MySQL - Canal数据同步

Canal是阿里巴巴旗下的一款开源项目，纯Java开发。基于数据库增量日志解析，提供增量数据订阅&消费，目前主要支持了MySQL。
原理和应用场景参考：Canal——原理架构及应用场景

Canal环境搭建

Canal的原理是基于mysql binlog技术，所以这里一定需要开启mysql的binlog写入功能

1、检查binlog功能是否有开启

show variables like 'log_bin';

如果value为OFF则表示未开启。

2、开启binlog功能

1、修改 mysql 的配置文件 my.cnf

vi /etc/my.cnf

追加以下内容

# binlog文件名
log-bin=mysql-bin
# 选择row模式
binlog_format=ROW
# mysql实例id,不能和canal的slaveId重复
server_id=1

2、重启MySQL服务

systemctl restart mysqld.service

3、查看是否开启成功

3、下载安装Canal服务

下载地址：Canal的GitHub地址

1、我这里将它放在/usr/local/canal目录下，将其解压

cd /usr/local/canal
tar zxvf canal.deployer-1.1.4.tar.gz

2、修改instance.properties配置文件

cd /usr/local/canal/conf/example
vi instance.properties

修改本机数据库的address

修改数据库信息，建议创建一个新用户并授权，或是给root用户授权。

修改表的匹配规则，这表示guli_edu数据库中的member表

表的匹配规则

mysql 数据解析关注的表，Perl正则表达式.
多个正则之间以逗号(,)分隔，转义符需要双斜杠(\\) 
常见例子：
1.所有表：.*   or  .*\\..*
2.canal schema下所有表： canal\\..*
3.canal下的以canal打头的表：canal\\.canal.*
4.canal schema下的一张表：canal.test1
5.多个规则组合使用：canal\\..*,mysql.test1,mysql.test2 (逗号分隔)
注意：此过滤条件只针对row模式的数据有效(ps. mixed/statement因为不解析sql，所以无法准确提取tableName进行过滤)

4、启动Canal

cd /usr/local/canal/bin
./startup.sh

SpringBoot代码

1、引入相关依赖

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

<!--mysql-->
<dependency>
	<groupId>mysql</groupId>
	<artifactId>mysql-connector-java</artifactId>
</dependency>

<dependency>
	<groupId>commons-dbutils</groupId>
	<artifactId>commons-dbutils</artifactId>
</dependency>

<dependency>
	<groupId>org.springframework.boot</groupId>
	<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<!-- 主要是这个依赖 -->
<dependency>
	<groupId>com.alibaba.otter</groupId>
	<artifactId>canal.client</artifactId>
</dependency>

2、书写配置文件

# 服务端口
server.port=10000
# 服务名
spring.application.name=canal-client

# 环境设置：dev、test、prod
spring.profiles.active=dev

# mysql数据库连接
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/guli_edu?serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=123456

3、编写canal客户端类

@Component
public class CanalClient {

    // sql队列
    private Queue<String> SQL_QUEUE = new ConcurrentLinkedQueue<>();

    @Resource
    private DataSource dataSource;

    /**
     * canal入库方法
     * 注意修改远程MySQL数据库的ip地址
     */
    public void run() {

        CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("122.51.112.192",
                11111), "example", "", "");
        int batchSize = 1000;
        try {
            connector.connect();
            connector.subscribe(".*\\..*");
            connector.rollback();
            try {
                while (true) {
                    // 尝试从master那边拉去数据batchSize条记录，有多少取多少
                    Message message = connector.getWithoutAck(batchSize);
                    long batchId = message.getId();
                    int size = message.getEntries().size();
                    if (batchId == -1 || size == 0) {
                        Thread.sleep(1000);
                    } else {
                        dataHandle(message.getEntries());
                    }
                    connector.ack(batchId);

                    // 当队列里面堆积的sql大于一定数值的时候就模拟执行
                    if (SQL_QUEUE.size() >= 1) {
                        executeQueueSql();
                    }
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (InvalidProtocolBufferException e) {
                e.printStackTrace();
            }
        } finally {
            connector.disconnect();
        }
    }

