日期的简单封装

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

import org.apache.commons.lang.StringUtils;

public class DateUtil {

    public static long daysDiff(Date firstDay, Date lastDay) {
        if (firstDay == null || lastDay == null) {
            return 0;
        }
        long allDays = (lastDay.getTime() - (firstDay.getTime()))
                / (1000 * 24 * 60 * 60);

        return allDays;
    }

    public static Long yearDiff(Date firstDay, Date lastDay) {
        if (firstDay == null || lastDay == null)
            return null;
        Calendar first = Calendar.getInstance();
        first.setTime(firstDay);
        Calendar last = Calendar.getInstance();
        last.setTime(lastDay);
        long years = last.get(Calendar.YEAR) - first.get(Calendar.YEAR);
        return years;
    }

    public static Date addMinute(Date src, int minute) {
        Calendar c = Calendar.getInstance();
        c.setTime(src);
        c.add(Calendar.MINUTE, minute);
        return c.getTime();
    }

    public static String getTodayTextYMD() {
        DateFormat df = new SimpleDateFormat("yyyyMMdd");
        return df.format(new Date());

    }

    public static String getYesterdayTextYMD() {
        Calendar c = Calendar.getInstance();
        c.add(Calendar.DAY_OF_YEAR, -1);
        DateFormat df = new SimpleDateFormat("yyyyMMdd");
        return df.format(c.getTime());

    }

    public static Date getYesterday() {
        Calendar c = Calendar.getInstance();
        c.add(Calendar.DAY_OF_YEAR, -1);
        return c.getTime();
    }

    public static Date parseDateYMD(String ymd) {
        DateFormat df = new SimpleDateFormat("yyyyMMdd");
        try {
            return df.parse(ymd);
        } catch (ParseException e) {
            return getYesterday();
        }
    }
    
    public static Date parseDate(String strDate,String dateFormat) {
        DateFormat df = new SimpleDateFormat(dateFormat);
        try {
            return df.parse(strDate);
        } catch (ParseException e) {
            return null;
        }
    }
    
    /**
     * 将传入的日期以指定格式转成字符串
     * 
     * @param format
     * @param dt
     * @return
     */
    public static String formatDate(String format, Date dt) {
        if (dt == null) {
            return "";
        }
        if(StringUtils.isBlank(format)){
            return "";
        }
        
        SimpleDateFormat fmt = new SimpleDateFormat(format);
        return fmt.format(dt);
    }
    
    public static String getToday(){
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");
        return df.format(new Date());
    }
    
    /**
     * 获取给定日期的最后一天
     * @param dateStr
     * @return
     * @throws ParseException
     */
    public static Date getLastDayOfMonth(Date date) throws ParseException{
        if(date!=null){
            Calendar calendar = Calendar.getInstance();
            calendar.setTime(date);
            calendar.add(Calendar.MONTH, 1);
            calendar.set(Calendar.DAY_OF_MONTH,1);
            calendar.add(Calendar.DAY_OF_MONTH,-1);
            return calendar.getTime();
        }else{
            throw new IllegalArgumentException("The parameter dateStr not be specified!");
        }
    }
    
    public static int getDayOfWeek(Calendar calendar) {
        int today;
        if (calendar != null) {
            today = calendar.get(7);
        } else {
            today = Calendar.getInstance().get(7);
        }
        if (today == 1) {
            return 7;
        }
        return today - 1;
    }
    
    public static int getDayOfWeek(Date date) {
        if (date == null) {
            date = new Date();
        }

        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return getDayOfWeek(cal);
    }
}

import java.util.Calendar;
import java.util.Date;

public class DateUtils {

    /** 源日期格式 */
    private static final String SOURCE_DATE_PATTERN = "yyyy-MM-dd'T'HH:mm:ss";
    
    /** 目标日期格式 */
    private static final String TARGET_DATE_PATTERN = "yyyy-MM-dd HH:mm:ss";
    
    private static final String TARGET_DATE_PATTERN_01 = "yyyyMMdd";
    
    private static final String TARGET_DATE_PATTERN_02 = "yyyy-MM-dd";
    
    /**
     * 字符日期转Date
     * yyyy-MM-dd'T'HH:mm:ss
     *        |  源日期格式
     * @param scheduleDate
     * @return
     */
    public static Date convertDate(String scheduleDate){
        return DateUtil.parseDate(scheduleDate, SOURCE_DATE_PATTERN);
    }
    
    /**
     * 字符日期格式转换
     *  yyyy-MM-dd'T'HH:mm:ss
     *        |  源日期格式
     *  yyyy-MM-dd HH:mm:ss
     *        |  目标日期格式
     * @param scheduleDate
     * @return
     */
    public static String convertDate2Str(String scheduleDate){
        return convertDate2Str(scheduleDate, SOURCE_DATE_PATTERN, TARGET_DATE_PATTERN);
    }
    
