处理日期java.util，日期java.sql和SimpleDateFormat

Question

I have trouble at handling different formats of dates in a program.

As it it now, my query is executed, but i get dates from DB in a YYYY-MM-DD format. I want them in DD-MM-YYYY HH:mm format.

In a SQL file, dates are defined like this (in an INSERT INTO instruction) :

to_date('2015/05/15 12:00', 'yyyy/mm/dd hh24:mi') 

In my java code, i try to make the user choose a date (Date object is a java.util.date) :

DateFormat formater = new SimpleDateFormat("DD-MM-YYYY HH:mm", Locale.FRENCH);
String dateString;
dateString = sc.nextLine();
Date upperDate = formater.parse(dateString);
// a "lowerDate is also that way.

    List<Train> listTrains = new ArrayList<>();
            listTrains = manager.WhenTrain(departure_city, arrival_city, upperDate, lowerDate);

for(int i = 0; i<liste.size(); i++)
    {
        System.out.println(listTrains.get(i));
    }

In a method, i try to get values corresponding to various conditions, among them, dates, so i have :

In the constructor and fields :

    private PreparedStatement AllTrains;
    private PreparedStatement LookForDepartureStation;

    AllTrains = connection.prepareStatement("SELECT * FROM Trains"
                    + "WHERE departure = ? AND arrival = ? AND departurehour BETWEEN ? AND ?"); // Trains is a view, joining several table
 LookForDepartureStation = connection.prepareStatement("SELECT * from Journey where departure = ?");

In another method :

    public List<Train> WhenTrain(String departureStation, String arrivalStation, java.util.Date dateBefore, java.util.Date dateAfter) {

        ArrayList<Train> TrainList= new ArrayList<>();

        try {


            java.sql.Date begin = new java.sql.Date(dateBefore.getTime());
            java.sql.Date end = new java.sql.Date(dateAfter.getTime());


            LookForDepartureStation.setString(1, departureStation);
            ResultSet test1 = LookForDepartureStation.executeQuery();

            if(test1.next()){

                  LookForDepartureStation.close();
                  LookForArrivalStation.setString(1, arrivalStation);
                  ResultSet test2 = LookForArrivalStation.executeQuery();

                  if(test2.next()) {
                      LookForArrivalStation.close();

                      AllTrains.setString(1, departureStation);
                      AllTrains.setString(2, arrivalStation);
                      AllTrains.setDate(3, begin);
                      AllTrains.setDate(4, end);

                      ResultSet rs = AllTrains.executeQuery();

                         while(rs.next()){
                               TrainList.add(new Train(rs.getInt(1), 

    rs.getString(2), rs.getString(3), rs.getDate(4), rs.getDate(5))); 
    // Train is an object to take all those.
    // AllTrains contains  TrainID (an oracle integer), departure (varchar2), arrival (varchar2), departurehour (sql oracle DATE), arrivalhour (sql oracle DATE)


           }
                   // AllTrains.close();
                     return ListeTrains;
                  }
                  else {
                      System.out.println("wrong input on arrival station");
                    //  AllTrains.close();
TrainApp.Alltrains(this);
                      return TrainList;
                  }
            } 
            else {
               System.out.println("wrong input on departure station");

               return TrainList;
            }

        } catch (SQLException error) {
            error.printStackTrace();

           return TrainList;
      }
             catch(NullPointerException e) {
              System.out.println("Station not found");
              e.printStackTrace();
              TrainApp.Alltrains(this); // calling back static method to try again the input.
               return TrainList;
          }

}      

When i try to pass Upperdate in the method, debugger shows that the variable contains : "1 janv. 0003 00:00:00" (I tried with 03-11-1993 actually). Moreover i don't think it will put the date i want in the Train object, i think i messed that up too.

The program ends without showing me what is in the list (the instructions after the method call, as you see in the 2nd code quote here).

Answer 1

Without knowing the values of upperDate and lowerDate it's hard to see why they are not parsed correctly.

The problem with the query is that java.sql.Date rounds the java.util.Date value in input to the day, ie it resets the time part. You must use java.sql.TimeStamp if you want to query and retrieve the correct results with the time part. Try change begin and end type to java.sql.TimeStamp and rs.getDate(4), rs.getDate(5) to rs.getTimestamp(4), rs.getTimestamp(5)

The misunderstanding usually starts because the type Date in Oracle contains also the time part, but in other RDBMS the date type represents "only" a date