如何将字符串类型的日期转换为日期以进入 Oracle DB - Java

Question

Incoming date format id 2014-11-03 00.00.00.0 and need to be converted to either 03/11/2014 or 03-Nov-2014.

What could be the best possible and smallest code?

Answer 1

OK, so you have a String with the value 2014-11-03 00.00.00.0 and you want to insert that value in a DATE field inside a Oracle Database Table, using Java's JDBC?

Well, first, convert that String into a Date object using a SimpleDateFormat object:

String s = "2014-11-03 00.00.00.0";
Date d = new SimpleDateFormat("yyyy-MM-dd HH.mm.ss.S").parse(s);

Then, if you are using plain statements, reformat it the way Oracle would accept it in an SQL INSERT command, using again a SimpleDateFormat object:

String sd = new SimpleDateFormat("dd/MM/yyyy").format(d);

and insert it into your Statement:

cn.createStatement().executeUpdate("INSERT INTO TABLE(...) VALUES(" + sd + ");

I would recommend you to better use a PreparedStatement instead of a plain SQL INSERT statement so your statement is sanitized:

PreparedStatement ps = cn.prepareStatement("INSERT INTO table VALUES(?, ?, ?)");

And then, insert your date as a Date object without the need of formatting into a String:

ps.setDate([index of the field to insert], d);

Answer 2

If you're using java 8 there's a very useful date format class java.time.format.DateTimeFormatter With that class you can do something like these:

LocalDate date = LocalDate.now();
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH.mm.ss");
String text = date.format(formatter);
LocalDate parsedDate = LocalDate.parse(text, formatter);

DateTimeFormatter formatter2 = DateTimeFormatter.ofPattern("MM/DD/YYYY");
String newText = parsedDate.format(formatter2);

Answer 3

试试这个代码：

Date d = new SimpleDateFormat("dd/MM/yyyy").parse(date);

Answer 4

In java 8 getting a java.sql.Date (= java.util.Date with zero time) from that string may use a formatter, but as the string is almost ISO standard:

    LocalDateTime x = LocalDateTime.parse("2014-11-03T00:00:00.0");

one could patch the string as:

    LocalDateTime t = LocalDateTime.parse("2014-11-03 00.00.00.0"
            .replaceFirst(" ", "T") // Make ISO
            .replaceFirst("\\.", ":")
            .replaceFirst("\\.", ":"));

    java.sql.Date time = java.sql.Date.valueOf(t.toLocalDate());

Or

    LocalDate t = LocalDate.parse("2014-11-03 00.00.00.0"
            .replaceFirst(" .*$", "")); // Remove time part
    java.sql.Date time = java.sql.Date.valueOf(t);

Answer 5

tl;dr

myPreparedStatement.setObject( 
    … , 
    LocalDate.parse(  "2014-11-03 00.00.00.0".substring( 0 , 10 ) ) 
); 

What could be the best possible and smallest code?

There you go. But I do not recommend actually crunching so much into a single line. The “best” code is rarely the “smallest” code.

Details

Other answers are correct. But here is something shorter.

First of all, you should not be submitting a date-only value to a database as a string. Submit as a date-only object. Your JDBC driver will handle the details of communicating that to the database.

First extract your date value by calling String::substring . With padding zeros on month and day-of-month we know the first 10 digits are the date.

LocalDate ld = LocalDate.parse(  "2014-11-03 00.00.00.0".substring( 0 , 10 ) );

If your JDBC driver complies with JDBC 4.2 or later, you can pass the LocalDate directly via PreparedStatement::setObject .

myPreparedStatement.setObject( … , ld );

…or perhaps:

myPreparedStatement.setObject( … , ld , JDBCType.DATE );

If your driver does not comply, convert to the legacy class java.sql.Date . Look to new methods added to the old classes.

java.sql.Date sqlDate = java.sql.Date.valueOf( ld );

The approach described here assumes the input string was intended for UTC . If not, you need to adjust into UTC. Search Stack Overflow for posts on parsing a string as a ZonedDateTime .

Answer 6

This also works for me. a small utility method to generate a string value of a date that can be inserted into an Oracle Database Date Field, abit dirty but works. first function uses Calender class and second one LocalDate ( Java8 or higher )

1.

      /*
     * Format Date for Presentation in format
     * 19-DEC-2019   i.e. Oracle DB DD-MMM-YYYYY
     */
    private String stringToDate(String inputDate) {
        String finalDate = null;
        if (inputDate == null)
            return null;

        try {
            Date parseDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(inputDate);

            // set your local time zone
            Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("Africa/Lusaka"));
            cal.setTime(parseDate);
            String finalMonth = "";
            int yearVal = cal.get(Calendar.YEAR);
            int monthVal = cal.get(Calendar.MONTH);  //returns value 0 to 11
            int dayVal = cal.get(Calendar.DAY_OF_MONTH);

            switch(monthVal) {
            case 0:
                finalMonth = "JAN";
                break;
            case 1:
                finalMonth = "FEB";
                break;
            case 2:
                finalMonth = "MAR";
                break;
            case 3:
                finalMonth = "APR";
                break;
            case 4:
                finalMonth = "MAY";
                break;
            case 5:
                finalMonth = "JUN";
                break;
            case 6:
                finalMonth = "JUL";
                break;
            case 7:
                finalMonth = "AUG";
                break;
            case 8:
                finalMonth = "SEP";
                break;
            case 9:
                finalMonth = "OCT";
                break;
            case 10:
                finalMonth = "NOV";
                break;
            case 11:
                finalMonth = "DEC";
                break;

            }

            finalDate = dayVal+"-"+finalMonth+"-"+yearVal;

        } catch (ParseException e) {
            e.printStackTrace();
        }

        return finalDate;
    }

2.

       /*
     * Format Date for Presentation in format
     *  19-DEC-2019   i.e. Oracle DB DD-MMM-YYYYY
     */
    private String stringToDateJava8(String inputDate) {
        String finalDate = null;
        if (inputDate == null)
            return null;

        try {
            Date parseDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(inputDate);

            String finalMonth = "";
            LocalDate localDate = parseDate.toInstant().atZone(ZoneId.systemDefault()).toLocalDate();
            int yearVal  = localDate.getYear();
            int monthVal = localDate.getMonthValue();   //returns value 1 to 12
            int dayVal   = localDate.getDayOfMonth();

            switch(monthVal) {
            case 1:
                finalMonth = "JAN";
                break;
            case 2:
                finalMonth = "FEB";
                break;
            case 3:
                finalMonth = "MAR";
                break;
            case 4:
                finalMonth = "APR";
                break;
            case 5:
                finalMonth = "MAY";
                break;
            case 6:
                finalMonth = "JUN";
                break;
            case 7:
                finalMonth = "JUL";
                break;
            case 8:
                finalMonth = "AUG";
                break;
            case 9:
                finalMonth = "SEP";
                break;
            case 10:
                finalMonth = "OCT";
                break;
            case 11:
                finalMonth = "NOV";
                break;
            case 12:
                finalMonth = "DEC";
                break;

            }

            finalDate = dayVal+"-"+finalMonth+"-"+yearVal;

        } catch (ParseException e) {
            e.printStackTrace();
        }

        return finalDate;
    }