java常用操作方法（一）日期工具类 DateUtil

/*
* Created on 2011-5-26
*
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*/
/********************************************************
*  Copyright (C)
*  File name:      // 文件名
*  Author:         // 作者
*  Date:          
*  Description:    // 详细说明此程序文件完成的主要功能
*  Others:         // 其它内容的说明
*  History:
*    1. Date:           // 修改日期
*       Author:         // 作者
*       Modification:  
********************************************************/
package com.jinqiao.util;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import javax.persistence.Entity;

/**
* @author jason
*
* To change the template for this generated type comment go to
* Window>Preferences>Java>Code Generation>Code and Comments
*/
@Entity
public class DateUtil {


public static String yyyy_MM_dd = "yyyy-MM-dd";
public static String yyyyMMdd = "yyyyMMdd";
public static String yyyyMM = "yyyyMM";
public static String yyyy_MM = "yyyy-MM";
public static String yyyy_MM_dd_HH_mm = "yyyy-MM-dd HH:mm";
public static String yyyyMMddHHmm = "yyyyMMddHHmm";
public static String yyyyMMddHHmmss = "yyyyMMddHHmmss";
public static String yyyy_MM_dd_HH_mm_ss = "yyyy-MM-dd HH:mm:ss";


/**
* 将字符串时间改成Date类型
* @param format
* @param dateStr
* @return
*/
public  static Date strToDate(String format,String dateStr) {

Date date = null;

try {
SimpleDateFormat simpleDateFormat = new SimpleDateFormat(format);
date = simpleDateFormat.parse(dateStr);
} catch (ParseException e) {
e.printStackTrace();
}

return date;
}


/**
* 将Date时间转成字符串
* @param format
* @param date
* @return
*/
public static String DateToStr(String format,Date date){

SimpleDateFormat simpleDateFormat = new SimpleDateFormat(format);

return simpleDateFormat.format(date);
}



/**
* 获取2个字符日期的天数差
* @param p_startDate
* @param p_endDate
* @return 天数差
*/
public static long getDaysOfTowDiffDate( String p_startDate, String p_endDate ){
 
Date l_startDate = DateUtil.strToDate(DateUtil.yyyy_MM_dd, p_startDate);
Date l_endDate = DateUtil.strToDate(DateUtil.yyyy_MM_dd, p_endDate);
long l_startTime = l_startDate.getTime();
long l_endTime = l_endDate.getTime();
long betweenDays = (long) ( ( l_endTime - l_startTime ) / ( 1000 * 60 * 60 * 24 ) );
return betweenDays;
}


/**
* 获取2个Date型日期的分钟数差值
* @param p_startDate
* @param p_endDate
* @return 分钟数差值
*/
public static long getMinutesOfTowDiffDate( Date p_startDate, Date p_endDate ){
 
long l_startTime = p_startDate.getTime();
long l_endTime = p_endDate.getTime();
long betweenMinutes = (long) ( ( l_endTime - l_startTime ) / ( 1000 * 60 ) );
return betweenMinutes;
}

/**
* 获取2个字符日期的天数差
* @param p_startDate
* @param p_endDate
* @return 天数差
*/
public static long getDaysOfTowDiffDate( Date l_startDate, Date l_endDate ){
 
long l_startTime = l_startDate.getTime();
long l_endTime = l_endDate.getTime();
long betweenDays = (long) ( ( l_endTime - l_startTime ) / ( 1000 * 60 * 60 * 24 ) );
return betweenDays;
}


/**
* 给出日期添加一段时间后的日期
* @param dateStr
* @param plus
* @return
*/
public static String getPlusDays(String format,String dateStr,long plus){

Date date = DateUtil.strToDate(format, dateStr);

long time = date.getTime()+ plus*24*60*60*1000;


return DateUtil.DateToStr(format,new Date(time));
}


/**
* 给出日期添加一段时间后的日期
* @param dateStr
* @param plus
* @return
*/
public static String getPlusDays(String format,Date date,long plus){


long time = date.getTime()+ plus*24*60*60*1000;


return DateUtil.DateToStr(format,new Date(time));
}
}