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));

}

}