取得Resultset的记录条数

public Boolean exists(String sql)
{
try {
stm = conn.createStatement(
java.sql.ResultSet.TYPE_SCROLL_INSENSITIVE,
java.sql.ResultSet.CONCUR_READ_ONLY);
rs = stm.executeQuery(sql);
rs.last();
int intRows=rs.getRow();
if (intRows == 0){
return false;
}else{
return true;
}
} catch (SQLException sqlexception) {
System.err.println("db.executeQuery:" + sqlexception.getMessage());
}catch (Exception e) {
// TODO: handle exception
System.err.println("db.executeQuery:" + e.getMessage());
}
return null;

}