canal基于自定义注解使用【java】

1、引入pom文件

      <dependency>
          <groupId>com.alibaba.otter</groupId>
          <artifactId>canal.client</artifactId>
          <version>1.1.4</version>
      </dependency>

2、自定义注解【BinLogs】

import java.lang.annotation.*;

@Target({ ElementType.METHOD })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface BinLogs
{
}

3、注解实现类【BinLogsValidator】

import com.alibaba.fastjson.JSONObject;
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 org.apache.commons.lang3.ObjectUtils;
import org.aspectj.lang.annotation.After;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.annotation.Pointcut;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.net.InetSocketAddress;
import java.util.List;

/**
 * 注解实现
 */
@Component
@Aspect
public class BinLogsValidator {
    private static final int BATCH_SIZE = 10;

    // 可使用常量，也可用yml配置
    // @Value("${common.canalurl}")
    private String canalUrl = "10.0.0.11";
    // @Value("${common.canalport}")
    private Integer canalport = 111111;

    @Resource
    @Qualifier("taskExecutor")
    private ThreadPoolTaskExecutor poolTaskExecutor;

    /**
     * 定义切入点
     */
    @Pointcut("@annotation(BinLogs)")
    public void noRepeat() {
    }

    /**
     * 后置通知：在连接点之后执行通知
     */
    @After("noRepeat()")
    public void after() {
        //可携带入参
        String url = canalUrl;
        Integer port = canalport;
        poolTaskExecutor.execute(() -> dealAop(url, port));
    }

    private static void dealAop(String canalUrl, Integer canalport) {
        CanalConnector connector = CanalConnectors.newSingleConnector(new InetSocketAddress(canalUrl, canalport),
                "example", "", "");
        try {
            // 打开连接
            connector.connect();
            // 订阅数据库表,全部表
            connector.subscribe(".*\\..*");
            // 回滚到未进行ack的地方，下次fetch的时候，可以从最后一个没有ack的地方开始拿
            connector.rollback();
            while (true) {
                // 获取指定数量的数据
                Message message = connector.getWithoutAck(BATCH_SIZE);
                // 获取批量ID
                long batchId = message.getId();
                // 获取批量的数量
                int size = message.getEntries().size();
                // 如果没有数据
                if (batchId == -1 || size == 0) {
                    try {
                        // 线程休眠2秒
                        Thread.sleep(2000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                } else {
                    // 如果有数据,处理数据
                    printEntry(message.getEntries());
                }
                // 进行 batch id 的确认。确认之后，小于等于此 batchId 的 Message 都会被确认。
                connector.ack(batchId);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            connector.disconnect();
        }
    }

    /**
     * 打印canal server解析binlog获得的实体类信息
     */
    private static void printEntry(List<CanalEntry.Entry> entrys) {
        for (CanalEntry.Entry entry : entrys) {
            if (entry.getEntryType() == CanalEntry.EntryType.TRANSACTIONBEGIN
                    || entry.getEntryType() == CanalEntry.EntryType.TRANSACTIONEND) {
                // 开启/关闭事务的实体类型，跳过
                continue;
            }
            // RowChange对象，包含了一行数据变化的所有特征
            // 比如isDdl 是否是ddl变更操作 sql 具体的ddl sql beforeColumns afterColumns 变更前后的数据字段等等
            CanalEntry.RowChange rowChage;
            try {
                rowChage = CanalEntry.RowChange.parseFrom(entry.getStoreValue());
            } catch (Exception e) {
                throw new RuntimeException("ERROR ## parser of eromanga-event has an error , data:" + entry, e);
            }
            // 获取操作类型：insert/update/delete类型
            CanalEntry.EventType eventType = rowChage.getEventType();
            // 表名称
            String tableName = entry.getHeader().getTableName();
            // binlog文件名称
            String binlog = entry.getHeader().getLogfileName() + ":" + entry.getHeader().getLogfileOffset();
            // 打印Header信息
            System.out.println("操作的binlog:" + binlog);
            System.out.println("操作的表:" + entry.getHeader().getSchemaName() + "." + tableName);
            System.out.println("操作类型:" + eventType);
            if ("sys_binlogs".equals(tableName)) {
                return;
            }
            // 判断是否是DDL语句
            if (rowChage.getIsDdl()) {
                System.out.println("================》;isDdl: true,sql:" + rowChage.getSql());
            }
            // 获取RowChange对象里的每一行数据，打印出来
            for (CanalEntry.RowData rowData : rowChage.getRowDatasList()) {
                // 如果是删除语句
                if (eventType == CanalEntry.EventType.DELETE) {
                    JSONObject jsonObject = printColumn(rowData.getBeforeColumnsList());
                    System.out.println("删除语句:" + jsonObject);
                    // 获取删除的sql
                    StringBuffer stringBuffer = saveDeleteSql(rowData, tableName);
                    System.out.println("删除Sql:" + stringBuffer);
                    //todo 可处理业务逻辑
                } // 如果是新增语句
                else if (eventType == CanalEntry.EventType.INSERT) {
                    JSONObject jsonObject = printColumn(rowData.getAfterColumnsList());
                    System.out.println("新增语句:" + jsonObject);

