主类 

• 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.FlatMessage;
  import com.alibaba.otter.canal.protocol.Message;
  import com.google.protobuf.ByteString;
  import com.google.protobuf.InvalidProtocolBufferException;
  
  import java.net.InetSocketAddress;
  import java.util.*;
  import java.util.concurrent.TimeUnit;
  
  public class FlatmessageParse{
  
      /*Canal 客户端*/
      // Canal 服务器地址
      private static final String SERVER_ADDRESS = "192.168.8.88";
      // Canal 端口 默认 11111
      private static final Integer PORT = 11111;
      // Canal 目的地即 canal 配置实例
      private static final String DESTINATION = "example";
      // Canal 用户名密码 默认为空
      private static final String USERNAME = "";
      private static final String PASSWORD = "";
      private static CanalConnector canalConnector;
  }

main方法入口

•  public static void main(String[] args) {
  
          canalConnector = CanalConnectors.newSingleConnector(
                  new InetSocketAddress(SERVER_ADDRESS, PORT),
                  DESTINATION, USERNAME, PASSWORD);
          try {
              //建立连接
              canalConnector.connect();
              // 订阅
              canalConnector.subscribe(".*\\..*");
              //  while(true) {
              int batchSize = 1000;
              // 获取指定数量的数据
              Message message = canalConnector.getWithoutAck(batchSize, 1000L, TimeUnit.MILLISECONDS);
              Long batchId = message.getId();
              int size = message.getEntries().size();
              if (batchId == -1 || size == 0) {
                  System.out.println("message信息有误");
              } else {
                  //存在数据，解析处理
                  List<FlatMessage> flatMessages = parseFlatMessage(message);
                  Iterator flatMessages_iterator = flatMessages.iterator();
                  while (flatMessages_iterator.hasNext()) {
                      System.out.println(flatMessages_iterator.next() + ",");
                  }
              }
  
              canalConnector.ack(batchId); // 提交确认 处理数据
              // connector.rollback(batchId); // 处理失败, 回滚数据
              //  }
          } finally {
              canalConnector.disconnect();
          }
      }

解析方法 

•     public static List<FlatMessage> parseFlatMessage(Message message) {
          try {
              if (message == null) {
                  return null;
              } else {
                  List<FlatMessage> flatMessages = new ArrayList();
                  List<CanalEntry.Entry> entries = message.getEntries();
  
                  //遍历entry   entry--------->flatmessage
                  for (CanalEntry.Entry entry : entries) {
                      CanalEntry.Header header = entry.getHeader();
                      CanalEntry.EntryType entryType = entry.getEntryType();
                      //如果是事务则先忽略
                      if (entryType == CanalEntry.EntryType.TRANSACTIONBEGIN
                              || entryType == CanalEntry.EntryType.TRANSACTIONEND) {
                          continue;
                      }
                      CanalEntry.EventType eventType = header.getEventType();
                      ByteString storeValue = entry.getStoreValue();
                      CanalEntry.RowChange rowChange = null;
                      try {
                          rowChange = CanalEntry.RowChange.parseFrom(storeValue);
                      } catch (InvalidProtocolBufferException e) {
                          e.printStackTrace();
                      }
  
                      //基本类型
                      FlatMessage flatMessage = new FlatMessage(message.getId());
                      flatMessage.setEs(header.getExecuteTime());
                      flatMessage.setTable(header.getTableName());
                      flatMessage.setDatabase(header.getSchemaName());
                      flatMessage.setType(eventType.toString());
                      flatMessage.setIsDdl(rowChange.getIsDdl());
                      flatMessage.setSql(rowChange.getSql());
                      flatMessage.setTs(System.currentTimeMillis());
  
                      if (!rowChange.getIsDdl()) {
                          //定义复杂类型
                          Map<String, Integer> sqlType = new LinkedHashMap();
                          Map<String, String> mysqlType = new LinkedHashMap();
                          List<Map<String, String>> data = new ArrayList();
                          List<Map<String, String>> old = new ArrayList();
                          Set<String> updateSet = new HashSet();
  
                          List<CanalEntry.RowData> rowDatas = rowChange.getRowDatasList();
                          //遍历rowDatas
                          for (CanalEntry.RowData rowData : rowDatas) {
                              //只分析insert update，delete
                              if (eventType != CanalEntry.EventType.INSERT && eventType != CanalEntry.EventType.UPDATE
                                      && eventType != CanalEntry.EventType.DELETE) {
                                  continue;
                              }
  
                              Map<String, String> row = new LinkedHashMap();
                              List<CanalEntry.Column> columns;
                              if (eventType == CanalEntry.EventType.DELETE) {
                                  columns = rowData.getBeforeColumnsList();
                              } else {
                                  columns = rowData.getAfterColumnsList();
                              }
                              for (CanalEntry.Column column : columns) {
                                  sqlType.put(column.getName(), column.getSqlType());
                                  mysqlType.put(column.getName(), column.getMysqlType());
                                  if (column.getIsNull()) {
                                      row.put(column.getName(), null);
                                  } else {
                                      row.put(column.getName(), column.getValue());
                                  }
                                  // 获取update为true的字段
                                  if (column.getUpdated()) {
                                      updateSet.add(column.getName());
                                  }
                              }
                              if (!row.isEmpty()) {
                                  data.add(row);
                              }
  
                              //update再添加old
                              Map<String, String> rowOld = new LinkedHashMap<>();
                              if (eventType == CanalEntry.EventType.UPDATE) {
                                  for (CanalEntry.Column column : rowData.getBeforeColumnsList()) {
                                      if (updateSet.contains(column.getName())) {
                                          if (column.getIsNull()) {
                                              rowOld.put(column.getName(), null);
                                          } else {
                                              rowOld.put(column.getName(), column.getValue());
                                          }
                                      }
                                  }
                              }
                              // update操作再添加before的值
                              if (!rowOld.isEmpty()) {
                                  old.add(rowOld);
                              }
                          }
  
                          if (!sqlType.isEmpty()) {flatMessage.setSqlType(sqlType);}
                          if (!mysqlType.isEmpty()) { flatMessage.setMysqlType(mysqlType);}
                          if (!data.isEmpty()) {flatMessage.setData(data);}
                          if (!old.isEmpty()) {flatMessage.setOld(old);}
                      }
  
                      flatMessages.add(flatMessage);
                  }
                  return flatMessages;
              }
  
          } catch (Exception e) {
              throw new RuntimeException(e);
          }
      }