Java on time (date) essay!

/**
* Get System Current time
* @return System Current Time
*/
public static Date now () {
return new Date ();
}

/**
* Based on the date specified, get its relative days before date
* eg:data=2013-09-09
* days = 3
* Return to =2013-09-06
* Dates specified @param date
* @param days relative to day
* @return Date
*/
public static date Getdatebefore (date date, int days) {
if (date = = null)
Date = Now ();
Calendar now = Calendar.getinstance ();
Now.settime (date);
Now.set (Calendar.date, Now.get (calendar.date)-days);
return Now.gettime ();
}

/**
* Gets the date relative to the number of months months, based on the specified date
* eg:data=2013-09-09
* Month = 1
* Return to =2013-08-10
* Dates specified @param date
* @param months relative number of months
* @return Date
*/
public static date Getdatebeforemonth (date date, int months) {
if (date = = null)
Date = Now ();
Calendar now = Calendar.getinstance ();
Now.settime (date);
Now.set (Calendar.month, Now.get (calendar.month)-months);
return Now.gettime ();
}

/**
* The date after which the relative number of months is months based on the specified date
* eg:data=2013-09-09
* Month = 1
* Return to =2013-10-10
* Dates specified @param date
* @param months relative number of months
* @return Date
*/
public static date Getdateaftermonth (date date, int months) {
if (date = = null)
Date = Now ();
Calendar now = Calendar.getinstance ();
Now.settime (date);
Now.set (Calendar.month, Now.get (calendar.month) + months);
return Now.gettime ();
}

/**
* Based on the date specified, get its date after days
* eg:data=2013-09-09
* days = 3
* Return to =2013-09-12
* Dates specified @param date
* @param days relative to day
* @return Date
*/
public static date Getdateafter (date date, int days) {
if (date = = null)
Date = Now ();
Calendar now = Calendar.getinstance ();
Now.settime (date);
Now.set (Calendar.date, Now.get (calendar.date) + days);
return Now.gettime ();
}

/**
* Based on the specified date, the date after which the relative number of years years is obtained
* eg:data=2013-09-09
* Month = 1
* Return to =2014-09-08
* Dates specified @param date
* @param year relative number of years
* @return Date
*/
public static date Getdateafteryear (date date, int year) {
if (date = = null)
Date = Now ();
Calendar now = Calendar.getinstance ();
Now.settime (date);
Now.set (Calendar.year, Now.get (calendar.year) + year);
return Now.gettime ();
}

public static string GetDate (date date, string format) {
if (date = = null)
Date = Now ();
return new SimpleDateFormat (format). format (date);
}

public static string Getcurrentdate (string format) {
Return GetDate (New Date (), format);
}

public static String Getcurrentdate () {
Return Getcurrentdate ("Yyyy-mm-dd");
}

/**
* Custom formatting time
*
* @param date Time
* @param formatstr formatted string, default MM/DD/YYYY
* @return formatted time string
*/
public static string formartdate (date date, string formatstr) {
if (date = = null)
Date = Now ();
if (Stringutil.isempty (FORMATSTR)) {
Formatstr = "mm/dd/yyyy";
}
SimpleDateFormat sdf = new SimpleDateFormat (FORMATSTR);
return Sdf.format (date);
}

/**
* Convert a time format character to a time type
* @param datestr string with time format
* @param pattern format string
* @return Post-conversion time type data
*/
public static Date formdate (String datestr,string pattern) {
SimpleDateFormat SDF = new SimpleDateFormat (pattern);
Date date = null;
try {
Date = Sdf.parse (DATESTR);
} catch (ParseException e) {
E.printstacktrace ();
}
return date;
}

