Canal 使用入门 - 客户端 - 我的博客 - CSDN博客 - 非kafka有例程 -- 没太大用

安宇雨 - 随手采集
2019-09-10 18:37:37
随手采集
0000-未整理-等待研究

需要依赖Maven。

1.修改POM文件（pom.xml），添加依赖：

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

2.建立测试类：
TestCanal.java

import java.net.InetSocketAddress;
import java.util.List;

import com.alibaba.otter.canal.client.CanalConnector;
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;
import com.alibaba.otter.canal.client.*;

public class TestCanal {

    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 = 1200;
            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) {
                        e.printStackTrace();
                    }
                } 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());
        }
    }

}

3.运行测试类，可以看到控制台如下输出：

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

4.此时通过SQL对数据进行操作：

INSERT：

INSERT TABLEA (ID, NAME) VALUES (1, 'A');
INSERT TABLEA (ID, NAME) VALUES (2, 'B');
INSERT TABLEA (ID, NAME) VALUES (3, 'C');

UPDATE：

UPDATE TABLEA SET NAME = 'AA' WHERE ID = 1;

DELETE：

DELETE FROM TABLEA WHERE ID = 1;

5.在控制台中可以查看到数据库操作的推送信息：

INSERT:
================> binlog[mysql-bin.000001:13290] , name[test,tablea] , eventType : INSERT
id : 1    update=true
name : A    update=true
id : 2    update=true
name : B    update=true
id : 3    update=true
name : C    update=true

UPDATE:
================> binlog[mysql-bin.000001:13466] , name[test,tablea] , eventType : UPDATE
-------> before
id : 1    update=false
name : A    update=false
-------> after
id : 1    update=false
name : AA    update=true

DELETE:
================> binlog[mysql-bin.000001:13874] , name[test,tablea] , eventType : DELETE
id : 1    update=false
name : AA    update=false
id : 2    update=false
name : B    update=false
id : 3    update=false
name : C    update=false

Original url: Access
Created at: 2019-09-10 18:37:37
Category: default
Tags: none

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