calendar|比较
import java.text.DateFormat; import java.util.*;

public class JspCalendar {     Calendar  calendar = null;

    public JspCalendar() {     calendar = Calendar.getInstance();     Date trialTime = new Date();     calendar.setTime(trialTime);     }

    public int getYear() {     return calendar.get(Calendar.YEAR);     }          public String getMonth() {     int m = getMonthInt();     String[] months = new String [] { "January", "February", "March",                     "April", "May", "June",                     "July", "August", "September",                     "October", "November", "December" };     if (m > 12)         return "Unknown to Man";          return months[m - 1];

    }

    public String getDay() {     int x = getDayOfWeek();     String[] days = new String[] {"Sunday", "Monday", "Tuesday", "Wednesday",                        "Thursday", "Friday", "Saturday"};

    if (x > 7)         return "Unknown to Man";

    return days[x - 1];

    }          public int getMonthInt() {     return 1 + calendar.get(Calendar.MONTH);     }

    public String getDate() {     return getMonthInt() + "/" + getDayOfMonth() + "/" +  getYear();

    }

    public String getTime() {     return getHour() + ":" + getMinute() + ":" + getSecond();     }

    public int getDayOfMonth() {     return calendar.get(Calendar.DAY_OF_MONTH);     }

    public int getDayOfYear() {     return calendar.get(Calendar.DAY_OF_YEAR);     }

    public int getWeekOfYear() {     return calendar.get(Calendar.WEEK_OF_YEAR);     }

    public int getWeekOfMonth() {     return calendar.get(Calendar.WEEK_OF_MONTH);     }

    public int getDayOfWeek() {     return calendar.get(Calendar.DAY_OF_WEEK);     }           public int getHour() {     return calendar.get(Calendar.HOUR_OF_DAY);     }          public int getMinute() {     return calendar.get(Calendar.MINUTE);     }

    public int getSecond() {     return calendar.get(Calendar.SECOND);     }

    public static void main(String args[]) {     JspCalendar db = new JspCalendar();     p("date: " + db.getDayOfMonth());     p("year: " + db.getYear());     p("month: " + db.getMonth());     p("time: " + db.getTime());     p("date: " + db.getDate());     p("Day: " + db.getDay());     p("DayOfYear: " + db.getDayOfYear());     p("WeekOfYear: " + db.getWeekOfYear());     p("era: " + db.getEra());     p("ampm: " + db.getAMPM());     p("DST: " + db.getDSTOffset());     p("ZONE Offset: " + db.getZoneOffset());     p("TIMEZONE: " + db.getUSTimeZone());     }

    private static void p(String x) {     System.out.println(x);     }

    public int getEra() {     return calendar.get(Calendar.ERA);     }

    public String getUSTimeZone() {     String[] zones = new String[] {"Hawaii", "Alaskan", "Pacific",                        "Mountain", "Central", "Eastern"};          return zones[10 + getZoneOffset()];     }

    public int getZoneOffset() {     return calendar.get(Calendar.ZONE_OFFSET)/(60*60*1000);     }

    public int getDSTOffset() {     return calendar.get(Calendar.DST_OFFSET)/(60*60*1000);     }

         public int getAMPM() {     return calendar.get(Calendar.AM_PM);     } }