Java时间处理方法

//获得下周一的日期
public Date getNextMonday(Date date){
Calendar cal = Calendar.getInstance();  
cal.setTime(getThisWeekTuesday(date));  
cal.add(Calendar.DATE, 6);  
return cal.getTime();
}
//获得上周二的日期
public Date getLastWeekTuesday(Date date) {
Calendar cal = Calendar.getInstance();
cal.setTime(getThisWeekTuesday(date));
cal.add(Calendar.DATE, -7);
return cal.getTime();

    }

//获得当前周周二的日期

    public Date getThisWeekTuesday(Date date) {  

        Calendar cal = Calendar.getInstance();  

        cal.setTime(date);  

        // 获得当前日期是一个星期的第几天  

        int dayWeek = cal.get(Calendar.DAY_OF_WEEK);  

        if (1 == dayWeek) {  

            cal.add(Calendar.DAY_OF_MONTH, -1);  

        }  

        // 设置一个星期的第一天，按中国的习惯一个星期的第一天是星期一  

        cal.setFirstDayOfWeek(Calendar.MONDAY);  

        // 获得当前日期是一个星期的第几天  

        int day = cal.get(Calendar.DAY_OF_WEEK) - 1;  

        // 根据日历的规则，给当前日期减去星期几与一个星期第一天的差值  

        cal.add(Calendar.DATE, cal.getFirstDayOfWeek() - day);  

        return cal.getTime();

    }

    
//判断当前日期是周几
public int getDayOfWeek(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
if(calendar.get(Calendar.DAY_OF_WEEK) - 1 == 0){
return Calendar.DAY_OF_WEEK;
} else {
return calendar.get(Calendar.DAY_OF_WEEK) - 1;
}
    }

/* public static void main(String[] args) throws Exception {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date date = sdf.parse("2018-02-03");
DateTime dateTime = new DateTime(date);
int dayOfWeek = dateTime.getDayOfWeek()-1;
int weekyear = dateTime.weekyear().get();
System.out.println("一周的第"+dayOfWeek+"天");
System.out.println(weekyear);
}*/
public static void main(String[] args) throws ParseException {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date date = sdf.parse("2018-01-03");
Calendar cale = Calendar.getInstance();
cale.setTime(date);

        cale.add(Calendar.MONTH, 1);

        cale.set(Calendar.DAY_OF_MONTH, 0);

        String lastDay = sdf.format(cale.getTime());

        System.out.println("下月最后一天是 ： " + lastDay);
}