.filter.query.dcl = false
canal.instance.filter.query.dml = false
canal.instance.filter.query.ddl = false
canal.instance.filter.table.error = false
canal.instance.filter.rows = false
canal.instance.filter.transaction.entry = false
canal.instance.filter.dml.insert = false
canal.instance.filter.dml.update = false
canal.instance.filter.dml.delete = false

# binlog format/image check
canal.instance.binlog.format = ROW,STATEMENT,MIXED 
canal.instance.binlog.image = FULL,MINIMAL,NOBLOB

# binlog ddl isolation
canal.instance.get.ddl.isolation = false

# parallel parser config
canal.instance.parser.parallel = true
## concurrent thread number, default 60% available processors, suggest not to exceed Runtime.getRuntime().availableProcessors()
#canal.instance.parser.parallelThreadSize = 16
## disruptor ringbuffer size, must be power of 2
canal.instance.parser.parallelBufferSize = 256

# table meta tsdb info
canal.instance.tsdb.enable = true
canal.instance.tsdb.dir = ${canal.file.data.dir:../conf}/${canal.instance.destination:}
canal.instance.tsdb.url = jdbc:h2:${canal.instance.tsdb.dir}/h2;CACHE_SIZE=1000;MODE=MYSQL;
canal.instance.tsdb.dbUsername = canal
canal.instance.tsdb.dbPassword = canal
# dump snapshot interval, default 24 hour
canal.instance.tsdb.snapshot.interval = 24
# purge snapshot expire , default 360 hour(15 days)
canal.instance.tsdb.snapshot.expire = 360

#################################################
#########       destinations        #############
#################################################
canal.destinations = example
# conf root dir
canal.conf.dir = ../conf
# auto scan instance dir add/remove and start/stop instance
canal.auto.scan = true
canal.auto.scan.interval = 5
# set this value to 'true' means that when binlog pos not found, skip to latest.
# WARN: pls keep 'false' in production env, or if you know what you want.
canal.auto.reset.latest.pos.mode = false

canal.instance.tsdb.spring.xml = classpath:spring/tsdb/h2-tsdb.xml
#canal.instance.tsdb.spring.xml = classpath:spring/tsdb/mysql-tsdb.xml

canal.instance.global.mode = spring
canal.instance.global.lazy = false
canal.instance.global.manager.address = ${canal.admin.manager}
#canal.instance.global.spring.xml = classpath:spring/memory-instance.xml
canal.instance.global.spring.xml = classpath:spring/file-instance.xml
#canal.instance.global.spring.xml = classpath:spring/default-instance.xml

##################################################
#########         MQ Properties      #############
##################################################
# aliyun ak/sk , support rds/mq
canal.aliyun.accessKey =
canal.aliyun.secretKey =
canal.aliyun.uid=

canal.mq.flatMessage = true
canal.mq.canalBatchSize = 50
canal.mq.canalGetTimeout = 100
# Set this value to "cloud", if you want open message trace feature in aliyun.
canal.mq.accessChannel = local

canal.mq.database.hash = true
canal.mq.send.thread.size = 30
canal.mq.build.thread.size = 8

##################################################
#########            Kafka           #############
##################################################
kafka.bootstrap.servers = 127.0.0.1:9092
kafka.acks = all
kafka.compression.type = none
kafka.batch.size = 16384
kafka.linger.ms = 1
kafka.max.request.size = 1048576
kafka.buffer.memory = 33554432
kafka.max.in.flight.requests.per.connection = 1
kafka.retries = 0

kafka.kerberos.enable = false
kafka.kerberos.krb5.file = "../conf/kerberos/krb5.conf"
kafka.kerberos.jaas.file = "../conf/kerberos/jaas.conf"

##################################################
#########           RocketMQ         #############
##################################################
rocketmq.producer.group = test
rocketmq.enable.message.trace = false
rocketmq.customized.trace.topic =
rocketmq.namespace =
rocketmq.namesrv.addr = 127.0.0.1:9876
rocketmq.retry.times.when.send.failed = 0
rocketmq.vip.channel.enabled = false
rocketmq.tag = 

##################################################
#########           RabbitMQ         #############
##################################################
rabbitmq.host =
rabbitmq.virtual.host =
rabbitmq.exchange =
rabbitmq.username =
rabbitmq.password =
rabbitmq.deliveryMode =


##################################################
#########             Pulsar         #############
##################################################
pulsarmq.serverUrl =
pulsarmq.roleToken =
pulsarmq.topicTenantPrefix =

5).canal server 启动测试。

执行 - canal.deployer-1.1.6/bin/startup.bat (Windows) - canal.deployer-1.1.6/bin/startup.sh (Linux)

观察 canal.deployer-1.1.6/log/canal/canal.log 和 canal.deployer-1.1.6/log/example/example.log 是否有错误日志记录，如果没有任何报错信息，说明canal server启动成功！

6).pom.xml添加依赖

<properties>
     <java.version>1.8</java.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
     <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
     <!--Springboot高版本和starter-canal版本不兼容，必须降到2.3.7.RELEASE-->
     <spring-boot.version>2.3.7.RELEASE</spring-boot.version>     
</properties>


<dependencies>
   ...
   <!--注意这个依赖你从maven无法下载-->
  <dependency>
     <groupId>com.xpand</groupId>
     <artifactId>starter-canal</artifactId>
     <version>0.0.1-SNAPSHOT</version>
  </dependency>
</dependencies>

