java工具类------日期工具类-蒲公英云

1.不多说直接上代码，小伙伴们可以看注释，代码如下：

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
/**
 * @ClassName: DateUtil
 * @Description: 日期工具类
 * @author wangXi
 * @date 
 */
public class DateUtil
{
    /**
     * @Title: formatDate
     * @Description: 格式化日期
     * @param date
     * @param formatString
     * @return String
     */
    public static String formatDate(Date date, String formatString)
    {
        SimpleDateFormat format = new SimpleDateFormat(formatString);
        return format.format(date);
    }
    /**
     * @Title: fromStringToDate
     * @Description: 自定义日期，注意 日期字符串需和fomat保持一致
     * @param fomat
     *            例：yyyy-MM-dd
     * @param dateStr
     *            例：2015-01-01
     * @return Date
     * @throws ParseException
     */
    public static Date fromStringToDate(String fomat, String dateStr)
            throws ParseException
    {
        Date date = null;
        date = new SimpleDateFormat(fomat).parse(dateStr);
        return date;
    }
    /**
     * @Title: currentDayMinus
     * @Description: 根据系统参数对当前日期进行相减操作
     * @param formatString 日期格式
     * @param days
     * @return String 当前日期相减后的日期
     */
    @SuppressWarnings("static-access")
    public static String currentDayMinus(int days, String formatString)
    {
        DateFormat format = new SimpleDateFormat(formatString);
        Date date = new Date();
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.add(c.DATE, -days);
        Date tempDate = c.getTime();
        String currentDayMinus = format.format(tempDate);
        return currentDayMinus;
    }
    /**
     * @Title: currentDayMinus
     * @Description: 根据系统参数对当前日期进行相加操作
     * @param formatString
     *            日期格式
     * @param days
     * @return String 当前日期相加后的日期
     */
    @SuppressWarnings("static-access")
    public static String currentDayAddition(int days, String formatString)
    {
        DateFormat format = new SimpleDateFormat(formatString);
        Date date = new Date();
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.add(c.DATE, +days);
        Date tempDate = c.getTime();
        String currentDayMinus = format.format(tempDate);
        return currentDayMinus;
    }
    /**
     * @Title: currentDayAdditionReturnDate
     * @Description: 当前日期加n天，返回Date类型
     * @param days
     * @return Date
     */
    public static Date currentDayAdditionReturnDate(Date date, int days)
    {
        // Date date = new Date();
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.add(Calendar.DATE, +days);
        Date tempDate = c.getTime();
        // String currentDayMinus = format.format(tempDate);
        return tempDate;
    }
    /**
     * @Title: currentSecondPlus
     * @Description: 对当前日期进行秒的加减运算
     * @param second
     *            与当前时间的差
     * @param formatString
     * @return String
     */
    @SuppressWarnings("static-access")
    public static String currentSecondPlus(int second, String formatString)
    {
        DateFormat format = new SimpleDateFormat(formatString);
        Date date = new Date();
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.add(c.SECOND, second);
        Date tempDate = c.getTime();
        String restul = format.format(tempDate);
        return restul;
    }
    /**
     * @Title: currentDateMinusMin
     * @Description: 当前日期
     * @param minutes
     * @return Date
     */
    public static Date currentDateMinusMin(int minutes)
    {
        Date date = new Date();
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.add(Calendar.MINUTE, -minutes);
        Date tempDate = c.getTime();
        return tempDate;
    }
    /**
     * @Title: getCurrentDate
     * @Description: 获取当前日期，不带时间
     * @return
     * @throws ParseException
     */
    public static Date getCurrentDate() throws ParseException
    {
        Date today = new Date();
        String todayStr = DateUtil.formatDate(today, "yyyy.MM.dd");
        Date currentDate = DateUtil.fromStringToDate("yyyy.MM.dd", todayStr);
        return currentDate;
    }
    /**
     * @Title: removeTimeInDate
     * @Description: 删除日期中的时间
     * @param date
     * @return Date
     * @throws ParseException
     */
    public static Date removeTimeInDate(Date date) throws ParseException
    {
        String dateStr = DateUtil.formatDate(date, "yyyy.MM.dd");
        Date newDate = DateUtil.fromStringToDate("yyyy.MM.dd", dateStr);
        return newDate;
    }
    /**
     * @Title: dateMinus
     * @Description: 两日期相减
     * @param endDate
     * @param currentDate
     * @return double
     */
    public static double dateMinus(Date endDate, Date currentDate)
    {
        double longTime = endDate.getTime() - currentDate.getTime();
        double day = longTime / 1000 / 60 / 60 / 24;
        return day;
    }
    /**
     * @Title: getCurrentDateTime
     * @Description: 获取当前时间
     * @return String
     */
    public static String getCurrentDateTime()
    {
        DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        return format.format(new Date());
    }
    /**
     * @Title: getCurrentDateStr
     * @Description: 获取当前日期串
     * @return
     */
    public static String getCurrentDateStr()
    {
        DateFormat format = new SimpleDateFormat("yyyy-MM-dd");
        return format.format(new Date());
    }
/**
     * @Title: getCurrentDateTime
     * @Description: 获取当前时间
     * @return String
     */
    public static String getCurrentDateTimeByFomat(String fomat)
    {
        DateFormat format = new SimpleDateFormat(fomat);
        return format.format(new Date());
    }
    /**
     * @Title: getFirstDayOfLastMonth
     * @Description: 获取某日期 前n个月的第一天
     * @return
     * @throws ParseException
     */
    public static Date getFirstDayOfLastMonth(Date date, int n)
            throws ParseException
    {
        // SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
        // 获取前月的第一天
        Calendar cal_1 = Calendar.getInstance();// 获取当前日期
        cal_1.setTime(date);
        cal_1.add(Calendar.MONTH, -n);
        cal_1.set(Calendar.DAY_OF_MONTH, 1);// 设置为1号,当前日期既为本月第一天
        Date result = cal_1.getTime();
        // String firstDay = format.format(cal_1.getTime());
        return removeTimeInDate(result);
    }
}