前言
使用canal之前要在linux中和windows中都安装数据库，linux安装数据库见博文
https://blog.csdn.net/weixin_45031570/article/details/125032004?csdn_share_tail=%7B%22type%22%3A%22blog%22%2C%22rType%22%3A%22article%22%2C%22rId%22%3A%22125032004%22%2C%22source%22%3A%22weixin_45031570%22%7D&ctrtid=tIbHy
一、mysql开启lob_bin
登录mysql
mysql -u root -p加上你的密码
或者
用图形工具打开（前提开放端口）
检查是否开启
show variables like 'log_bin 在linux数据库中检查是否开启 ，没有开启则继续向下浏览，否则进行（二、canal准备）
on就是开启
如果没有开启
1.查看官方文档：
https://github.com/alibaba/canal/wiki/QuickStart
2.修改配置 vim /etc/my.cnf
log-bin=mysql-bin #binlog文件名
binlog_format=ROW #选择row模式
server_id=1 #mysql实例id，不能和canal的slaveId重复
3.重启
systemctl restart mysql.service
4.检查是否开启
show variables like 'log_bin
二、canal准备
下载
wget https://github.com/alibaba/canal/releases/download/canal-1.0.17/canal.deployer-1.0.17.tar.gz
解压
tar -zxvf 文件名
修改配置文件
从 cd conf/example/找到instance.properties
修改ip和端口
canal.instance.master.address=192.168.182.130:3306 地址为linux地址
修改用户和密码
canal.instance.dbUsername=xxxx和 canal.instance.dbPassword=xxxx意思是可以远程连接的用户和密码
修改同步表，看你选择哪个
canal.instance.filter.regex=.*\\..* #所有表都同步
# table black regex
canal.instance.filter.black.regex=a数据库.b表 #某个表同步（a数据库.b表）
启动canal
打开目录 cd bin/ 启动命令./startup.sh
查看是否启动
ps -ef | grep canal
三、建工程
引入依赖
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<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>
配置yml
server:
port: 10001
spring:
application:
name: canal-client
profiles:
active: dev
datasource:
driver-class-name: com.mysql.cj.jdbc.Driver
url: jdbc:mysql://localhost:3306/xxxxx?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=Asia/Shanghai&allowPublicKeyRetrieval=true
username: xxx
password: xxx
写组件
固定写法（Java直接复制代码即可）
其中端口号是11111是固定的，ip改成linux中的，密码和账号改成之前**instance.properties**中配置的用户和密码
package com.merchen.client;
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.Message;
import com.google.protobuf.InvalidProtocolBufferException;
import org.apache.commons.dbutils.DbUtils;
import org.apache.commons.dbutils.QueryRunner;
import org.springframework.stereotype.Component;
import javax.annotation.Resource;
import javax.sql.DataSource;
import java.net.InetSocketAddress;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Iterator;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;
@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() {
CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress("192.168.182.130",
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);
}
}
}
写启动类
@SpringBootApplication
public class CanalMain10001 implements CommandLineRunner {
@Autowired
private CanalClient canalClient;
public static void main(String[] args) {
SpringApplication.run(CanalMain10001.class, args);
}
@Override
public void run(String... args) throws Exception {
//项目启动执行 canal客户监听
canalClient.run();
}
}
测试
当对linux中的mysql进行crud，本地端口的mysql就会进行同步操作
四、问题
java代码显示拒绝连接
查看linux中的canal日志
canal.log和example下的example.log日志，查看报错是否有 allowmemary 内存分配错误等字样是就是改虚拟机内存，增加值
启动不报错，更新表报错
可能是数据库版本不匹配
2边的数据库最好版本一样
