java中怎么分别取得当前的年、月、日。

Question

②用getInstance方法
Calendar currentdate=Calendar.getInstance() ;
       long millissecond=currentdate.getTimeInMillis() ;
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    Calendar xmas = new GregorianCalendar(1998, Calendar.DECEMBER, 25);
    Calendar newyears = new GregorianCalendar(1999, Calendar.JANUARY, 1);    
    // Determine which is earlier
    boolean b = xmas.after(newyears);            // false
/*or */ b = xmas.before(newyears);                   // true    
    // Get difference in milliseconds
    long diffMillis = newyears.getTimeInMillis()-xmas.getTimeInMillis();    
    // Get difference in seconds
    long diffSecs = diffMillis/(1000);           // 604800    
    // Get difference in minutes
    long diffMins = diffMillis/(60*1000);        // 10080    
    // Get difference in hours
    long diffHours = diffMillis/(60*60*1000);    // 168    
    // Get difference in days
    long diffDays = diffMillis/(24*60*60*1000);  // 7

Answer 1

Calendar tempDate = Calendar.getInstance() ;
String monthFile = ""+(tempDate.get(Calendar.MONTH)+1);
String dayFile   = ""+tempDate.get(Calendar.DAY_OF_MONTH);
String yearFile  = ""+(tempDate.get(Calendar.YEAR));
String hourFile  = ""+tempDate.get(Calendar.HOUR_OF_DAY);//24-hour clock
String hourFile  = ""+tempDate.get(Calendar.HOUR);//12-hour clock
String minuteFile=""+tempDate.get(Calendar.MINUTE);