Calender基本用法

不念不忘少年蓝@ 2022-05-22 05:27 183阅读 0赞

// 获取某日期的日号
    public int getDate(Date d) {
    Calendar ca = Calendar.getInstance();
    ca.setTime(d);
    int days = ca.get(Calendar.DATE);
    return days;
    }
    
    // 给定日期的前/后n天
    // n=-1表示前一天，n=1表示后一天
    public Date getDateForDayNum(Date date, int n) {
    Calendar ca = Calendar.getInstance();
    ca.setTime(date);
    ca.add(Calendar.DAY_OF_MONTH, n);
    Date d = ca.getTime();
    return d;
    }
    
    
    // 给定日期的前/后n月
    // n=-1表示前一月，n=1表示后一月
    public Date getDateForMonthNum(Date date, int n) {
    Calendar ca = Calendar.getInstance();
    ca.setTime(date);
    ca.add(Calendar.MONTH, n);
    Date d = ca.getTime();
    return d;
    }
    //前/后某月、前/后某日的日期
    public Date getDateForMonthNum(Date date, int Month,int day) {
    Calendar ca = Calendar.getInstance();
    ca.setTime(date);
    ca.add(Calendar.MONTH, Month);
    ca.add(Calendar.DAY_OF_MONTH, day);
    Date d = ca.getTime();
    return d;
    }
    
    // 给定日期的前/后n年
    // n=-1表示前一年，n=1表示后一年
    public Date getDateForYearNum(Date date, int n) {
    Calendar ca = Calendar.getInstance();
    ca.setTime(date);
    ca.add(Calendar.YEAR, n);
    Date d = ca.getTime();
    return d;
    }
    
    
    // 给定日期的前/后n小时
    // n=-1表示前一小时，n=1表示后一小时
    public Date getDateForHourNum(Date date, int n) {
    Calendar ca = Calendar.getInstance();
    ca.setTime(date);
    ca.add(Calendar.HOUR, n);
    Date d = ca.getTime();
    return d;
    }
    
    
    // 某年某月的最后一天
    public Date getLastDay(Date date) {
    Calendar ca = Calendar.getInstance();
    ca.setTime(date);
    ca.roll(Calendar.MONTH, 1);// 向后回滚一个月
    ca.set(Calendar.DATE, 0);
    Date time = ca.getTime();
    return time;
    }
    
    
    // 某年某月的有多少天
    public int getDateNumForDate(Date date) {
    Calendar ca = Calendar.getInstance();
    ca.setTime(date);
    ca.roll(Calendar.MONTH, 1);
    ca.set(Calendar.DATE, 0);
    return ca.get(Calendar.DATE);
    }
    
    
    // 某年某月是星期几（周日返回0，周一到周六就是1-6）
    public int getWeek(Date date) {
    Calendar ca = Calendar.getInstance();
    int week = ca.get(Calendar.DAY_OF_WEEK) - 1;// 设置
    return week;
    }