【Java】時(shí)間處理

xialong 發(fā)布于2019-08-14 11:49 / 514人閱讀

摘要：因?yàn)椋瑫?huì)按當(dāng)?shù)貢r(shí)區(qū)進(jìn)行解析，這時(shí)月份應(yīng)為中文的七月才能解析。時(shí)間運(yùn)算提供方法進(jìn)行運(yùn)算，第一個(gè)參數(shù)指明字段，第二個(gè)參數(shù)為。

當(dāng)前時(shí)間

Calendar cal = Calendar.getInstance();  //實(shí)例化
Date today = new Date(); //Date類的當(dāng)前時(shí)間

打印cal（類形式）

  java.util.GregorianCalendar[time=1406185232225,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=sun.util.calendar.ZoneInfo[id="Asia/Shanghai",offset=28800000,dstSavings=0,useDaylight=false,transitions=19,lastRule=null],firstDayOfWeek=1,minimalDaysInFirstWeek=1,ERA=1,YEAR=2014,MONTH=6,WEEK_OF_YEAR=30,WEEK_OF_MONTH=4,DAY_OF_MONTH=24,DAY_OF_YEAR=205,DAY_OF_WEEK=5,DAY_OF_WEEK_IN_MONTH=4,AM_PM=1,HOUR=3,HOUR_OF_DAY=15,MINUTE=0,SECOND=32,MILLISECOND=225,ZONE_OFFSET=28800000,DST_OFFSET=0]

獲取相應(yīng)字段

Date date = cal.getTime()  //當(dāng)前時(shí)間，Date對(duì)象
int year = cal.get(Calendar.YEAR); //獲取年份
int month = cal.get(Calendar.MONTH) + 1; //獲取月份，注意要從0開(kāi)始
int day = cal.get(Calendar.DATE);  //獲取天數(shù)

int hour = cal.get(Calendar.HOUR);
int minute = cal.get(Calendar.MINUTE);
int second = cal.get(Calendar.SECOND);

時(shí)間轉(zhuǎn)成String SimpleDateFormat

SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 
String todaytime = formatter.format(today);

DateFormatUtils

需要用到commons-lang-2.4.jar的包

DateFormatUtils.format(new Date(), "yyyy-MM-dd HH:mm:ss")

String轉(zhuǎn)成時(shí)間

不要忘了加Locale.CANADA，要不然月份Jul解析不了，會(huì)出現(xiàn)unparseable。因?yàn)椋瑂impleDateFormat會(huì)按當(dāng)?shù)貢r(shí)區(qū)進(jìn)行解析，這時(shí)月份應(yīng)為中文的七月才能解析。

String time = "05/Jul/2014:00:01:01";
Calendar cal = Calendar.getInstance();
SimpleDateFormat formatter = new SimpleDateFormat("dd/MMM/yyyy:HH:mm:ss", Locale.CANADA);
cal.setTime(formatter.parse(time));

時(shí)間運(yùn)算

Calendar提供add()方法進(jìn)行運(yùn)算，第一個(gè)參數(shù)指明字段，第二個(gè)參數(shù)為amount。要做減法，將amount置為負(fù)數(shù)即可。