本文介紹了獲取長日期,短日期,年,月,周等日期處理的基本方法。
import org.springframework.stereotype.Component;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
/**
* date util
*/
@Component
public final class DateUtil {
/**
* 獲取長日期
* return yyyy-MM-dd HH:mm:ss
*/
public static String getLongDateString() {
Date date = new Date();
SimpleDateFormat dateformat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String dateStr = dateformat.format(date);
return dateStr;
}
/**
* 獲取短日期
* return yyyy-MM-dd
*/
public static String getShortDateString() {
Date date = new Date();
SimpleDateFormat dateformat = new SimpleDateFormat("yyyy-MM-dd");
String dateStr = dateformat.format(date);
return dateStr;
}
/**
* 獲取本週自然周次
* return yyyyww
*/
public static Integer getNowWeek() {
Calendar c = Calendar.getInstance();
int week = c.get(Calendar.WEEK_OF_YEAR);//獲取是本年的第幾周
int year = c.get(Calendar.YEAR);//獲取年份
return year*100+week;
}
/**
* 獲取當前月份字符串,帶年
* @return 201607 string
*/
public static String getCurrentMonth() {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMM");
return dateFormat.format(new Date());
}
/**
* 獲取當前年份
*
* @return 201607 string
*/
public static String getCurrentYear() {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy");
return dateFormat.format(new Date());
}
/**
* 判斷當前日期是星期幾
* 1,2,3,4,5,6,7 週一到週日
* @param pTime 要判斷的時間
* @return dayForWeek 判斷結果
* @Exception 發生異常
*/
public static Integer dayForWeek(String pTime) throws ParseException {
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
Calendar c = Calendar.getInstance();
c.setTime(format.parse(pTime));
int dayForWeek = 0;
if(c.get(Calendar.DAY_OF_WEEK) == 1){
dayForWeek = 7;
}else{
dayForWeek = c.get(Calendar.DAY_OF_WEEK) - 1;
}
return dayForWeek;
}
/**
* 獲取當前日期上一天的字符串,具體到某月某日
* @return 20160705 string
*/
public static String getLastDate() {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMdd"); //yyyyMMdd
long times = System.currentTimeMillis()-86400000;
return dateFormat.format(new Date(times));
}
/**
* 獲取當前日期前/後n天的日期的字符串,具體到某月某日
* @param n n爲正表示今天之後的n天,n爲負數表示今天之前的n天,n爲0表示今天。
* @return 20160705 string
*/
public static String getSpecificDate(int n) {
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMdd"); //yyyyMMdd
long times = System.currentTimeMillis()+86400000*n;
return dateFormat.format(new Date(times));
}
/**獲取間隔天數*/
public static String getIntervalDays(String endDate,String startDate){
if(endDate==null||startDate==null){
return null;
}
try
{
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date firstDate = sdf.parse(endDate);
Date secondDate = sdf.parse(startDate);
//得到兩個日期對象的總毫秒數
long firstDateMilliSeconds = firstDate.getTime();
long secondDateMilliSeconds = secondDate.getTime();
//得到兩者之差
long MinusSecond = firstDateMilliSeconds - secondDateMilliSeconds;
//得到總天數
String days = String.valueOf( MinusSecond / (1000*3600*24));
return days;
}
catch (ParseException e)
{
System.out.println(e.getMessage());
}
return null;
}
/**
* 獲取月份, 0:當月, -1:上月, -2:上上月, ...; 1:下月, 2:下下月, ...
* @param num
* @return eg. 201608
*/
public static String getCurrentMonth(int num) {
if(num == 0)
return getCurrentMonth();
else
return addMonth(getCurrentMonth(), num);
}
/**
* @param currentMonth 201607
* @return 201608
*/
public static String nextMonth(String currentMonth) {
return addMonth(currentMonth, 1);
}
/**
* @param currentMonth 201607
* @return 201606
*/
public static String lastMonth(String currentMonth) {
return addMonth(currentMonth, -1);
}
/**
* @param monthStr 201607
* @param num 增加的月數, 負值就是減少, eg:1
* @return 201608 string
*/
public static String addMonth(String monthStr, int num) {
Calendar cal = Calendar.getInstance();
cal.set(Calendar.YEAR, Integer.parseInt(monthStr.substring(0, 4)));
cal.set(Calendar.MONTH, Integer.parseInt(monthStr.substring(4)) - 1);
cal.add(Calendar.MONTH, num);
return cal.get(Calendar.YEAR) + String.format("%02d", cal.get(Calendar.MONTH) + 1);
}
/**
* 時間比較, 返回 1:timeStr1在timeStr2之前, 0:時間相等, -1:timeStr1在timeStr2之後
* @param timeStr1
* @param timeStr2
* @return int
*/
public static int timeBefore(String timeStr1, String timeStr2) {
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
try{
long time1 = format.parse(timeStr1).getTime();
long time2 = format.parse(timeStr2).getTime();
if (time1 < time2){
return 1;
} else if (time1 == time2) {
return 0;
} else {
return -1;
}
}catch(Exception e){
log.error("exception:",e);
}
return -1;
}
/**
* 根據日期獲取自然周次: 注意:本方法以周天開頭
* @param nowTime
* @return 201951 (2019年51周)
*/
public static String getNatureWeek(String nowTime) {
SimpleDateFormat dateFormatter = new SimpleDateFormat("yyyy-MM-dd");
Date date=null;
try {
date = dateFormatter.parse(nowTime);
} catch (java.text.ParseException e) {
log.error("error{}",e);
}
dateFormatter.applyPattern("yw");
return dateFormatter.format(date);
}
}