java日期操作

package net.app.utils;

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

public class DateUtil {

private static SimpleDateFormat mDateFormat;
private static Date mDate;
private static Calendar calendar;
public static final long SECONDS_OF_MINUTE = 60;
public static final long SECONDS_OF_HOUR = 60 * 60;
public static final long SECONDS_OF_DAY = 60 * 60 * 24;
public static final long DAYS_OF＿MONTH = 30;
public static final long DAYS_OF＿YEAR = 365;
public static final long MINUTES_OF_HOUR = 60;
public static final long MONTHES_OF_YEAR = 12;

/**
* 获取此时时间
*
* @param format
*            返回的时间格式
* @return
*/
public static String getNow(String format) {
mDate = new Date();
mDateFormat = new SimpleDateFormat(format);
return mDateFormat.format(mDate);
}

/**
* 格式化时间
*
* @param date
*            时间字符串
* @param dFomat
*            时间格式
* @param fomat
*            返回的时间格式
* @return
* @throws ParseException
*/
public static String format(String date, String dateFormat, String format)
throws ParseException {
mDate = getDate(date, dateFormat);
mDateFormat = new SimpleDateFormat(format);
return mDateFormat.format(mDate);
}

public static String format(Date date, String format){
mDateFormat = new SimpleDateFormat(format);
return mDateFormat.format(date);
}

/**
* 获取到date的时间秒
*
* @param date
* @param dateFormat
* @return
* @throws ParseException
*/
public static long getTime(String date, String dateFormat)
throws ParseException {
return getDate(date, dateFormat).getTime();
}

/**
* 获取到现在的时间秒
*
* @return
*/
public static long getTime() {
mDate = new Date();
return mDate.getTime();
}

public static int getYear() {
return Calendar.getInstance().get(Calendar.YEAR);
}

public static int getMonth() {
return Calendar.getInstance().get(Calendar.MONTH);
}

public static int getDayOfMonth() {
return Calendar.getInstance().get(Calendar.DAY_OF_MONTH);
}

public static int getDayOfYear() {
return Calendar.getInstance().get(Calendar.DAY_OF_YEAR);
}

public static int getHourOfDay() {
return Calendar.getInstance().get(Calendar.HOUR_OF_DAY);
}

public static int getMinute() {
return Calendar.getInstance().get(Calendar.MINUTE);
}

/**
* 获取时间与现在的时间差
*
* @param date
* @param format
* @return
* @throws ParseException
*/
public static String getHowLong(String date, String format)
throws ParseException {
String longTime = "";
calendar = Calendar.getInstance();
mDate = getDate(date, format);
Calendar calen = Calendar.getInstance();
calen.setTime(mDate);
int year = calen.get(Calendar.YEAR);
int month = calen.get(Calendar.MONTH);
int dayOfMonth = calen.get(Calendar.DAY_OF_MONTH);
int dayOfYear = calen.get(Calendar.DAY_OF_YEAR);
int hour = calen.get(Calendar.HOUR_OF_DAY);
int minute = calen.get(Calendar.MINUTE);
long days = getDays(calen);
if(days == 0){
if(getHourOfDay() - hour == 0){
if(getMinute() - minute == 0){
longTime = "刚刚";
}else {
longTime = (getMinute() - minute) + "分钟前";
}
}else {
if(getMinute()+(MINUTES_OF_HOUR-minute)+((getHourOfDay() - hour-1)*MINUTES_OF_HOUR) < MINUTES_OF_HOUR){
longTime = (getMinute()+(MINUTES_OF_HOUR-minute)) + "分钟前";
}else {
longTime = (getHourOfDay() - hour) + "小时前";
}
}
}else if(days < DAYS_OF＿MONTH){
longTime = days + "天前";
}else if(days < DAYS_OF＿YEAR && days >= DAYS_OF＿MONTH){
if(getYear() == year){
longTime = (getMonth() - month) + "个月前";
}else {
longTime = (getMonth() + (MONTHES_OF_YEAR - month)) + "个月前";
}

}else {
longTime = (getYear() - year) + "年前";
}
return longTime;
}

/**
*获取两个日期之间相差多少天
*/
public static int getDayBetween(String startTime,String todatTime){
SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
Calendar cal = Calendar.getInstance();
cal.setTime(sdf.parse(startTime));
long time1 = cal.getTimeInMillis();
cal.setTime(sdf.parse(todatTime));
long time2 = cal.getTimeInMillis();
//计算出相差月份是需要分清自然年
long between_days=(time2-time1)/(1000*3600*24);
return Integer.parseInt(between_days);
}

/**
* 获取距当前的天数
*
* @param calendar
* @return
*/
public static long getDays(Calendar calendar) {
long days = 0;
int year = calendar.get(Calendar.YEAR);
int dayOfYear = calendar.get(Calendar.DAY_OF_YEAR);
if (year == getYear()) {
days = getDayOfYear() - dayOfYear;
} else {
days = getDayOfYear()
+ (((getYear() - year - 1) * DAYS_OF＿YEAR) + (DAYS_OF＿YEAR - dayOfYear));
}
return days;
}