    /**
     * 模拟执行队列里面的sql语句
     */
    public void executeQueueSql() {
        int size = SQL_QUEUE.size();
        for (int i = 0; i < size; i++) {
            String sql = SQL_QUEUE.poll();
            System.out.println("[sql]----> " + sql);

            this.execute(sql.toString());
        }
    }

    /**
     * 数据处理
     *
     * @param entrys
     */
    private void dataHandle(List<Entry> entrys) throws InvalidProtocolBufferException {
        for (Entry entry : entrys) {
            if (EntryType.ROWDATA == entry.getEntryType()) {
                RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());
                EventType eventType = rowChange.getEventType();
                if (eventType == EventType.DELETE) {
                    saveDeleteSql(entry);
                } else if (eventType == EventType.UPDATE) {
                    saveUpdateSql(entry);
                } else if (eventType == EventType.INSERT) {
                    saveInsertSql(entry);
                }
            }
        }
    }

    /**
     * 保存更新语句
     *
     * @param entry
     */
    private void saveUpdateSql(Entry entry) {
        try {
            RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());
            List<RowData> rowDatasList = rowChange.getRowDatasList();
            for (RowData rowData : rowDatasList) {
                List<Column> newColumnList = rowData.getAfterColumnsList();
                StringBuffer sql = new StringBuffer("update " + entry.getHeader().getTableName() + " set ");
                for (int i = 0; i < newColumnList.size(); i++) {
                    sql.append(" " + newColumnList.get(i).getName()
                            + " = '" + newColumnList.get(i).getValue() + "'");
                    if (i != newColumnList.size() - 1) {
                        sql.append(",");
                    }
                }
                sql.append(" where ");
                List<Column> oldColumnList = rowData.getBeforeColumnsList();
                for (Column column : oldColumnList) {
                    if (column.getIsKey()) {
                        //暂时只支持单一主键
                        sql.append(column.getName() + "=" + column.getValue());
                        break;
                    }
                }
                SQL_QUEUE.add(sql.toString());
            }
        } catch (InvalidProtocolBufferException e) {
            e.printStackTrace();
        }
    }

    /**
     * 保存删除语句
     *
     * @param entry
     */
    private void saveDeleteSql(Entry entry) {
        try {
            RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());
            List<RowData> rowDatasList = rowChange.getRowDatasList();
            for (RowData rowData : rowDatasList) {
                List<Column> columnList = rowData.getBeforeColumnsList();
                StringBuffer sql = new StringBuffer("delete from " + entry.getHeader().getTableName() + " where ");
                for (Column column : columnList) {
                    if (column.getIsKey()) {
                        //暂时只支持单一主键
                        sql.append(column.getName() + "=" + column.getValue());
                        break;
                    }
                }
                SQL_QUEUE.add(sql.toString());
            }
        } catch (InvalidProtocolBufferException e) {
            e.printStackTrace();
        }
    }

    /**
     * 保存插入语句
     *
     * @param entry
     */
    private void saveInsertSql(Entry entry) {
        try {
            RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());
            List<RowData> rowDatasList = rowChange.getRowDatasList();
            for (RowData rowData : rowDatasList) {
                List<Column> columnList = rowData.getAfterColumnsList();
                StringBuffer sql = new StringBuffer("insert into " + entry.getHeader().getTableName() + " (");
                for (int i = 0; i < columnList.size(); i++) {
                    sql.append(columnList.get(i).getName());
                    if (i != columnList.size() - 1) {
                        sql.append(",");
                    }
                }
                sql.append(") VALUES (");
                for (int i = 0; i < columnList.size(); i++) {
                    sql.append("'" + columnList.get(i).getValue() + "'");
                    if (i != columnList.size() - 1) {
                        sql.append(",");
                    }
                }
                sql.append(")");
                SQL_QUEUE.add(sql.toString());
            }
        } catch (InvalidProtocolBufferException e) {
            e.printStackTrace();
        }
    }

    /**
     * 入库
     * @param sql
     */
    public void execute(String sql) {
        Connection con = null;
        try {
            if(null == sql) return;
            con = dataSource.getConnection();
            QueryRunner qr = new QueryRunner();
            int row = qr.execute(con, sql);
            System.out.println("update: "+ row);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DbUtils.closeQuietly(con);
        }
    }
}

4、创建启动类

@SpringBootApplication
public class CanalApplication implements CommandLineRunner {
    @Resource
    private CanalClient canalClient;

    public static void main(String[] args) {
        SpringApplication.run(CanalApplication.class, args);
    }

    @Override
    public void run(String... strings) throws Exception {
        //项目启动，执行canal客户端监听
        canalClient.run();
    }
}

6、在远程MySQL新增、修改、删除测试即可