一、开启同步数据库的binlog功能
（1）开启同步数据端的数据库服务（比如我的将一号虚拟机上的mysql数据库作为同步操作数据库）

systemctl start mysql.service
mysql -h192.168.137.100 -uroot -p123

（2）检查mysql的binlog功能是否开启（可见是OFF，关闭的）

MySQL [(none)]> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin       | OFF   |
+---------------+-------+

（3）开启binlog功能，修改my.cnf配置文件：vim /etc/my.cnf
在文件中添加如下内容后，重启mysql服务，在查看mysql的binlog功能。可见已经开启。

log-bin=mysql-bin
binlog_format=ROW
server_id=1

MySQL [(none)]> show variables like 'log_bin';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| log_bin       | ON    |
+---------------+-------+

二、安装canal工具
（1）下载地址：https://github.com/alibaba/canal/releases
（2）下载文件：canal.deployer-1.1.4.tar.gz
（3）文件传到 /usr/local/canal文件夹下，解压

tar zxvf canal.deployer-1.1.4.tar.gz 

（4）修改配置文件vi conf/example/instance.properties
修改如下内容为数据库连接：
canal.instance.master.address=192.168.137.100:3306
canal.instance.dbUsername=root
canal.instance.dbPassword=123
（5）启动canal数据同步工具 cd bin
[root@localhost bin]# ./startup.sh

三、测试项目准备
（1）新建项目，引入如下依赖

<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>
<dependency>
   <groupId>com.alibaba.otter</groupId>
   <artifactId>canal.client</artifactId>
</dependency>

（2）项目配置文件配置本地同步数据库

# 服务端口
server.port=1000
# 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://192.168.137.130:3306/TeachOnLine?useUnicode=true&useSSL=false&characterEncoding=utf8&serverTimezone=Asia/Shanghai
spring.datasource.username=root
spring.datasource.password=123

（3）创建如下启动类

@SpringBootApplication
public class CanalApplication implements CommandLineRunner {
    @Resource
    private CanalClient canalClient;
    // canalClient为数据库同步操作执行类 
    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();
    }
}

（4）创建CanalClient数据库同步操作执行类内容如下（记得保证192.168.137.100服务器的11111端口可通）

@Component
public class CanalClient {
    //sql队列
    private Queue<String> SQL_QUEUE = new ConcurrentLinkedQueue<>();
    @Resource
    private DataSource dataSource;

    /**
     * canal入库方法
     */
    public void run() {
        // 创建远程数据库连接对象
        CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("192.168.137.100",
                11111), "example", "", "");
        int batchSize = 1000;
        try {
            connector.connect();// 尝试连接
            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);// 语句最终执行！
            System.out.println("update: "+ row);
        } catch (SQLException e) {
            e.printStackTrace();
        } finally {
            DbUtils.closeQuietly(con);
        }
    }
}

四、测试
（1）启动类开启，在192.168.137.100(远程)数据库TeachOnLine的表members中插入数据
insert into members values(2,‘candy’,22);
（2）查看控制台打印信息

[sql]----> insert into members (id,username,age) VALUES ('2','candy','22')
update: 1

（3）在192.168.137.130(本地)数据库TeachOnLine的表members中出现相同数据。

注：在此例中本地数据库会同步远程数据库的变化，反过来修改本地数据库内容，远程数据库不会同步本地数据库的加粗样式变化