java操作当前日期的年月日

我就是我 2022-08-18 08:18 704阅读 0赞

**java获取当前日期的年月日：**

Calendar calendar = Calendar.getInstance();  
    calendar.setTime(new Date());
    System.out.println("年: " + calendar.get(Calendar.YEAR));  
    System.out.println("月: " + (calendar.get(Calendar.MONTH) + 1) + "");  
    System.out.println("日: " + calendar.get(Calendar.DAY_OF_MONTH));  
    System.out.println("时: " + calendar.get(Calendar.HOUR_OF_DAY));  
    System.out.println("分: " + calendar.get(Calendar.MINUTE));  
    System.out.println("秒: " + calendar.get(Calendar.SECOND));  
    System.out.println("当前时间毫秒数：" + calendar.getTimeInMillis());  
    System.out.println(calendar.getTime());

**java获取两个日期之间的所有月份：**  
（timelineStr数组中存放从开始时间到结束时间内的所有月份）

Calendar startDateCalendar = Calendar.getInstance();
    startDateCalendar.setTime(startDate);//startDate为Date类型
    int start = startDateCalendar.get(Calendar.MONTH) + 1;
    String startMouth = (startDateCalendar.get(Calendar.MONTH) + 1) + "月";// 开始时间所处的月份
    
    Calendar endDateCalendar = Calendar.getInstance();
    endDateCalendar.setTime(endDate);//endDate为Date类型
    int end = endDateCalendar.get(Calendar.MONTH) + 1;
    String endMouth = (endDateCalendar.get(Calendar.MONTH) + 1) + "月";// 结束时间所处的月份
    
    
    int mouths = end - start;
    String timelineStr = new String[]{mouths};
    for (int j = 0; j <= mouths; j++) {
        timelineStr[i]=startMouth;
        startDateCalendar.add(Calendar.MONTH, 1); // 设置为后一月
        startMouth = (startDateCalendar.get(Calendar.MONTH) + 1) + "月";
    }

**java获取两个日期之间的每一月的所有天（如1月1号-1月31号）：**

String[] categoryStr = {};
    //存放从开始时间到结束时间内的所有月份的天数
    List<List<String>> categoryMDList = new ArrayList<List<String>>();
    
    Calendar startDateCalendar = Calendar.getInstance(Locale.CHINA);
    startDateCalendar.setTime(startDate);//startDate为Date类型
    int start = startDateCalendar.get(Calendar.MONTH) + 1;
    String startMouth = (startDateCalendar.get(Calendar.MONTH) + 1) + "月";// 开始时间所处的月份
    
    Calendar endDateCalendar = Calendar.getInstance(Locale.CHINA);
    endDateCalendar.setTime(endDate);//endDate为日期类型
    int end = endDateCalendar.get(Calendar.MONTH) + 1;
    String endMouth = (endDateCalendar.get(Calendar.MONTH) + 1) + "月";// 结束时间所处的月份
    
    int flag = end - start;
    for (int j = 0; j <= flag; j++) {
        List<String> category = new ArrayList<String>();
        int day = startDateCalendar.getActualMaximum(Calendar.DATE);// 获取当前月份的天数
        categoryStr = new String[day];
        //categoryStr中存放数据数量为当前月份的天数，格式X月x号
        for (int i = 0; i < categoryStr.length; i++) {
            categoryStr[i] = String.valueOf(start) + "月" + String.valueOf(i + 1) + "号";
        }
        category.addAll(Arrays.asList(categoryStr));
        categoryMDList.add(category);
    
        startDateCalendar.add(Calendar.MONTH, 1); // 设置为后一月
        start ++;
    }

**java获取当前时间前一个小时的时间：**

Calendar calendar = Calendar.getInstance();　
    /* HOUR_OF_DAY 指示一天中的小时 */
    calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY) - 1);　
    SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");　
    System.out.println("一个小时前的时间：" + df.format(calendar.getTime()));　
    System.out.println("当前的时间：" + df.format(new Date()));

输出：

一个小时前的时间：  2015-12-16 15:34:33
    当前的时间：  2015-12-16 16:34:33