                    // 获取插入的sql
                    StringBuffer stringBuffer = saveInsertSql(rowData, tableName);
                    System.out.println("新增Sql:" + stringBuffer);
                    //todo 可处理业务逻辑
                } // 如果是更新的语句
                else {
                    // 变更后的数据
                    System.out.println("------->; after");
                    JSONObject after = printColumn(rowData.getAfterColumnsList());
                    System.out.println("变更后的数据:" + after);
                    // 变更前的数据
                    System.out.println("------->; before");
                    JSONObject before = printBeforeColumn(rowData.getBeforeColumnsList(), after);
                    System.out.println("变更前的数据:" + before);
                    JSONObject jsonObject = new JSONObject();
                    jsonObject.put("before", before);
                    jsonObject.put("after", after);

                    // 获取修改的sql
                    StringBuffer stringBuffer = saveUpdateSql(rowData, tableName);
                    System.out.println("更新Sql:" + stringBuffer);
                }
            }
        }
    }

    /**
     * 变更前的数据内容（根据变更后的字段进行取值操作）
     *
     * @param columns 变更前的数据每一行
     * @param after   变更后的字段key:value
     */
    private static JSONObject printBeforeColumn(List<CanalEntry.Column> columns, JSONObject after) {
        if (ObjectUtils.isEmpty(after)) {
            return new JSONObject();
        }
        JSONObject jsonObject = new JSONObject();
        for (CanalEntry.Column column : columns) {
            if (org.apache.commons.lang3.ObjectUtils.isNotEmpty(after.get(column.getName()))) {
                jsonObject.put(column.getName(), column.getValue());
            }
        }
        return jsonObject;
    }

    /**
     * 处理数据库表数据变更
     *
     * @param columns 数据库表数据变更的每一行
     */
    private static JSONObject printColumn(List<CanalEntry.Column> columns) {
        JSONObject jsonObject = new JSONObject();
        for (CanalEntry.Column column : columns) {
            if (column.getUpdated()) {
                jsonObject.put(column.getName(), column.getValue());
            }
        }
        return jsonObject;
    }

    /**
     * 保存更新语句
     */
    private static StringBuffer saveUpdateSql(CanalEntry.RowData rowData, String tableName) {
        List<CanalEntry.Column> newColumnList = rowData.getAfterColumnsList();
        StringBuffer sql = new StringBuffer("update " + tableName + " set ");
        for (int i = 0; i < newColumnList.size(); i++) {
            if (newColumnList.get(i).getUpdated()) {
                sql.append(" ").append(newColumnList.get(i).getName()).append(" = '")
                        .append(newColumnList.get(i).getValue()).append("'");
                if (i != newColumnList.size() - 1) {
                    sql.append(",");
                }
            }
        }
        sql.append(" where ");
        List<CanalEntry.Column> oldColumnList = rowData.getBeforeColumnsList();
        for (CanalEntry.Column column : oldColumnList) {
            if (column.getIsKey()) {
                // 暂时只支持单一主键
                sql.append(column.getName()).append("=").append(column.getValue());
                break;
            }
        }
        return sql;
    }

    /**
     * 保存删除语句
     */
    private static StringBuffer saveDeleteSql(CanalEntry.RowData rowData, String tableName) {
        List<CanalEntry.Column> columnList = rowData.getBeforeColumnsList();
        StringBuffer sql = new StringBuffer("delete from " + tableName + " where ");
        for (CanalEntry.Column column : columnList) {
            if (column.getIsKey()) {
                // 暂时只支持单一主键
                sql.append(column.getName()).append("=").append(column.getValue());
                break;
            }
        }
        return sql;
    }

    /**
     * 保存插入语句
     */
    private static StringBuffer saveInsertSql(CanalEntry.RowData rowData, String tableName) {
        List<CanalEntry.Column> columnList = rowData.getAfterColumnsList();
        StringBuffer sql = new StringBuffer("insert into " + tableName + " (");
        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("'").append(columnList.get(i).getValue()).append("'");
            if (i != columnList.size() - 1) {
                sql.append(",");
            }
        }
        sql.append(")");
        return sql;
    }

4、接口使用注解

将此注解加到对应的接口上就行 @BinLogs