Conversion and date type manipulation of Java string and date

String->date

String datestring = "2017-03-11"; Try {    new SimpleDateFormat ("Yyyy-mm-dd");     = Sdf.parse (datestring);} Catch (ParseException e) {    System.out.println (e.getmessage ());}

/*** String conversion to TIME format *@paramDatestr the string to be converted *@paramFormatstr Example of a target string requiring formatting Yyyy-mm-dd *@returndate returns the converted time *@throwsparseexception Conversion Exception*/    PrivateDate parsedate (String Strformat, String dateValue) {if(DateValue = =NULL)            return NULL; if(Strformat = =NULL) Strformat= "YyyyMMdd"; DateFormat DateFormat=NewSimpleDateFormat (Strformat); Date Date=NULL; Try{Date=Dateformat.parse (DateValue); } Catch(parseexception pe) {date=NULL; }        returndate; }

Importjava.text.ParseException;ImportJava.text.SimpleDateFormat;ImportJava.util.Calendar;Importjava.util.Date;Importorg.apache.commons.lang.StringUtils;/*** Date Util class * *@authorYK*/ Public classdateutil{Private StaticString Defaultdatepattern = "Yyyy-mm-dd"; /*** Get the default date pattern*/     Public StaticString Getdatepattern () {returnDefaultdatepattern; }    /*** Returns the current date string for the preset format*/     Public StaticString Gettoday () {Date today=NewDate (); returnformat (today); }    /*** Formatting date into strings using preset format*/     Public StaticString Format (date date) {returnDate = =NULL? " ": Format (date, Getdatepattern ()); }    /*** Format date into a string using the parameter formats*/     Public Staticstring Format (date date, string pattern) {returnDate = =NULL? " " :NewSimpleDateFormat (pattern). Format (date); }    /*** Convert a string to date using a preset format*/     Public StaticDate Parse (String strdate)throwsParseException {returnStringutils.isblank (strdate)?NULL: Parse (strdate, Getdatepattern ()); }    /*** Use parameter format to convert a string to date*/     Public StaticDate Parse (string strdate, string pattern)throwsParseException {returnStringutils.isblank (strdate)?NULL:NewSimpleDateFormat (pattern). Parse (strdate); }    /*** Add a few months to the date*/     Public StaticDate Addmonth (date date,intN) {Calendar cal=calendar.getinstance ();        Cal.settime (date);        Cal.add (Calendar.month, N); returnCal.gettime (); }     Public Staticstring Getlastdayofmonth (string year, string month) {Calendar cal=calendar.getinstance (); //yearsCal.set (Calendar.year, Integer.parseint (year)); //month, because the calendar month is starting from 0, so to 1//Cal.set (Calendar.month, Integer.parseint (MONTH)-1); //Day, set to a numberCal.set (Calendar.date, 1); //month plus one, get a number next monthCal.add (Calendar.month, 1); //next one months minus one last day of the monthCal.add (Calendar.date, 1); returnString.valueof (Cal.get (calendar.day_of_month));//What's the date of the month    }     Public StaticDate GetDate (string year, string month, String day)throwsparseexception {String result= year + "-" + (month.length () = = 1? ("0" + month): month) + "-" + (day.length () = = 1? ("0" +Day) : day); returnparse (result); }}

Date->string

/**      * Date Turn string     *      @param  count     @return*/           @SuppressWarnings ("unused")    private  String datetostring ( Date date) {        return (new SimpleDateFormat ("YyyyMMdd")). Format (date);    

PrivateDate AddDays (date date,intN) {Calendar cal=calendar.getinstance ();          Cal.settime (date); //Cal.add (calendar.date, n);//N is the increase in the number of days that can be changedCal.add (Calendar.day_of_year, N);//hours plus 1Date =Cal.gettime (); returndate; }        /*** A string that returns the day of the week based on a date *@paramDate *@return      */     PrivateString Getweek (date date) {Calendar C=calendar.getinstance ();          C.settime (date); //int Hour=c.get (calendar.day_of_week); //The hour is the day of the week, its range 1~7//1 = Sunday 7= Saturday, other analogy          return NewSimpleDateFormat ("Eeee"). Format (C.gettime ()); }

Conversion and date type manipulation of Java string and date