java 日期的工具类_java 日期时间工具类

packageorg.apache.pwd.util;

importjava.text.SimpleDateFormat;

importjava.util.Calendar;

importjava.util.Date;

publicclassDateFormatUtil{

/**12小时制*/

privatestaticfinalStringDATE_FORMAT_12_HOUR="yyyy/MM/ddhh:mm:ss";

/**24小时制*/

privatestaticfinalStringDATE_FORMAT_24_HOUR="yyyy/MM/ddHH:mm:ss";

/**

*根据格式返回日期字符串

*

*@paramdateInfo

*日期

*@paramstringFormat

*格式化字符串

*@return日期字符串

*/

publicstaticStringgetStringDate(DatedateInfo,StringstringFormat){

if(isNullOrEmpty(stringFormat)){

returnnull;

}

SimpleDateFormatsdf=newSimpleDateFormat(stringFormat);

Stringformated=sdf.format(dateInfo);

returnformated;

}

/**

*根据格式返回日期

*

*@paramdateInfo

*日期字符串

*@paramstringFormat

*格式化字符串

*@return日期

*@throwsException

*例外

*/

publicstaticDategetFormatDate(StringdateInfo,StringstringFormat)throwsException{

if(isNullOrEmpty(stringFormat)){

returnnull;

}

SimpleDateFormatsdf=newSimpleDateFormat(stringFormat);

Dateformated=sdf.parse(dateInfo);

returnformated;

}

/**

*根据年月日生成Calendar对象

*

*@paramyear

*年

*@parammonth

*月

*@paramday

*日

*@returnCalendar对象

*/

publicstaticCalendarcreateCalendar(intyear,intmonth,intday){

Calendarcal=Calendar.getInstance();

if(year

year=2000+year;

}

cal.set(year,month-1,day);

returncal;

}

/**

*根据日期生成Calendar对象

*

*@paramdate

*日期

*@returnCalendar对象

*/

publicstaticCalendarcreateCalendar(intdate){

intyear=date/1000;

intmonth=(date%10000)/100;

intday=date%100;

Calendarcal=Calendar.getInstance();

cal.set(year,month-1,day);

returncal;

}

/**

*返回年份

*

*@return年份

*@throwsException

*例外

*/

publicstaticIntegergetNowYear()throwsException{

Calendarcal=Calendar.getInstance();

intyear=cal.get(Calendar.YEAR);

returnyear;

}

/**

*返回月份

*

*@return月份

*@throwsException

*例外

*/

publicstaticIntegergetNowMonth()throwsException{

Calendarcal=Calendar.getInstance();

intmonth=cal.get(Calendar.MONTH)+1;

returnmonth;

}

/**

*返回当前日期

*

*@return日期

*/

publicstaticIntegergetNowDay(){

Calendarcal=Calendar.getInstance();

intday=cal.get(Calendar.DAY_OF_MONTH);

returnday;

}

/**

*返回某月份的第一天

*

*@paramyear

*年

*@parammonth

*月

*@return某月份的第一天

*/

publicstaticIntegergetFirstDayOfMonth(intyear,intmonth){

Calendarcal=createCalendar(year,month,1);

intday=cal.get(Calendar.DAY_OF_MONTH);

returnday;

}

/**

*返回某月份的最后一天

*

*@paramyear

*年

*@parammonth

*月

*@return某月份的最后一天

*/

publicstaticIntegergetLastDayOfMonth(intyear,intmonth){

Calendarcal=createCalendar(year,month,1);

intlastDay=cal.getActualMaximum(Calendar.DAY_OF_MONTH);

returnlastDay;

}

/**

*计算两个日期之间相差的天数

*

*@paramstartDate

*开始日期

*@paramendDate

*结束日期

*@return两个日期之间相差的天数

*/

publicstaticIntegerdaysBetweenData(IntegerstartDate,IntegerendDate){

if(startDate==null||endDate==null){

returnnull;

}

CalendarstartCal=createCalendar(startDate);

CalendarendCal=createCalendar(endDate);

Calendarcal=null;

if(startCal.before(endCal)){

cal=startCal;

startCal=endCal;

endCal=cal;

}

Longlg=(startCal.getTimeInMillis()-endCal.getTimeInMillis())/1000/60/60/24;

returnlg.intValue();

}

/**

*判断是否为闰年

*

*@paramobj

*输入年份

*@return是否为闰年

*@throwsException

*例外

*/

publicstaticbooleanisLeapYear(Tobj)throwsException{

SimpleDateFormatsdf=newSimpleDateFormat("yyyy/MM/dd");

Calendarcalendar=Calendar.getInstance();

intyear=0;

if(objinstanceofString){

DatedateInfo=sdf.parse((String)obj);

calendar.setTime(dateInfo);

year=calendar.get(Calendar.YEAR);

}elseif(objinstanceofDate){

calendar.setTime((Date)obj);

year=calendar.get(Calendar.YEAR);

}else{

returnfalse;

}

if((year%4==0&&year%100!=0)||(year%100==0&&year%400==0)){

System.out.println("是闰年");

returntrue;

}

System.out.println("不是闰年");

returnfalse;

}

/**

*

*

*@paramstringFormat

*@return

*/

publicstaticbooleanisNullOrEmpty(StringstringFormat){

return(stringFormat==null||stringFormat.length()==0)?true:false;

}

publicstaticvoidmain(String[]args)throwsException{

StringdateInfo="/12/12";

Calendarcal=Calendar.getInstance();

cal.setTime(newSimpleDateFormat("yyyy/MM/dd").parse(dateInfo));

//isLeapYear(cal.getTime());

System.out.println(getNowDay());

System.out.println(getFirstDayOfMonth(,12));

System.out.println(getLastDayOfMonth(,9));

//System.out.println(getStringDate(newDate(),"yyyy/MM/ddHH:mm:ss"));

System.out.println(daysBetweenData(0303,0304));

}

}