guoln 发表于 2012-1-5 10:52:41

java中取得当月最后一天的四种方法


第一种,使用Calendar的roll方法,在限制某个日期字段不改变的形式下,改变其他日期字段的值。第二种,使用Calendar的getActualMaximum方法,取得指定日期字段的最大值。第三种,使用Calendar的set和add方法,从下个月的第一天计算得到以后月的最后一天。第四种,循环使用Calendar的add方法,加到本月的最后一天。以上四种方法如下示例:import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;public class DateTime { public static void main(String[] args) throws ParseException { DateTime dt = new DateTime(); Date date = new SimpleDateFormat("yyyy-MM-dd").parse("2008-02-14"); date = dt.lastDayOfMonth(date); System.out.println (new SimpleDateFormat("yyyy-MM-dd").format(date)); date = new SimpleDateFormat("yyyy-MM-dd").parse("2008-02-14"); date = dt.lastDayOfMonth2(date); System.out.println (new SimpleDateFormat("yyyy-MM-dd").format(date)); date = new SimpleDateFormat("yyyy-MM-dd").parse("2008-02-14"); date = dt.lastDayOfMonth3(date); System.out.println (new SimpleDateFormat("yyyy-MM-dd").format(date)); date = new SimpleDateFormat("yyyy-MM-dd").parse("2008-02-14"); date = dt.lastDayOfMonth4(date); System.out.println (new SimpleDateFormat("yyyy-MM-dd").format(date)); } public Date lastDayOfMonth(Date date) { Calendar cal = Calendar.getInstance(); cal.setTime(date); cal.set(Calendar.DAY_OF_MONTH, 1); cal.roll(Calendar.DAY_OF_MONTH, -1); return cal.getTime(); } public Date lastDayOfMonth2(Date date) { Calendar cal = Calendar.getInstance(); cal.setTime(date); int value = cal.getActualMaximum(Calendar.DAY_OF_MONTH); cal.set(Calendar.DAY_OF_MONTH, value); return cal.getTime(); } public Date lastDayOfMonth3(Date date) { Calendar cal = Calendar.getInstance(); cal.setTime(date); cal.set(Calendar.DAY_OF_MONTH, 1); cal.add(Calendar.MONTH, 1); cal.add(Calendar.DATE, -1); return cal.getTime(); } public Date lastDayOfMonth4(Date date) { Calendar cal = Calendar.getInstance(); cal.setTime(date); do { cal.1add(Calendar.DATE, 1); } while (cal.get(Calendar.DATE) != 1); cal.add(Calendar.DATE, -1); return cal.getTime(); } }输入日期:2008-02-14输入结果:2008-02-292008-02-292008-02-292008-02-29 原文链接:kin111.blog.51cto/738881/221672



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