java中对日期的处理

日期和时间模式

[java] view
plaincopyprint?





// 格式：年－月－日 小时：分钟：秒

public static final String FORMAT_ONE = "yyyy-MM-dd HH:mm:ss";

// 格式：年－月－日 小时：分钟

public static final String FORMAT_TWO = "yyyy-MM-dd HH:mm";

// 格式：年月日 小时分钟秒

public static final String FORMAT_THREE = "yyyyMMdd-HHmmss";

// 格式：年－月－日

public static final String FORMAT_FOUR = "yyyy-MM-dd";

// 格式：年月日

public static final String FORMAT_FOUR_NO = "yyyyMMdd";

// 格式：年－月

public static final String FORMAT_FIVE = "yyyy-MM";

// 格式：年月

public static final String FORMAT_SIX = "yyyyMM";

static final String dayNames[] = { "星期日", "星期一", "星期二", "星期三", "星期四","星期五", "星期六" };

private static final SimpleDateFormat timeFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

yyyyMMdd 转换为 yyyy-MM-dd

[java] view
plaincopyprint?





public static String stringTostring(String str){

SimpleDateFormat sf1 = new SimpleDateFormat(FORMAT_FOUR_NO);

SimpleDateFormat sf2 =new SimpleDateFormat(FORMAT_FOUR);

String sfstr = "";

try

{

sfstr = sf2.format(sf1.parse(str));

}

catch (Exception e) {

e.printStackTrace();

}

return sfstr;

}

把符合日期格式的字符串转换为日期类型

[java] view
plaincopyprint?





public static java.util.Date stringtoDate(String dateStr, String format)

{

Date d = null;

SimpleDateFormat formater = new SimpleDateFormat(format);

try

{

formater.setLenient(false);//指定日期\时间解析是否不严格

d = formater.parse(dateStr);

}

catch (Exception e)

{

e.printStackTrace();

}

return d;

}

把日期类型转换为字符串

[java] view
plaincopyprint?





public static String dateToString(java.util.Date date, String format)

{

String result = "";

SimpleDateFormat formater = new SimpleDateFormat(format);

try

{

result = formater.format(date);

}

catch (Exception e)

{

e.printStackTrace();

}

return result;

}

对某个日期进行处理相加减

[java] view
plaincopyprint?





/**

* @param dateKind 指定处理年、月、日

* @param dateStr 指定日期

* @param amount 指定长度

* @return

*/

public static String dateSub(int dateKind, String dateStr, int amount)

{

Date date = stringtoDate(dateStr, FORMAT_ONE);

Calendar calendar = Calendar.getInstance();

calendar.setTime(date);

calendar.add(dateKind, amount);

return dateToString(calendar.getTime(), FORMAT_ONE);

}

返回一个相加减后的日期 yyyy-MM-dd

[java] view
plaincopyprint?





public static String dateSub(int days)

{

Calendar calendar = Calendar.getInstance();

calendar.add(Calendar.DAY_OF_YEAR, days);

return dateToString(calendar.getTime(), FORMAT_FOUR);

}

两个日期相减得到的秒数

[java] view
plaincopyprint?





public static long timeSub(String firstTime, String secTime)

{

long first = stringtoDate(firstTime, FORMAT_ONE).getTime();

long second = stringtoDate(secTime, FORMAT_ONE).getTime();

return (second - first) / 1000;

}

获取某年某月的天数 Method1

[java] view
plaincopyprint?





public static int getDaysOfMonth(String year, String month)

{

Date date = stringtoDate(year+"-"+month, FORMAT_FIVE);

Calendar calendar = Calendar.getInstance();

calendar.setTime(date);

return calendar.getActualMaximum(Calendar.DAY_OF_MONTH);

}

获取某年某月的天数 Method2

[java] view
plaincopyprint?





public static int getDaysOfMonth(int year, int month)

{

Calendar calendar = Calendar.getInstance();

calendar.set(year, month - 1, 1);

return calendar.getActualMaximum(Calendar.DAY_OF_MONTH);

}

返回日期的年

[java] view
plaincopyprint?





public static int getYear(Date date)

{

Calendar calendar = Calendar.getInstance();

calendar.setTime(date);

return calendar.get(Calendar.YEAR);

}

返回当前年份

[java] view
plaincopyprint?





public static int getTodayYear()

{

return getYear(new Date());

}

返回日期的月份，1-12

[java] view
plaincopyprint?





public static int getMonth(Date date)

{

Calendar calendar = Calendar.getInstance();

calendar.setTime(date);

return calendar.get(Calendar.MONTH) + 1;

}

返回当前月份

[java] view
plaincopyprint?





public static int getTodayMonth()

{

return getMonth(new Date());

}

计算两个日期相差的天数，如果date2 > date1 返回正数，否则返回负数

[java] view
plaincopyprint?





public static long dayDiff(Date date1, Date date2)

{

return (date2.getTime() - date1.getTime()) / 86400000;

}

获取当前日期字符串，格式"yyyy-MM-dd HH:mm:ss"

[java] view
plaincopyprint?





public static String getNow()

{

Calendar today = Calendar.getInstance();

return dateToString(today.getTime(), FORMAT_ONE);

}

获取当前时间的指定格式

[java] view
plaincopyprint?





public static String getCurrDate(String format)

{

return dateToString(new Date(), format);

}

判断日期是否有效,包括闰年的情况

[java] view
plaincopyprint?





public static boolean isDate(String date)

{

StringBuffer reg = new StringBuffer(

"^((\\d{2}(([02468][048])|([13579][26]))-?((((0?");

reg.append("[13578])|(1[02]))-?((0?[1-9])|([1-2][0-9])|(3[01])))");

reg.append("|(((0?[469])|(11))-?((0?[1-9])|([1-2][0-9])|(30)))|");

reg.append("(0?2-?((0?[1-9])|([1-2][0-9])))))|(\\d{2}(([02468][12");

reg.append("35679])|([13579][01345789]))-?((((0?[13578])|(1[02]))");

reg.append("-?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))");

reg.append("-?((0?[1-9])|([1-2][0-9])|(30)))|(0?2-?((0?[");

reg.append("1-9])|(1[0-9])|(2[0-8]))))))");

Pattern p = Pattern.compile(reg.toString());

return p.matcher(date).matches();

}