/**
* 获取时间
*
* @param date
* @param format
* @return
* @throws ParseException
*/
public static Date getDate(String date, String format)
throws ParseException {
mDateFormat = new SimpleDateFormat(format);
return mDateFormat.parse(date);
}
private final static ThreadLocal<SimpleDateFormat> dateFormater = new ThreadLocal<SimpleDateFormat>() {
@Override
protected SimpleDateFormat initialValue() {
return new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
}
};

private final static ThreadLocal<SimpleDateFormat> dateFormater2 = new ThreadLocal<SimpleDateFormat>() {
@Override
protected SimpleDateFormat initialValue() {
return new SimpleDateFormat("yyyy-MM-dd");
}
};
/**
* 将字符串转为日期类型
*
* @param sdate
* @return
*/
public static Date toDate(String sdate) {
try {
return dateFormater.get().parse(sdate);
} catch (ParseException e) {
return null;
}
}
/**
* 以友好的方式显示时间
*
* @param sdate
* @return
*/
public static String friendly_time(String sdate) {
Date time = null;
if (TimeZoneUtil.isInEasternEightZones()) {
time = toDate(sdate);
} else {
time = TimeZoneUtil.transformTime(toDate(sdate),
TimeZone.getTimeZone("GMT+08"), TimeZone.getDefault());
}
if (time == null) {
return "Unknown";
}
String ftime = "";
Calendar cal = Calendar.getInstance();

// 判断是否是同一天
String curDate = dateFormater2.get().format(cal.getTime());
String paramDate = dateFormater2.get().format(time);
if (curDate.equals(paramDate)) {
int hour = (int) ((cal.getTimeInMillis() - time.getTime()) / 3600000);
if (hour == 0)
ftime = Math.max(
(cal.getTimeInMillis() - time.getTime()) / 60000, 1)
+ "分钟前";
else
ftime = hour + "小时前";
return ftime;
}

long lt = time.getTime() / 86400000;
long ct = cal.getTimeInMillis() / 86400000;
int days = (int) (ct - lt);
if (days == 0) {
int hour = (int) ((cal.getTimeInMillis() - time.getTime()) / 3600000);
if (hour == 0)
ftime = Math.max(
(cal.getTimeInMillis() - time.getTime()) / 60000, 1)
+ "分钟前";
else
ftime = hour + "小时前";
} else if (days == 1) {
ftime = "昨天";
} else if (days == 2) {
ftime = "前天";
} else if (days > 2 && days <= 10) {
ftime = days + "天前";
} else if (days > 10) {
ftime = dateFormater2.get().format(time);
}
return ftime;
}
/**
* 获取当前是周几
* @return
*/
public static String getWeek(){
Calendar cal=Calendar.getInstance();
int i=cal.get(Calendar.DAY_OF_WEEK);
switch (i) {
case 1:
return "星期日";
case 2:
return "星期一";
case 3:
return "星期二";
case 4:
return "星期三";
case 5:
return "星期四";
case 6:
return "星期五";
case 7:
return "星期六";
default:
return "";
}
}
/**
* 根据日期获取星期
* @param date
* @return
*/
public static String getWeekofDate(Date date){
String[] weekDays = {"星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"};
Calendar cal = Calendar.getInstance();
cal.setTime(date);
int w = cal.get(Calendar.DAY_OF_WEEK) - 1;
if (w < 0)
w = 0;
return weekDays[w];
}
/**
* 返回指定日期前几天的日期
* @param date
* @param day
* @return
*/
public static String getDayBefore(Date date,int day){
Calendar now = Calendar.getInstance();
String format="yyyy-MM-dd";
mDateFormat=new SimpleDateFormat(format);
try {
date=mDateFormat.parse(getNow("dd"));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
now.setTime(date);
now.set(Calendar.DATE, now.get(Calendar.DATE) - day);
format="dd";
return mDateFormat.format(now.getTime()) ;
}
/**
* 返回指定日期后几天的日期
* @param date
* @param day
* @return
*/
public static String getDayAfter(Date date,int day){
Calendar now = Calendar.getInstance();
String format="yyyy-MM-dd";
mDateFormat=new SimpleDateFormat(format);
try {
date=mDateFormat.parse(getNow("dd"));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
now.setTime(date);
now.set(Calendar.DATE, now.get(Calendar.DATE) + day);
format="dd";
return mDateFormat.format( now.getTime());
}

/**
* 返回几天前的日期
* @param date
* @param day
* @return
*/
public static Date getDateBefore(Date date,int day){
Calendar now = Calendar.getInstance();
now.setTime(date);
now.set(Calendar.DATE, now.get(Calendar.DATE) - day);
return  now.getTime();
}
/**
* 返回几天后的日期
* @param date
* @param day
* @return
*/
public static Date getDateAfter(Date date,int day){
Calendar now = Calendar.getInstance();
now.setTime(date);
now.set(Calendar.DATE, now.get(Calendar.DATE) + day);
return  now.getTime();
}

}