    /**
     * 字符日期格式转换
     *  yyyy-MM-dd'T'HH:mm:ss
     *        |  源日期格式
     *  yyyyMMdd
     *        |  目标日期格式
     * @param scheduleDate
     * @return
     */
    public static String convertDate2Str01(String scheduleDate){
        return convertDate2Str(scheduleDate, SOURCE_DATE_PATTERN, TARGET_DATE_PATTERN_01);
    }
    /**
     * 字符日期格式转换
     *  yyyy-MM-dd'T'HH:mm:ss
     *        |  源日期格式
     *  yyyy-MM-dd
     *        |  目标日期格式
     * @param scheduleDate
     * @return
     */
    public static String convertDate2Str02(String scheduleDate){
        return convertDate2Str(scheduleDate, SOURCE_DATE_PATTERN, TARGET_DATE_PATTERN_02);
    }
    
    /**
     * 字符日期格式转换
     *  yyyy-MM-dd'T'HH:mm:ss
     *        |  源日期格式
     * @param scheduleDate
     * @param targetPattern  |  目标日期格式
     * @return
     */
    public static String convertDate2Str(String scheduleDate, String targetPattern){
        return convertDate2Str(scheduleDate, SOURCE_DATE_PATTERN, targetPattern);
    }
    
    /**
     * 字符日期格式转换
     * @param scheduleDate
     * @param sourcePattern  |  源日期格式
     * @param targetPattern  |  目标日期格式
     * @return
     */
    public static String convertDate2Str(String scheduleDate, String sourcePattern, String targetPattern){
        Date date = DateUtil.parseDate(scheduleDate, sourcePattern);
        return DateUtil.formatDate(targetPattern, date);
    }
    public static Date getYesterday() {
        Calendar c = Calendar.getInstance();
        c.add(Calendar.DAY_OF_YEAR, -1);
        return c.getTime();
    }
    
    /**
     * 
     * <p>
     * Sunday = 1
     * </p>
     * <p>
     * Monday = 2
     * </p>
     * <p>
     * Tuesday = 3
     * </p>
     * <p>
     * Wednesday = 4
     * </p>
     * <p>
     * Thursday = 5
     * </p>
     * <p>
     * Friday = 6
     * </p>
     * <p>
     * Saturday = 7
     * </p>
     * 
     * @param date
     * @return
     */
    public static int dayForWeek(Date date) {
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        int weekday = c.get(Calendar.DAY_OF_WEEK);
        return weekday;
    }
    
    public static boolean isSunday(Date date) {
        return (1 == dayForWeek(date));
    }
    
    public static boolean isSaturday(Date date) {
        return (7 == dayForWeek(date));
    }
}

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

import org.apache.commons.lang.StringUtils;

public class IDateUtil {
    private static SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
    private static SimpleDateFormat sdf0 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    private static SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd");
    
    public static String parseDateString(String s){
        if(s==null||"".equals(s)){
            return null;
        }else{
            try {
                return sdf0.format(sdf.parse(s));    
            } catch (ParseException e) {
//                e.printStackTrace();
                return s;
            }
        }
    }
    public static String parseString(Date date){
        if(date!=null){
            return sdf1.format(date);
        }
        return "";
    }
    
    public static Date parseDate(String dateStr){
        if(!StringUtils.isBlank(dateStr)){
            try {
                return sdf1.parse(dateStr);
            } catch (ParseException e) {
                return new Date();
            }
        }
        return new Date();
    }
    
    /**
     * 从身份证获取出生日期,id需要位15位或18位身份证，否则失败
     * @param id
     * @return
     * @throws ParseException 
     */
    public static Date getBirthday(String id) throws ParseException{
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMdd");
        if(id.trim().length() == 18){
            String birthday = id.substring(6, 14);
            Date date = dateFormat.parse(birthday);
            return date;
        }
        if(id.trim().length() == 15){
            String birthday = id.substring(6,12);
            Date date = dateFormat.parse("19" + birthday);
            return date;
        }
        return null;
    }
    
    /**
     * String转Date，根据formatStr的格式来，异常：ParseException
     * @param dateStr
     * @param formatStr
     * @return
     * @throws ParseException
     */
    public static Date parseDate(String dateStr, String formatStr) throws ParseException{
        SimpleDateFormat dateFormat = new SimpleDateFormat(formatStr);
        return dateFormat.parse(dateStr);
    }
    
    /**
     * Date转String，根据formatStr的格式来
     * @param date
     * @param formatStr
     * @return
     */
    public static String formatDate(Date date, String formatStr){
        SimpleDateFormat dateFormat = new SimpleDateFormat(formatStr);
        return dateFormat.format(date);
    }

    /**
     * 在相关时间上增加一定数量的天数,输入Date，输出Date
     * @param date
     * @param num
     * @return
     */
    public static Date addDay(Date date, int num) {
        Calendar startDT = Calendar.getInstance();
        startDT.setTime(date);
        startDT.add(Calendar.DAY_OF_MONTH, num);
        return startDT.getTime();
    }
    
}

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