基于Canal的数据同步

一、 系统结构

该数据同步系统由Spring Boot和Canal共同组成。
Spring Boot 是一个流行的 Java Web 框架，而 Canal 则是阿里巴巴开源的 MySQL 数据库的数据变更监听框架。结合 Spring Boot 和 Canal，可以实现 MySQL 数据库的实时数据同步到其他系统中。

1. canal.deployer-1.1.7-SNAPSHOT.tar.gz为Canal软件压缩包，需要安装在服务器上，并根据下文进行配置文件的修改。
2. CanalClient.rar为用Spring Boot框架编写的数据库监听同步项目

二、. Canal配置

在解压Canal文件夹后，需要配置两个文件。
在配置Canal前，需要确保Mysql的Binlog已经开启，并且模式为ROW，找到当前binlog的文件名和position。

1） 配置文件路径：canal/conf/canal.properties

2） 配置文件路径：

canal/conf/example/instance.properties

三、 Spring Boot配置

1. 项目结构

2. Canal账号密码配置

进入到Config下的CanalClient类文件。

注意密码是通过MD5加密的，图中这这段字符应替换为canal。

3. 目标数据库配置

在yml中配置数据同步目标数据库即可

源代码:

package com.canal.canalclient.config;import com.alibaba.otter.canal.client.CanalConnector;
import com.alibaba.otter.canal.client.CanalConnectors;
import com.alibaba.otter.canal.protocol.CanalEntry;
import com.alibaba.otter.canal.protocol.CanalEntry.Column;
import com.alibaba.otter.canal.protocol.CanalEntry.EntryType;
import com.alibaba.otter.canal.protocol.CanalEntry.EventType;
import com.alibaba.otter.canal.protocol.CanalEntry.RowChange;
import com.alibaba.otter.canal.protocol.Message;
import com.google.protobuf.InvalidProtocolBufferException;
import org.springframework.jdbc.core.JdbcTemplate;import java.net.InetSocketAddress;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
/*** @Auther: fzl* @Date: 2020/4/20 01:21* @Description:*/
public class CanalClient {private static Queue SQL_QUEUE = new ConcurrentLinkedQueue<>();public static void startCanal() {//获取canalServer连接：本机地址,端口号CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("IP地址", "端口号"), "example", "canal", "canal");int batchSize = 1000;try {//连接canalServerconnector.connect();//订阅Desctinstionconnector.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//轮询拉取数据   上面的whereMessage message = connector.getWithoutAck(batchSize);long batchId = message.getId();int size = message.getEntries().size();if (batchId == -1 || size == 0) {//睡眠Thread.sleep(1000);} else {dataHandle(message.getEntries());}connector.ack(batchId);System.out.println("aa"+size);//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() >= 10) {executeQueueSql();}}} catch (InterruptedException e) {e.printStackTrace();} catch (InvalidProtocolBufferException e) {e.printStackTrace();}} finally {connector.disconnect();}}public static JdbcTemplate jdbcTemplate;/*** 模拟执行队列里面的sql语句*/public static void executeQueueSql() {int size = SQL_QUEUE.size();for (int i = 0; i < size; i++) {String sql = SQL_QUEUE.poll();jdbcTemplate.execute(sql);System.out.println("[sql]----> " + sql);}}/*** 数据处理** @param entrys*/private static void dataHandle(List entrys) throws InvalidProtocolBufferException {for (CanalEntry.Entry entry : entrys) {if (EntryType.ROWDATA == entry.getEntryType()) {RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());CanalEntry.EventType eventType = rowChange.getEventType();if (eventType == EventType.DELETE) {saveDeleteSql(entry);} else if (eventType == EventType.UPDATE) {saveUpdateSql(entry);} else if (eventType == CanalEntry.EventType.INSERT) {saveInsertSql(entry);}}}}/*** 保存更新语句** @param entry*/private static void saveUpdateSql(CanalEntry.Entry entry) {try {RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());List rowDatasList = rowChange.getRowDatasList();for (CanalEntry.RowData rowData : rowDatasList) {List newColumnList = rowData.getAfterColumnsList();StringBuffer sql = new StringBuffer("update " + entry.getHeader().getSchemaName() + "." + 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 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 static void saveDeleteSql(CanalEntry.Entry entry) {try {RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());List rowDatasList = rowChange.getRowDatasList();for (CanalEntry.RowData rowData : rowDatasList) {List columnList = rowData.getBeforeColumnsList();StringBuffer sql = new StringBuffer("delete from " + entry.getHeader().getSchemaName() + "." + 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 static void saveInsertSql(CanalEntry.Entry entry) {try {RowChange rowChange = RowChange.parseFrom(entry.getStoreValue());List rowDatasList = rowChange.getRowDatasList();for (CanalEntry.RowData rowData : rowDatasList) {List columnList = rowData.getAfterColumnsList();StringBuffer sql = new StringBuffer("insert into " + entry.getHeader().getSchemaName() + "." + 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();}}
}

package com.canal.canalclient;import com.canal.canalclient.config.CanalClient;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.stereotype.Component;@Component
@Slf4j
public class StartedFunction implements ApplicationRunner {@Autowired@Qualifier("test_master_energy") //有多个数据源的，需要名称区分private static JdbcTemplate jdbcTemplate;@Overridepublic void run(ApplicationArguments args)  throws Exception{log.info("开始监听同步数据库");CanalClient.jdbcTemplate = jdbcTemplate;CanalClient.startCanal();}
}

4.0.0org.springframework.bootspring-boot-starter-parent3.0.3 com.canalCanalClient0.0.1-SNAPSHOTCanalClientCanalClient19org.springframework.bootspring-boot-starterorg.springframework.bootspring-boot-starter-weborg.springframework.bootspring-boot-starter-testtestcom.alibaba.ottercanal.client1.1.4com.alibabadruid-spring-boot-starter1.2.9mysqlmysql-connector-java8.0.32org.projectlomboklombokorg.apache.maven.pluginsmaven-surefire-plugin2.12.4trueorg.springframework.bootspring-boot-maven-pluginsrc/main/resourcessrc/main/java**/*.xml