java日期处理类

开发中常常要使用日期，先小结如下，以备后用。

import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;public class FormatTime {private final static SimpleDateFormat sdf=new SimpleDateFormat("yyyyMMdd");private final static SimpleDateFormat sdfymdhm = new SimpleDateFormat("yyyyMMddHHmmss");private final static SimpleDateFormat sdfymdhms =   new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");/** * * @Title: getCurrentDay * @Description: TODO 获取当天时间(20161109)* @return */public static String getCurrentDay(){return sdf.format(new Date());}/** * * @Title: fTime2 * @Description: TODO 获取time这个日期以前dayAgo天的日期* @return */public static String fTime(String time,int dayAgo){Date date = null;        try {            date = sdf.parse(time);        } catch (ParseException e) {throw new RuntimeException(e);       }Calendar calendar = Calendar.getInstance();calendar.setTime(date);if(dayAgo>0){calendar.add(Calendar.DAY_OF_MONTH, -dayAgo);//前15天数据date = calendar.getTime();calendar.setTime(date);}int year=calendar.get(Calendar.YEAR);  int month=calendar.get(Calendar.MONTH) + 1;  int day = calendar.get(Calendar.DAY_OF_MONTH); String mon="";String d="";if(month<10){mon="0"+month;}else{mon=month+"";}if(day<10){d="0"+day;}else{d=""+day;}String ret=year+""+mon+""+d;return ret;}/** * * @Title: fTime2 * @Description: TODO 获取time这个日期以后dayAfter天的日期* @return */public static String fTime2(String time,int dayAfter){Date date = null;        try {            date = sdf.parse(time);        } catch (ParseException e) {throw new RuntimeException(e);       }Calendar calendar = Calendar.getInstance();calendar.setTime(date);if(dayAfter>0){calendar.add(Calendar.DAY_OF_MONTH, +dayAfter);//后15天数据date = calendar.getTime();calendar.setTime(date);}int year=calendar.get(Calendar.YEAR);  int month=calendar.get(Calendar.MONTH) + 1;  int day = calendar.get(Calendar.DAY_OF_MONTH); String mon="";String d="";if(month<10){mon="0"+month;}else{mon=month+"";}if(day<10){d="0"+day;}else{d=""+day;}String ret=year+""+mon+""+d;return ret;}/** * * @Title: getDefaultTime * @Description: TODO 获取昨天的日期* @return */public static String getDefaultTime(){Calendar calendar = Calendar.getInstance();calendar.add(Calendar.DAY_OF_MONTH, -1);//前1天Date date = calendar.getTime();String time=sdf.format(date);return time;}/** * * @Title: getSunday * @Description: TODO 获取最近一个星期天* @return */public static String getSunday(){SimpleDateFormat f = new SimpleDateFormat("yyyyMMdd");        Calendar c = Calendar.getInstance();        c.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);        return f.format(c.getTime());}/** * * @Title: getMonthFirstDay * @Description: TODO 获取本月第一天* @return */public static String getCurrentMonthFirstDay(){    Calendar   cal_1=Calendar.getInstance();//获取当前日期        cal_1.add(Calendar.MONTH, 0);        cal_1.set(Calendar.DAY_OF_MONTH,1);//设置为1号,当前日期既为本月第一天        String  firstDay = sdf.format(cal_1.getTime());return firstDay;}/** * * @Title: getMonthFirstDay * @Description: TODO 获取上月第一天* @return */public static String getPreviousMonthFirstDay(){ //获取当前月第一天：    Calendar c = Calendar.getInstance();       c.add(Calendar.MONTH, -1);    c.set(Calendar.DAY_OF_MONTH,1);//设置为1号,当前日期既为本月第一天    String first = sdf.format(c.getTime());    return first;}/** * * @Title: getMonthFirstDay * @Description: TODO 获取上月最后一天* @return */public static String getPreviousMonthLastDay(){    //获取当前月最后一天    Calendar ca = Calendar.getInstance();       ca.set(Calendar.DAY_OF_MONTH,0);//    String lastDay = sdf.format(ca.getTime());    return lastDay;}/** * * @Title: getCurrentMonthLastDay * @Description: TODO 获取指定时间最后一天* @return */public static String getCurrentMonthLastDay(String time){Date date =null;  try {date= sdf.parse(time);} catch (ParseException e) {// TODO Auto-generated catch blocke.printStackTrace();}    //获取当前月最后一天    Calendar ca = Calendar.getInstance();    ca.setTime(date);    ca.set(Calendar.DAY_OF_MONTH,     ca.getActualMaximum(Calendar.DAY_OF_MONTH)); //    String lastDay = sdf.format(ca.getTime());    return lastDay;}/*** * * @Title: getCurrentWeekDay * @Description: TODO 获取本周周一 */    public static String getCurrentMonday(){     Calendar cal = Calendar.getInstance();     cal.setFirstDayOfWeek(Calendar.MONDAY);//将每周第一天设为星期一，默认是星期天     cal.add(Calendar.DATE, 0);     cal.set(Calendar.DAY_OF_WEEK,Calendar.MONDAY);      String monday = sdf.format(cal.getTime());      return monday;    }        /*** * * @Title: getPreviousSunday * @Description: TODO 获取上周周日 */    public static String getPreviousSunday(){     Calendar cal = Calendar.getInstance();      cal.setFirstDayOfWeek(Calendar.MONDAY);//将每周第一天设为星期一，默认是星期天      cal.add(Calendar.DATE, -1*7);      cal.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);     String sunday =sdf.format(cal.getTime());     return sunday;    }        /**     *     * @Title: getMiniSencond     * @Description: TODO 将日期转换为毫秒数    * @param str    * @return     */public static String getMiniSencond(String str){long millionSeconds=0;try {millionSeconds = sdfymdhm.parse(str).getTime();//毫秒} catch (ParseException e) {// TODO Auto-generated catch blocke.printStackTrace();}return millionSeconds+"";} /**     *     * @Title: getDateSencond     * @Description: TODO 将日期转换为毫秒数    * @param str    * @return     */public static long getDateSencond(String str){long millionSeconds=0;try {millionSeconds = sdfymdhms.parse(str).getTime();//毫秒} catch (ParseException e) {// TODO Auto-generated catch blocke.printStackTrace();}return millionSeconds;}/** * 计算日期相差天数 * @param str1 * @param str2 * @return */public static int getDistanceOfTwoDate(String str1,String str2){int result=0;try{Date date1 = sdf.parse(str1);Date date2 =sdf.parse(str2);    Calendar aCalendar = Calendar.getInstance();       aCalendar.setTime(date1);       int day1 = aCalendar.get(Calendar.DAY_OF_YEAR);       aCalendar.setTime(date2);       int day2 = aCalendar.get(Calendar.DAY_OF_YEAR);       result = day1-day2;}catch(Exception e){e.printStackTrace();}return result;}/** * * @Title: long2Date * @Description: TODO long 转日期(年-月-日 时-分-秒)* @param timestamp* @return */public static String longToDate(Long msecond){Date date = new Date(msecond);return sdfymdhms.format(date);}