Canal之ClientSample

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ClientSample

直接使用canal.example工程

a. 首先启动Canal Server，可参见Canal快速开始
b.
1. 可以在eclipse里，直接打开com.alibaba.otter.canal.example.SimpleCanalClientTest，直接运行
2. 在工程的example目录下运行命令行：

mvn exec:java -Dexec.mainClass="com.alibaba.otter.canal.example.SimpleCanalClientTest"

下载example包: https://github.com/alibaba/canal/releases，解压缩后，直接运行sh startup.sh脚本
c. 触发数据变更
d. 在控制台或者logs中查看，可以看到如下信息：

================> binlog[mysql-bin.002579:508882822] , name[retl,xdual] , eventType : UPDATE , executeTime : 1368607728000 , delay : 4270ms-------> beforeID : 1    update=falseX : 2013-05-15 11:43:42    update=false-------> afterID : 1    update=falseX : 2013-05-15 16:48:48    update=true

从头创建工程

依赖配置：

<dependency>    <groupId>com.alibaba.otter</groupId>    <artifactId>canal.client</artifactId>    <version>1.0.12</version></dependency>

创建mvn标准工程：

mvn archetype:create -DgroupId=com.alibaba.otter -DartifactId=canal.sample

修改pom.xml，添加依赖
ClientSample代码

package com.alibaba.otter.canal.sample;import java.net.InetSocketAddress;import java.util.List;import com.alibaba.otter.canal.common.utils.AddressUtils;import com.alibaba.otter.canal.protocol.Message;import com.alibaba.otter.canal.protocol.CanalEntry.Column;import com.alibaba.otter.canal.protocol.CanalEntry.Entry;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.CanalEntry.RowData;public class SimpleCanalClientExample {    public static void main(String args[]) {        // 创建链接        CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress(AddressUtils.getHostIp(),                                                                                            11111), "example", "", "");        int batchSize = 1000;        int emptyCount = 0;        try {            connector.connect();            connector.subscribe(".*\\..*");            connector.rollback();            int totalEmtryCount = 120;            while (emptyCount < totalEmtryCount) {                Message message = connector.getWithoutAck(batchSize); // 获取指定数量的数据                long batchId = message.getId();                int size = message.getEntries().size();                if (batchId == -1 || size == 0) {                    emptyCount++;                    System.out.println("empty count : " + emptyCount);                    try {                        Thread.sleep(1000);                    } catch (InterruptedException e) {                    }                } else {                    emptyCount = 0;                    // System.out.printf("message[batchId=%s,size=%s] \n", batchId, size);                    printEntry(message.getEntries());                }                connector.ack(batchId); // 提交确认                // connector.rollback(batchId); // 处理失败, 回滚数据            }            System.out.println("empty too many times, exit");        } finally {            connector.disconnect();        }    }    private static void printEntry(List<Entry> entrys) {        for (Entry entry : entrys) {            if (entry.getEntryType() == EntryType.TRANSACTIONBEGIN || entry.getEntryType() == EntryType.TRANSACTIONEND) {                continue;            }            RowChange rowChage = null;            try {                rowChage = RowChange.parseFrom(entry.getStoreValue());            } catch (Exception e) {                throw new RuntimeException("ERROR ## parser of eromanga-event has an error , data:" + entry.toString(),                                           e);            }            EventType eventType = rowChage.getEventType();            System.out.println(String.format("================> binlog[%s:%s] , name[%s,%s] , eventType : %s",                                             entry.getHeader().getLogfileName(), entry.getHeader().getLogfileOffset(),                                             entry.getHeader().getSchemaName(), entry.getHeader().getTableName(),                                             eventType));            for (RowData rowData : rowChage.getRowDatasList()) {                if (eventType == EventType.DELETE) {                    printColumn(rowData.getBeforeColumnsList());                } else if (eventType == EventType.INSERT) {                    printColumn(rowData.getAfterColumnsList());                } else {                    System.out.println("-------> before");                    printColumn(rowData.getBeforeColumnsList());                    System.out.println("-------> after");                    printColumn(rowData.getAfterColumnsList());                }            }        }    }    private static void printColumn(List<Column> columns) {        for (Column column : columns) {            System.out.println(column.getName() + " : " + column.getValue() + "    update=" + column.getUpdated());        }    }}

运行Client
首先启动Canal Server，可参见Canal快速开始
启动Canal Client后，可以从控制台从看到类似消息：

empty count : 1empty count : 2empty count : 3empty count : 4

此时代表当前数据库无变更数据

触发数据库变更

mysql> use test;Database changedmysql> CREATE TABLE `xdual` (    ->   `ID` int(11) NOT NULL AUTO_INCREMENT,    ->   `X` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,    ->   PRIMARY KEY (`ID`)    -> ) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 ;Query OK, 0 rows affected (0.06 sec)mysql> insert into xdual(id,x) values(null,now());Query OK, 1 row affected (0.06 sec)

可以从控制台中看到：

empty count : 1empty count : 2empty count : 3empty count : 4================>; binlog[mysql-bin.001946:313661577] , name[test,xdual] , eventType : INSERTID : 4    update=trueX : 2013-02-05 23:29:46    update=true

最后：

如果需要更详细的exmpale例子，请下载canal当前最新源码包，里面有个example工程，谢谢.

Simple客户端例子：SimpleCanalClientTest
Cluster客户端例子：ClusterCanalClientTest

本文为https://github.com/alibaba/canal项目文档，仅作个人记录使用

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