解决：starter-canal 无法maven导入，大家可以执行以下命令，把jar包安装到本地仓库即可。

mvn install:install-file "-DgroupId=com.xpand" "-DartifactId=starter-canal" "-Dversion=0.0.1-SNAPSHOT" "-Dpackaging=jar" "-Dfile=starter-canal-0.0.1-SNAPSHOT.jar"

7).配置application.yml

canal:
  server: 127.0.0.1:11111 #canal的地址
  destination: example #默认的数据同步的目的地
  client:
    instances:
      example:
        host: 127.0.0.1
        port: 11111
#数据源配置
spring:
  # redis配置
  redis:
    # Redis数据库索引（默认为0）
    database: 0
    # Redis服务器地址
    host: localhost
    # Redis服务器连接端口
    port: 6379
    # Redis服务器连接密码（默认为空）
    password: helloworld2021
    # 连接超时时间（毫秒）
    timeout: 1000ms
    lettuce:
      pool:
        # 连接池最大连接数
        max-active: 200
        # 连接池最大阻塞等待时间（使用负值表示没有限制）
        max-wait: -1ms
        # 连接池中的最大空闲连接
        max-idle: 10
        # 连接池中的最小空闲连接
        min-idle: 0
  cache:
    type: redis

8).启动类添加注解

@SpringBootApplication
@MapperScan(basePackages = {"com.simoniu.springboot.mapper"})
@EnableCaching  //开启缓存支持
@EnableCanalClient //开启CanalClient支持
public class FirstdemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(FirstdemoApplication.class, args);
    }
}

9).在listener包下配置canal监听器

import com.alibaba.otter.canal.protocol.CanalEntry;
import com.hqyj.springboot.util.RedisUtil;
import com.xpand.starter.canal.annotation.*;
import javax.annotation.Resource;

@CanalEventListener
public class CanalDataEventListener {

    @Resource
    private RedisUtil redisUtil;

    /**
     * @Description: 增加数据监听
     * @Author: yangjj_tc
     * @Date: 2022/11/11 15:16
     */
    @InsertListenPoint
    public void onEventInsert(CanalEntry.EventType eventType, CanalEntry.RowData rowData) {
        rowData.getAfterColumnsList()
                .forEach((c) -> System.out.println("By--Annotation: " + c.getName() + " ::   " + c.getValue()));
    }

    /**
     * @Description: 修改数据监听
     * @Author: yangjj_tc
     * @Date: 2022/11/11 15:17
     */
    @UpdateListenPoint
    public void onEventUpdate(CanalEntry.RowData rowData) {
        System.out.println("UpdateListenPoint");
        rowData.getAfterColumnsList()
                .forEach((c) -> System.out.println("By--Annotation: " + c.getName() + " ::   " + c.getValue()));
    }

    /**
     * @Description: 删除数据监听
     * @Author: yangjj_tc
     * @Date: 2022/11/11 15:17
     */
    @DeleteListenPoint
    public void onEventDelete(CanalEntry.EventType eventType) {
        System.out.println("DeleteListenPoint");
    }

    /**
     * @Description: 自定义数据监听
     * @Author: yangjj_tc
     * @Date: 2022/11/11 15:18
     */
    @ListenPoint(destination = "example", schema = "springboot", table = {"users"},
            eventType = CanalEntry.EventType.UPDATE)
    public void onEventCustomUpdate(CanalEntry.EventType eventType, CanalEntry.RowData rowData) {
        System.err.println("DeleteListenPoint");
        rowData.getAfterColumnsList()
                .forEach((c) -> System.out.println("By--Annotation: " + c.getName() + " ::   " + c.getValue()));
    }

    @ListenPoint(destination = "example", schema = "springboot", // 所要监听的数据库名
            table = {"users"}, // 所要监听的数据库表名
            eventType = {CanalEntry.EventType.UPDATE, CanalEntry.EventType.INSERT, CanalEntry.EventType.DELETE})
    public void onEventCustomUpdateForTbUser(CanalEntry.EventType eventType, CanalEntry.RowData rowData) {
        //getChangeValue(eventType, rowData);
        System.out.println("检测到users表触发了插入，更新或者删除操作.....");
        rowData.getAfterColumnsList()
                .forEach((c) -> System.out.println("By--Annotation: " + c.getName() + " ::   " + c.getValue()));
        System.out.println("-----------执行删除redis缓存--------");
        redisUtil.removeByPrex("usersCacheList");
    }

    public static void getChangeValue(CanalEntry.EventType eventType, CanalEntry.RowData rowData) {
        if (eventType == CanalEntry.EventType.DELETE) {
            rowData.getBeforeColumnsList().forEach(column -> {
                // 获取删除前的数据
                System.out.println(column.getName() + " == " + column.getValue());
            });
        } else {
            rowData.getBeforeColumnsList().forEach(column -> {
                // 打印改变前的字段名和值
                System.out.println(column.getName() + " == " + column.getValue());
            });
            rowData.getAfterColumnsList().forEach(column -> {
                // 打印改变后的字段名和值
                System.out.println(column.getName() + " == " + column.getValue());
            });
        }
    }
}

10).启动项目测试数据是否同步

尝试修改 users表里的一条记录。

检测到users表触发了插入，更新或者删除操作.....
By--Annotation: uid ::   32
By--Annotation: username ::   王老二
By--Annotation: password ::   123456
By--Annotation: gender ::   男
By--Annotation: birthday ::   2023-05-01
By--Annotation: address ::   
By--Annotation: create_time ::   2023-05-11 14:21:31
By--Annotation: flag ::   0
By--Annotation: modify_time ::   2023-05-11 14:21:31
By--Annotation: version ::   1
By--Annotation: mobile ::   
-----------执行删除redis缓存--------