获取指定日期的第一天和最后一天

package com.tczxg.date;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
 *
 * @author Zhao,XingGuo
 * @version 1.0 build in 2009-12-09 实现了指定日期的第一天和最后一天的获取
 *
 */
public class FirstAndLastDay {

 /**
  *
  * @param reg
  * @param date
  * @return a string
  */
 public static String dateFormat(String reg, Date date) {
  SimpleDateFormat sdf = new SimpleDateFormat(reg);
  return sdf.format(date);
 }

 public static String getMonthFirstDay(Date date) {
  Calendar calendar = Calendar.getInstance();
  calendar.setTime(date);
  calendar.set(Calendar.DAY_OF_MONTH, calendar
    .getActualMinimum(Calendar.DAY_OF_MONTH));
  return dateFormat("yyyy-MM-dd", calendar.getTime());

 }

 public static String getMonthLastDay(Date date) {
  Calendar calendar = Calendar.getInstance();
  calendar.setTime(date);
  calendar.set(Calendar.DAY_OF_MONTH, calendar
    .getActualMaximum(Calendar.DAY_OF_MONTH));
  return dateFormat("yyyy-MM-dd", calendar.getTime());
 }

 /**
  * @param args
  * @deprecated 不检查警告
  */
 public static void main(String[] args) {
  Date date = new Date();
  //5 就是 6 月
  date.setMonth(5);
  System.out.println(FirstAndLastDay.getMonthFirstDay(date));
  System.out.println(FirstAndLastDay.getMonthLastDay(date));

 }

}