/**
* Get start time of the day
*
* @return
*/
public static Date GetStartTime () {
Calendar Todaystart = Calendar.getinstance ();
Todaystart.set (calendar.hour, 0);
Todaystart.set (calendar.minute, 0);
Todaystart.set (Calendar.second, 0);
Todaystart.set (Calendar.millisecond, 0);

return Todaystart.gettime ();
}

/**
* Get the day end time
*
* @return
*/
public static Date Getendtime () {
Calendar todayend = Calendar.getinstance ();
Todayend.set (Calendar.year, 4028);
Todayend.set (Calendar.hour_of_day, 23);
Todayend.set (Calendar.minute, 59);
Todayend.set (Calendar.second, 59);
Todayend.set (Calendar.millisecond, 999);
return Todayend.gettime ();
}

/**
* Comparison of two time difference
* @param start time
* @param end time
* @return Two time difference
* @throws ParseException
*/

public static long Timecompare (Date start,date end) {
Calendar Acalendar = Calendar.getinstance ();

Acalendar.settime (start);

int day1 = Acalendar.get (calendar.day_of_year);

Acalendar.settime (end);

int day2 = Acalendar.get (calendar.day_of_year);

return day2-day1;

}

/**
* Comparison of two time sizes
* @param start
* @param end
* @return End-start > 0 true, otherwise false
*/
public static Boolean compare (Date Start,date end) {
Calendar Acalendar = Calendar.getinstance ();

Acalendar.settime (start);

int day1 = Acalendar.get (calendar.day_of_year);

Acalendar.settime (end);

int day2 = Acalendar.get (calendar.day_of_year);

Return day2-day1 >= 0? True:false;

}

public static int GetYear () {
Calendar a=calendar.getinstance ();
Return A.get (calendar.year);
}
public static int GetMonth () {
Calendar a=calendar.getinstance ();
Return A.get (calendar.month) +1;
}
public static int GetDate () {
Calendar a=calendar.getinstance ();
Return A.get (calendar.date);
}



/**
* Get the first day of the year
* @param year
* @return
*/
public static Date Getyearfirst () {
Calendar ca=calendar.getinstance ();
int year = Ca.get (calendar.year);

Ca.clear ();
Ca.set (Calendar.year, year);
Date Yearfirst = Ca.gettime ();
return yearfirst;
}


/**
* Get the last day of the year
* @param year
* @return
*/
public static Date Getyearlast () {
Calendar ca=calendar.getinstance ();
int year = Ca.get (calendar.year);

Ca.clear ();
Ca.set (Calendar.year, year);
Ca.roll (Calendar.day_of_year,-1);

Date yearlast = Ca.gettime ();

return yearlast;

}


public static void Main (string[] args) {
String str1 = "2014-02-20";
String str2 = "2014-12-20";
list<string> Listb = new arraylist<string> ();
list<string> Liste = new arraylist<string> ();
Listb.add ("2014-01-01");
Liste.add ("2014-12-30");

System.out.println (Insertvalidate (str1, str2, Listb, Liste));

}

/**
* Judgment Time Cross
* @param begindate
* @param endDate
* @param begindatelist
* @param enddatelist
* @return False Cross, true, not cross.
*/
public static Boolean insertvalidate (String begindate,string enddate,list<string> begindatelist,list<string > Enddatelist) {
Integer begin = Trimchar (begindate);
Integer end = Trimchar (endDate);
list<integer> beginList = new arraylist<integer> ();
list<integer> endlist = new arraylist<integer> ();
for (int i = 0; i < begindatelist.size (); i++) {
Beginlist.add (Trimchar (Begindatelist.get (i)));
Endlist.add (Trimchar (Enddatelist.get (i)));//A start time corresponds to an end time
}

for (int i = 0; i < endlist.size (); i + +) {
if (Begin < Endlist.get (i) && end > Beginlist.get (i)) {
return false; Overlap exists
}
}

return true;
}

public static Integer Trimchar (String str) {
String year = str.substring (0,4);
String Yue = str.substring (5,7);
String ri = str.substring (8,10);
String newstring = Year+yue+ri;
System.out.println (newstring);
Return Integer.parseint (newstring);
}

Java on time (date) essay!