dateutil.java

java日期处理工具类

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

import org.apache.commons.lang.StringUtils;

public class DateUtil {
	public static final String DEFAULT_DATE_PATTERN = "yyyy-MM-dd";
	
	public static final String DEFAULT_DATE_PATTERN_1 = "yyyy.MM.dd";
	
	public static final String DEFAULT_DATE_TIME_PATTERN = "yyyy-MM-dd HH:mm:ss";
	
	/**
	 * 以默认日期格式返回当前日期（yyyy-MM-dd）
	 * @return String 当前日期
	 */
	public static String getYMD(){
		Calendar calendar = Calendar.getInstance();
		return new SimpleDateFormat(DEFAULT_DATE_PATTERN).format(calendar.getTime());
	}
	

	public static String setDateToStr(Date date){
		if(date==null){
			return null;
		}
		return new SimpleDateFormat(DEFAULT_DATE_PATTERN_1).format(date);
	}
	

	public static String getYMDHMS(){
		Calendar calendar = Calendar.getInstance();
		return new SimpleDateFormat(DEFAULT_DATE_TIME_PATTERN).format(calendar.getTime());
	}
	

	public static String getYMDHM(){
		Calendar calendar = Calendar.getInstance();
		return new SimpleDateFormat("yyyy-MM-dd HH:mm").format(calendar.getTime());
	}

	public static Date getSysDate(){
		return new Date();
	}
	

	public static Date toDate(String ymd) {
    Date returnValue = null;
    if (ymd != null && !ymd.equals("")) {
      DateFormat df = DateFormat.getDateInstance();
      try {
        returnValue = df.parse(ymd);
      } catch (ParseException pe) {}
    }
    return returnValue;
  }
	

	public static String getYear(Date _date){
		return FormatUtil.formatDate(_date, "yyyy");
	}
	

	public static String getYear(String _date){
		return FormatUtil.formatDate(toDate(_date), "yyyy");
	}


	public static String getMonth(Date _date){
		return FormatUtil.formatDate(_date, "MM");
	}
	

	public static String getMonth(String _date){
		return FormatUtil.formatDate(toDate(_date), "MM");
	}
	

	public static String getDay(Date _date){
		return FormatUtil.formatDate(_date, "dd");
	}
	
	public static boolean isDivideExactly(String _date, int dividend){
		boolean rValue = false;
		if ((Integer.parseInt(getDay(_date)) == dividend)){
			rValue = true;
		}
		return rValue;
	}
	
	public static boolean isLastDay(String _date){
		return isLastDay(toDate(_date));
	}
	
	public static boolean isLastDay(Date _date){
		boolean rValue = false;
		Calendar calendar = Calendar.getInstance();
		calendar.set(Integer.parseInt(getYear(_date)), Integer.parseInt(getMonth(_date)) - 1, Integer.parseInt(getDay(_date)));
		if (Integer.parseInt(getDay(_date)) == calendar.getActualMaximum(Calendar.DAY_OF_MONTH)){
			rValue = true;
		}
		return rValue;
	}
	
	public static boolean isFirstDay(String _date){
		return isFirstDay(toDate(_date));
	}
	
	public static boolean isFirstDay(Date _date){
		boolean rValue = false;
		Calendar calendar = Calendar.getInstance();
		calendar.set(Integer.parseInt(getYear(_date)), Integer.parseInt(getMonth(_date)) - 1, Integer.parseInt(getDay(_date)));
		if (Integer.parseInt(getDay(_date)) == calendar.getActualMinimum(Calendar.DAY_OF_MONTH)){
			rValue = true;
		}
		return rValue;
	}

	public static String getDay(String _date){
		return FormatUtil.formatDate(toDate(_date), "dd");
	}
	

	public static String add(String datePart, String _date, int count){
		return add(datePart, toDate(_date), count);
	}
	

	public static String add(String datePart, Date _date, int count){
		Calendar calendar = Calendar.getInstance();
		calendar.set(Integer.parseInt(getYear(_date)), Integer.parseInt(getMonth(_date)) - 1, Integer.parseInt(getDay(_date)));
		calendar.add(java.util.Calendar.DAY_OF_MONTH, count);
		return new SimpleDateFormat(DEFAULT_DATE_PATTERN).format(calendar.getTime());
	}

	public static String[] getPreviousSelYearStr(){
		int maxLength = 10;
    String[] lpYearArr = new String[maxLength];
    String lpYear;
    lpYear = FormatUtil.formatDate(getSysDate(), "yyyy");
    for(int i = 0; i < 10; i++){
    	lpYearArr[i] = String.valueOf(Integer.parseInt(lpYear) - i);
    }
     return lpYearArr;
  }
	

	public static String[] getSelMonthStr(){
		int maxLength = 12;
    String[] lpMonthArr = new String[maxLength];
    for (int i = 1; i <= 12; i++){
    	lpMonthArr[i - 1] = StringUtil.intToStr(i, 2);
     }
    return lpMonthArr;
  }
	
	public static String dateToStr(Date date) {
		String ymd = "";

		StringBuffer backstr = new StringBuffer();
		if (date == null) {
			backstr.append("");
		} else {
			ymd = DateFormat.getDateInstance().format(date);
			if (ymd != null && ymd.charAt(1) != '-') {
				String[] ymdArr = StringUtils.split(ymd, "-");
				if (ymdArr.length >= 2) {
					String y = ymdArr[0];
					String m = ymdArr[1];
					if (m.length() == 1)
						m = "0".concat(m);
					String d = ymdArr[2];
					if (d.length() == 1)
						d = "0".concat(d);
					backstr.append(y).append("-").append(m).append("-").append(d);
				} else
					backstr.append("");
			} else {
				backstr.append("");
			}
		}
		return backstr.toString();
	}


	public static Date strToDate(String strn) {
		Date returnValue = null;

		if (strn != null && !strn.equals("")) {
			DateFormat df = DateFormat.getDateInstance();
			try {
				returnValue = df.parse(strn);
			} catch (ParseException pe) {
			}
		}
		return returnValue;
	}
	

	public static String getYMD(int n) {
		Date date=new Date();//取时间
        Calendar calendar = new GregorianCalendar();
        calendar.setTime(date);
        calendar.add(calendar.DATE,n);
        date=calendar.getTime();     
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
        String dateString = formatter.format(date);
		return dateString;
	}
	
	/////////////////////////////////////
	public static void main(String[] args) {
		System.out.println(DateUtil.getYMDHMS());
	}

}