Java中的时间工具类有哪些

Java中的时间工具类有哪些？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。

具体如下：

package org.zhy.date;import java.text.DateFORMat;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;import java.util.GreGorianCalendar;public class DateUtils {  // 时间格式定义  public static final String DATE_PATTERN_YYYY_MM_DD = "yyyy-MM-dd"; // 2011-10-09  public static final String yyyyMMddhhmmss = "yyyyMMddhhmmss";// 20111009100155  public static final String yyyy_MM_ddhhMMss = "yyyy-MM-dd hh:MM:ss";// 2011-10-09  // 10:01:55  // 时间格式：年月日时分秒  public static final int YEAR = 1;// 年  public static final int MONTH = 2;// 月  public static final int DAY = 3; // 日  public static final int HOUROFDAY = 4;// 时  public static final int MINUTE = 5;// 分  public static final int SECOND = 6;// 秒    public static String DateToString(java.util.Date date, String date_fomat) {    DateFormat df = new SimpleDateFormat(date_fomat);    return df.format(date);  }    public static Date stringToDate(int year, int month, int dayOfMonth,      int hourOfDay, int minute, int second) {    GregorianCalendar GC = new GregorianCalendar(year, month, dayOfMonth,        hourOfDay, minute, second);    Date dt = gc.getTime();    return dt;  }    public static Date stringToDate(int year, int month, int dayOfMonth) {    GregorianCalendar gc = new GregorianCalendar(year, month, dayOfMonth);    Date dt = gc.getTime();    return dt;  }    public static boolean isLeapYear(Date date) {    GregorianCalendar gc = gcToDate(date);    return gc.isLeapYear(findYearByDate(date, YEAR));  }    public static int findYearByDate(Date date, int type) {    Calendar cd = Calendar.getInstance();    cd.setTime(date);    int number=0;    switch (type) {      case YEAR :        number= cd.get(Calendar.YEAR);        break;      case MONTH :        number= cd.get(Calendar.MONTH);        break;      case DAY :        number= cd.get(Calendar.DAY_OF_MONTH);        break;      case HOUROFDAY :        number= cd.get(Calendar.HOUR_OF_DAY);        break;      case MINUTE :        number= cd.get(Calendar.MINUTE);        break;      case SECOND :        number= cd.get(Calendar.SECOND);        break;      default :        number= 0;    }    return number;  }    private static GregorianCalendar gcToDate(Date date) {    GregorianCalendar gc = new GregorianCalendar();    gc.setTime(date);    return gc;  }}