从ResultSet中读取空值

Question

下表可能包含STA、ETA或ATA的空值:

CREATE TABLE `flightschedule` (
  `id` smallint(6) NOT NULL AUTO_INCREMENT,
  `flightNum_arr` varchar(40) DEFAULT NULL,
  `from_ICAO` varchar(20) DEFAULT NULL,
  `STA` datetime DEFAULT NULL,
  `ETA` datetime DEFAULT NULL,
  `ATA` datetime DEFAULT NULL,
  `pk_arr` varchar(10) DEFAULT NULL
  PRIMARY KEY (`id`)
) ENGINE=MyISAM AUTO_INCREMENT=5611 DEFAULT CHARSET=latin1;

查询为:

SELECT flightNum_arr,STA,ETA,ATA,airlineICAO,aircraftType,pk_arr FROM flightschedule";

当我尝试在Java代码中从这个表中读取数据时，会发生以下错误:

java.sql。不能转换值'0000-00-00 00:00:00'

出现在record[i] = rs.getString(i + 1);

行

我介绍了下面的检查，但它似乎不工作:

if(record[i] == null)
{
   record[i]= "";
}

代码:

public void setQuery(String query) {
        cache = new Vector();
        try {
          // Execute the query and store the result set and its metadata
          Connection con = getConnection();
          Statement statement = con.createStatement();
          ResultSet rs = statement.executeQuery(query);
          ResultSetMetaData meta = rs.getMetaData();
          colCount = meta.getColumnCount();
          // Rebuild the headers array with the new column names
          headers = new String[colCount];
          for (int h = 1; h <= colCount; h++) {
            headers[h - 1] = meta.getColumnName(h);
          }
          while (rs.next()) {
            String[] record = new String[colCount];
            for (int i = 0; i < colCount; i++) {
              record[i] = rs.getString(i + 1);
              if(record[i] == null)
              {
                  record[i]= "";
              }
            }
            cache.addElement(record);
          }
          fireTableChanged(null);         
          rs.close();
          if (con.getAutoCommit() != false) {
            con.close();
          }         
        } catch (Exception e) {
          cache = new Vector(); // blank it out and keep going.
          e.printStackTrace();
        }
      }

Answer 1

我认为问题是您需要配置连接以将0日期时间转换为空，每个以下帖子:

在JDBC中处理DATETIME值0000-00-00 00:00:00

Answer 2

您应该使用rs.getTimeStamp()或rs.getDate()来代替rs.getString对于DateTimeColum