A detailed explanation of the date in the Java string format

In actual development, some of the small partners will encounter some date processing problems, such as the date of comparison. Sometimes a date is not a date class, but rather a string representation, like this:1994-09-11, this date is not directly comparable, which requires us to format it first, where the DateFormat class.

First code:

The code is as follows

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public Boolean Comparedate (String startdate, String enddate) {     simpledateformat sdf = new SimpleDateFormat (" Yyyy-mm-dd ");     try {         Date sdate = Sdf.parse (startdate); & nbsp;       Date eDate = Sdf.parse (EndDate);         if (Edate.before (sdate)) {              return false;        } else {              return true;        }    } catch (ParseException e) {         e.printstacktrace ( );    }     return false; }

We do not use the DateFormat class, the SimpleDateFormat class, it is a subclass of the DateFormat class, this is not to say.

Look at the code, first construct a format object SDF, and then use SDF to format the input of the two string into a date, its format by the string you passed the decision, here is YYYY-MM-DD, because I want to pass the string is 1994-09-11 this format. Then use the SDF before method to compare the size of two dates, is not very convenient?

The most used in practice is the SimpleDateFormat class, and as a subclass of DateFormat, the SimpleDateFormat class obviously has more features than DateFormat, and he can format the standard date into the date format you want, Here is the sample code:

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Public String formatdate (date date) { SimpleDateFormat formater = new SimpleDateFormat ("YYYY year mm month DD Day"); To set up a template by constructing a method String datestring = Formater.format (date); Formater.applypattern ("yyyy.") Mm.dd ");//Reset Formatting template datestring = Formater.format (date); return datestring; }

Example

code is as follows

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Public class Timetest {     public static void Main (string[] args) { &NBSP;&NBSP;&NBSP;&NBSP;&N bsp;  //TODO auto-generated method stub         String str1= " 2015-02-08 20:20:20 ";         String str2= "2015-01-08 10:10:10";         int Res=str1.compareto (STR2);         if (res>0)              System.out.println ("str1>str2");         Else if (res==0)              System.out.println ("str1=str2");         Else              System.out.println ("str1<str2");        } }

Of course we can first try to check whether a string is not a valid date format

Example

The code is as follows

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public static Boolean isvaliddate (String str) { Boolean convertsuccess=true; Specify a date format of four-bit year/two-bit month/two-bit date, note that YYYY/MM/DD is case-sensitive; SimpleDateFormat format = new SimpleDateFormat ("Yyyy/mm/dd hh:mm"); try { Set lenient to False. Otherwise SimpleDateFormat will be more relaxed to verify the date, such as 2007/02/29 will be accepted and converted into 2007/03/01 Format.setlenient (FALSE); Format.parse (str); catch (ParseException e) { E.printstacktrace (); If throw java.text.ParseException or NullPointerException, the format is incorrect Convertsuccess=false; } return convertsuccess; }