Calendar和Date都没用提供能直接计算两个日期之间时间间隔的api，所以使用了在java8后提供的java.time包下的Duration类来实现,需要先将Date转成java8提供的java.time.LocalDateTime，然后再使用Duration计算两个时间之间的间隔。代码如下：
 
public String createResponseDurationStr(Date startTime, Date endTime) {
        Calendar
        StringBuilder sb = null;
        if (startTime != null && endTime != null){
            Instant startInstant = startTime.toInstant();
            Instant endInstant = endTime.toInstant();
            ZoneId zoneId = ZoneId.systemDefault();
            LocalDateTime start = startInstant.atZone(zoneId).toLocalDateTime();
            LocalDateTime end = endInstant.atZone(zoneId).toLocalDateTime();
            long days = Duration.between(start,end).toDays();
            long hours = Duration.between(start, end).toHours();
            long minutes = Duration.between(start, end).toMinutes();
            if (days > 0){
                sb = new StringBuilder("");
                sb.append(days).append("天");
            }
            if (hours >= 0){
                sb = sb ==  null ? new StringBuilder("") : sb;
                if (sb.length() > 0 || hours != 0){
                    sb.append(hours).append("小时");
                }
            }
            if (minutes > 0){
                sb = sb ==  null ? new StringBuilder("") : sb;
                sb.append(minutes).append("分钟");
            }
            if (sb != null && sb.length() > 0){
                sb.insert(0,"响应时长: ");
            }
        }
        return sb == null ?  null : sb.toString();
    }
 
返回示例：
 
响应时长：1小时5分钟

    public Long getWorkTime(Date startDate, Date endDate) {
        String start = DateFormatUtils.format(startDate.getTime(), "yyyy-MM-dd");
        String end = DateFormatUtils.format(endDate.getTime(), "yyyy-MM-dd");
        /**
         * 由数据库配置表中查出
         * 特殊的工作日(星期六、日工作)
         */
        List<String> specialWorkDays = this.baseMapper.selectSpecialWorkDays(start, end);
        /**
         * 由数据库配置表中查出
         * 特殊的休息日(星期一到五休息)
         */
        List<String> specialRestDays = this.baseMapper.selectSpecialRestDays(start, end);
        
        
        return getworkTime(start, end, specialWorkDays, specialRestDays, startDate, endDate);
    }

    private Long getworkTime(String strStartDate, String strEndDate, List<String> specialWorkDays, List<String> specialRestDays, Date startDate, Date endDate) {

        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd");

        Calendar cl1 = Calendar.getInstance();
        Calendar cl2 = Calendar.getInstance();

        try {
            cl1.setTime(df.parse(strStartDate));
            cl2.setTime(df.parse(strEndDate));

        } catch (ParseException e) {
            System.out.println("日期格式非法");
            e.printStackTrace();
        }

        // 休息日天数
        int count = 0;
        while (cl1.compareTo(cl2) <= 0) {
            //如果是周六或者周日则休息日+1
            if (cl1.get(Calendar.DAY_OF_WEEK) == 7 || cl1.get(Calendar.DAY_OF_WEEK) == 1) {
                count++;
                //如果是周六或者周日，但是该日属于需要工作的日子则 -1
                if (specialWorkDays.contains(DateFormatUtils.format(cl1.getTime(), "yyyy-MM-dd"))) {
                    count--;
                }
            }
            //如果不是周六或者周日，但是该日属于国家法定节假日或者特殊放假日则+1
            if (specialRestDays.contains(DateFormatUtils.format(cl1.getTime(), "yyyy-MM-dd"))) {
                count++;
            }
            cl1.add(Calendar.DAY_OF_MONTH, 1);
        }

        Long time= endDate.getTime() - startDate.getTime();

        time = time - (count * 1000 * 60 * 60 * 24L);

        return time;
    }

/**
 * 计算两个日期之间相差的天数
 */
public static int daysBetween(Date sendDate, Date startDate) {
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    try {
        sendDate = sdf.parse(sdf.format(sendDate));
        startDate = sdf.parse(sdf.format(startDate));
    } catch (Exception e) {
        e.printStackTrace();
    }
    Calendar cal = Calendar.getInstance();
    cal.setTime(sendDate);
    long time1 = cal.getTimeInMillis();
    cal.setTime(startDate);
    long time2 = cal.getTimeInMillis();
    long between_days = (time2 - time1) / (1000 * 3600 * 24);
    return Integer.parseInt(String.valueOf(between_days));
}

 
 

 
 
 
 
 
 import java.text.DateFormat;
 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Scanner;
 
 

 public class DateDemo
 {
  
  
  public static void main(String [] args) throws ParseException
  {
   
   
   Scanner in = new Scanner(System.in);
   System.out.println("请输入第一个日期（格式为:年-月-日）：");
   String date1 = in.nextLine();
   System.out.println("请输入第二个日期（格式为:年-月-日）：");
   String date2 = in.nextLine();
   
      test(date1,date2);
   
  }
 //  用来计算两个日期之间相差的毫秒数
  public static void test(String date1,String date2) throws ParseException
    {
   DateFormat df = DateFormat.getDateInstance();
   df= new SimpleDateFormat("yyyy-MM-dd");
   
   Date date_1 = df.parse(date1);
   Date date_2 = df.parse(date2);
   
   long time1 = date_1.getTime();
   long time2 = date_2.getTime();
   long time3 = Math.abs(time1-time2);
   
   int day = getDay(time3);
      System.out.println("两日期相隔"+day+"天");
    }
 //将两个日期之间的毫秒数换算成天数
  private static int getDay(long time)
  {
   int day = (int)(time/1000/60/60/24);
   return day;
  }
 }