MySQL - Canal數據同步

Canal是阿里巴巴旗下的一款開源項目，純Java開發。基於數據庫增量日誌解析，提供增量數據訂閱&消費，目前主要支持了MySQL。
原理和應用場景參考：Canal——原理架構及應用場景

Canal環境搭建

Canal的原理是基於mysql binlog技術，所以這裏一定需要開啓mysql的binlog寫入功能

1、檢查binlog功能是否有開啓

show variables like 'log_bin';

如果value爲OFF則表示未開啓。

2、開啓binlog功能

1、修改 mysql 的配置文件 my.cnf

vi /etc/my.cnf

追加以下內容

# binlog文件名
log-bin=mysql-bin
# 選擇row模式
binlog_format=ROW
# mysql實例id,不能和canal的slaveId重複
server_id=1

2、重啓MySQL服務

systemctl restart mysqld.service

3、查看是否開啓成功

3、下載安裝Canal服務

下載地址：Canal的GitHub地址

1、我這裏將它放在/usr/local/canal目錄下，將其解壓

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

修改本機數據庫的address

修改數據庫信息，建議創建一個新用戶並授權，或是給root用戶授權。

修改表的匹配規則，這表示guli_edu數據庫中的member表

表的匹配規則

mysql 數據解析關注的表，Perl正則表達式.
多個正則之間以逗號(,)分隔，轉義符需要雙斜槓(\\) 
常見例子：
1.所有表：.*   or  .*\\..*
2.canal schema下所有表： canal\\..*
3.canal下的以canal打頭的表：canal\\.canal.*
4.canal schema下的一張表：canal.test1
5.多個規則組合使用：canal\\..*,mysql.test1,mysql.test2 (逗號分隔)
注意：此過濾條件只針對row模式的數據有效(ps. mixed/statement因爲不解析sql，所以無法準確提取tableName進行過濾)

4、啓動Canal

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

SpringBoot代碼

1、引入相關依賴

<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>
<!-- 主要是這個依賴 -->
<dependency>
	<groupId>com.alibaba.otter</groupId>
	<artifactId>canal.client</artifactId>
</dependency>

2、書寫配置文件

# 服務端口
server.port=10000
# 服務名
spring.application.name=canal-client

# 環境設置：dev、test、prod
spring.profiles.active=dev

# mysql數據庫連接
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、編寫canal客戶端類

@Component
public class CanalClient {

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

    @Resource
    private DataSource dataSource;

    /**
     * canal入庫方法
     * 注意修改遠程MySQL數據庫的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) {
                    // 嘗試從master那邊拉去數據batchSize條記錄，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);

                    // 當隊列裏面堆積的sql大於一定數值的時候就模擬執行
                    if (SQL_QUEUE.size() >= 1) {
                        executeQueueSql();
                    }
                }
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (InvalidProtocolBufferException e) {
                e.printStackTrace();
            }
        } finally {
            connector.disconnect();
        }
    }

    /**
     * 模擬執行隊列裏面的sql語句
     */
    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());
        }
    }

    /**
     * 數據處理
     *
     * @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);
                }
            }
        }
    }

    /**
     * 保存更新語句
     *
     * @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()) {
                        //暫時只支持單一主鍵
                        sql.append(column.getName() + "=" + column.getValue());
                        break;
                    }
                }
                SQL_QUEUE.add(sql.toString());
            }
        } catch (InvalidProtocolBufferException e) {
            e.printStackTrace();
        }
    }

    /**
     * 保存刪除語句
     *
     * @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()) {
                        //暫時只支持單一主鍵
                        sql.append(column.getName() + "=" + column.getValue());
                        break;
                    }
                }
                SQL_QUEUE.add(sql.toString());
            }
        } catch (InvalidProtocolBufferException e) {
            e.printStackTrace();
        }
    }

    /**
     * 保存插入語句
     *
     * @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();
        }
    }

    /**
     * 入庫
     * @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、創建啓動類

@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 {
        //項目啓動，執行canal客戶端監聽
        canalClient.run();
    }
}

6、在遠程MySQL新增、修改、刪除測試即可