Date的常用工具类

package com.cmcc.flow.common.util;

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

public class DateUtil {
/**
*
* @Title:compare_date
* @Description: 比较两个日期的先后顺序
* @param dt1
* @param dt2
* @return
* 0: dt1== dt2
* 1: dt1>dt2
* -1: dt1<dt2
* 其它值: 比较结果无效
* @throws
*/
public static int compare_date(Date dt1,Date dt2){
if(dt1==null || dt2==null)
{
return -2;
}

if (dt1.getTime() > dt2.getTime()) {//dt1 在 dt2后
return 1;
} else if (dt1.getTime() < dt2.getTime()) {//dt1在dt2前
return -1;
} else {
return 0;//dt1=dt2
}
}

/**
*
* @Title: getChineseYMD
* @Description: date得到中文的年月日
* @param HttpServletRequest request，Model model
* @return String
*/
public static String getChineseYMD(Date date){
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy年MM月dd日");
return dateFormat.format(date);
}

public static Date converStrToDate(String format, String date) throws ParseException {
Date dateTemp = null;
SimpleDateFormat formater2 = new SimpleDateFormat(format);
dateTemp = formater2.parse(date);
return dateTemp;
}

public static Date getBeginMonthOfDate(Date date) throws ParseException{
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM");
String dateStr = dateFormat.format(date);
dateStr += "-01";
return converStrToDate("yyyy-MM-dd", dateStr);
}

/**
* 获取当月月初
* @throws ParseException
*/
public static Date getAfterFewMonths(Date date, int fewMonths) throws ParseException{
date = getBeginMonthOfDate(date);
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
calendar.add(Calendar.MONTH, fewMonths);
return calendar.getTime();
}
}