Java中2个DATE类型求天数
//方法一Date[] d=new Date[2];d[0]=new Date("...");d[1]=new Date("...");Calendar[] cal=new Calendar[2];for(int i=0;i<cal.length;i++){cal[i]=Calendar.getInstance();cal[i].setTime(d[i]);cal[i].set(Calendar.HOUR_OF_DAY,0);cal[i].set(Calendar.MINUTE,0);cal[i].set(Calendar.SECOND,0);}long m=cal[0].getTime().getTime();long n=cal[1].getTime().getTime();int k=(int)Math.abs((m-n)/1000/3600/24);//方法二：public static int getDiffDays(String beginDate, String endDate)throws DefaultException{java.util.Date td1 = null;try {td1 = new SimpleDateFormat("yyyy-MM-dd").parse(beginDate);} catch (ParseException e1) {e1.printStackTrace();}long lBeginTime = td1.getTime();java.util.Date td2 = null;try {td2 = new SimpleDateFormat("yyyy-MM-dd").parse(endDate);System.out.println(td2);} catch (ParseException e) {e.printStackTrace();}long lEndTime = td2.getTime();int iDay = (int) ((lEndTime - lBeginTime) / 86400000);return iDay;//方法三import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Date;class Test2 { public static String getDate(){ SimpleDateFormat ft = new SimpleDateFormat("yyyy-MM-dd"); Date dd = new Date(); return ft.format(dd); } public static long getQuot(String time1, String time2){ long quot = 0; SimpleDateFormat ft = new SimpleDateFormat("yyyy-MM-dd"); try { Date date1 = ft.parse( time1 ); Date date2 = ft.parse( time2 ); quot = date1.getTime() - date2.getTime(); quot = quot / 1000 / 60 / 60 / 24; } catch (ParseException e) { e.printStackTrace(); } return quot; } public static void main(String[] args) throws Exception { String date1 = "2008-8-8"; String date2 = getDate(); long day = getQuot(date1,date2); System.out.println( "距离"+date1+" 还有 "+day+" 天" ); }} //java.text.SimpleDateFormat( "yyyy/MM/dd":String ) //++++ parse(String):Date ->ParseException //++++ format(Date):String **String格式为new SimpleDateFormat（String）参数格式//java.util.Date //++++ getTime():long **返回1970年1月1日之前之后的时刻（毫秒）//利用java.util.GregorianCalendar计算日期差（毫秒表示）import java.util.*;public class ElapsedMillis { public static void main(String[] args) { GregorianCalendar gc1 = new GregorianCalendar(1995, 11, 1, 3, 2, 1); GregorianCalendar gc2 = new GregorianCalendar(1995, 11, 1, 3, 2, 2); // the above two dates are one second apart Date d1 = gc1.getTime(); Date d2 = gc2.getTime(); long l1 = d1.getTime(); long l2 = d2.getTime(); long difference = l2 - l1; System.out.println("Elapsed milliseconds: " + difference); }}

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