Java Now getValidDate(String unknownDate)

Description

get Valid Date

License

Apache License

Declaration

public static String getValidDate(String unknownDate) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;

public class Main {
    public static final String DEFAULT_FOMATE = "yyyyMMdd";

    public static String getValidDate(String unknownDate) {
        if (unknownDate == null || !unknownDate.matches("[\\+|-]?[0-9]+")) {
            return null;
        }/*from   w  w w .  j  a v  a 2s  .  c o m*/

        Calendar calendar = Calendar.getInstance();
        int len = unknownDate.length();
        if (len < 4) { // 0, +2, -3, -16
            int days = Integer.parseInt(unknownDate);
            calendar.add(Calendar.DAY_OF_MONTH, days);
            return getDateStr(calendar);
        } else if (unknownDate.charAt(0) != '+' && unknownDate.charAt(0) != '-') {
            if (len == 8) { // 20160622
                return unknownDate;
            } else if (len == 6) { // 160622
                return (calendar.get(Calendar.YEAR) / 100) + unknownDate;
            } else if (len == 4) { // 0622
                return calendar.get(Calendar.YEAR) + unknownDate;
            }
        }

        return null;
    }

    public static String getDateStr(Calendar calendar, String format) {
        if (calendar == null || format == null) {
            return null;
        }

        try {
            SimpleDateFormat dateFormat = new SimpleDateFormat(format, Locale.US);
            return dateFormat.format(calendar.getTime());
        } catch (Exception e) {
        }

        return null;
    }

    public static String getDateStr(Calendar calendar) {
        return getDateStr(calendar, DEFAULT_FOMATE);
    }

    public static String getDateStr(Date date, String format) {
        if (date == null) {
            return null;
        }

        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);

        return getDateStr(calendar, format);
    }

    public static String getDateStr(Date date) {
        return getDateStr(date, DEFAULT_FOMATE);
    }

    public static String getDateStr(long time_millis, String format) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTimeInMillis(time_millis);

        return getDateStr(calendar, format);
    }

    public static String getDateStr(long time_millis) {
        return getDateStr(time_millis, DEFAULT_FOMATE);
    }

    public static String getDateStr(String format) {
        return getDateStr(System.currentTimeMillis(), format);
    }

    public static String getDateStr() {
        return getDateStr(DEFAULT_FOMATE);
    }
}

Related

1. getStringOfNowDate(String fFormatStr)
2. getTimeNow()
3. getTimeNow(Date theTime)
4. getTimeNowAsString(String pattern)
5. getTimeSubFromNowTime(String time)
6. isNowInInterval(String start, String end)
7. makeUniqueName(final String[] knownNames, final String pattern)
8. now()
9. now()