JAVA 时间差距，两个时间相差多少天，时，分，秒

方法一：获取天

 /*
    判读时间差距，两个时间相差多少天，时，分，秒
     */
    public static Long getDay(String date) {
        DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Long days = null;
        try {
            Date currentTime = dateFormat.parse(dateFormat.format(new Date()));//现在系统当前时间
            Date pastTime = dateFormat.parse(date);//过去时间
            long diff = currentTime.getTime() - pastTime.getTime();
            days = diff / (1000 * 60 * 60 * 24);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return days;
    }

方法二：获取  天，小时，分，秒

 public void test() {
        try {
            SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            Date now = df.parse("2019-03-26 13:31:40");//当前时间
            Date date = df.parse("2004-01-02 11:30:24");//过去
            long l = now.getTime() - date.getTime();
            long day = l / (24 * 60 * 60 * 1000);
            long hour = (l / (60 * 60 * 1000) - day * 24);
            long min = ((l / (60 * 1000)) - day * 24 * 60 - hour * 60);
            long s = (l / 1000 - day * 24 * 60 * 60 - hour * 60 * 60 - min * 60);
            System.out.println("" + day + "天" + hour + "小时" + min + "分" + s + "秒");
        } catch (Exception e) {

        }

    }

方法三：同上

 public void test() {
        try {
            SimpleDateFormat dfs = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            Date begin = dfs.parse("2004-01-02 11:30:24");
            Date end = dfs.parse("2004-03-26 13:31:40");
            long between = (end.getTime() - begin.getTime()) / 1000;//除以1000是为了转换成秒
            long day1 = between / (24 * 3600);
            long hour1 = between % (24 * 3600) / 3600;
            long minute1 = between % 3600 / 60;
            long second1 = between % 60 / 60;
            System.out.println("" + day1 + "天" + hour1 + "小时" + minute1 + "分" + second1 + "秒");
        } catch (Exception e) {

        }

    }

方法四：比较时间大小

 public void test() {
        String s1 = "2008-01-25 09:12:09";
        String s2 = "2008-01-29 09:12:11";
        java.text.DateFormat df = new java.text.SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        java.util.Calendar c1 = java.util.Calendar.getInstance();
        java.util.Calendar c2 = java.util.Calendar.getInstance();
        try {
            c1.setTime(df.parse(s1));
            c2.setTime(df.parse(s2));
        } catch (java.text.ParseException e) {
            System.err.println("格式不正确");
        }
        int result = c1.compareTo(c2);
        if (result == 0)
            System.out.println("c1相等c2");
        else if (result < 0)
            System.out.println("c1小于c2");
        else
            System.out.println("c1大于c2");
    }