java 日期做差 ： 场景 判断过期

public static String dateDiff(String startTime, String endTime,     
            String format) {     
        // 按照传入的格式生成一个simpledateformate对象     
        SimpleDateFormat sd = new SimpleDateFormat(format);     
        long nd = 1000 * 24 * 60 * 60;// 一天的毫秒数     
        long nh = 1000 * 60 * 60;// 一小时的毫秒数     
        long nm = 1000 * 60;// 一分钟的毫秒数     
        long ns = 1000;// 一秒钟的毫秒数     
        long diff;     
        long day = 0;     
        long hour = 0;     
        long min = 0;     
        long sec = 0;     
        // 获得两个时间的毫秒时间差异     
        try {     
            diff = sd.parse(endTime).getTime() - sd.parse(startTime).getTime();     
            day = diff / nd;// 计算差多少天     
            hour = diff % nd / nh + day * 24;// 计算差多少小时     
            min = diff % nd % nh / nm + day * 24 * 60;// 计算差多少分钟     
            sec = diff % nd % nh % nm / ns;// 计算差多少秒     
        } catch (ParseException e) {     
            e.printStackTrace();     
        }     
        return day + "天" + (hour - day * 24) + "小时"    
        + (min - day * 24 * 60) + "分钟";
    }  

分转换为小时天

    static String timeStamp(int  minute){
        String StatusMinute = "";
        int day= minute/60/24;
        int hour = minute/60%24;
        int min= minute % 60;
        if (day > 0)
        {
        StatusMinute= day + "天";
        } 
        if (hour>0)
        {
        StatusMinute += hour + "小时";
        } 
        if (min>0)
        {
         StatusMinute += min + "分钟";
        }
        System.out.println(StatusMinute);
        return StatusMinute;
        }

拆分数据：  

private List<Map<String, Object>> sqlitSql(List<String> str1,String originSql) {
        int step = 1000;
        int num = str1.size() / step;
        if (num > 0) {
            num++;
         }
        List<Map<String, Object>> parkLotList = new ArrayList<Map<String,Object>>();
        int n = 0;
        for(int i=1; i<=num;i++){
            StringBuilder str2 = new StringBuilder() ;
            for (int j=n;j<i*step;j++) {
                if(j==str1.size()){
                    break;
                }
                System.out.println("j+"+j);
                str2.append("'");
                str2.append(str1.get(j));
                str2.append("'");
                if(j!=i*step-1&&j!=str1.size()-1){
                    str2.append(",");
                }
            }
            String parkLotSql = originSql+str2 +") ";
            int nu = parkLotSql.length();
            List<Map<String, Object>> parkLotList1 = cgyJdbcTemplate.queryForList(parkLotSql);
            parkLotList.addAll(parkLotList1);
            n=i*step;
        }
        return parkLotList;
    }

生成6位不重复的随机字符：

public String getlinkNo() {
    String linkNo = "";
    // 用字符数组的方式随机
    String model = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
    char[] m = model.toCharArray();
    for (int j = 0; j < 6; j++) {
        char c = m[(int) (Math.random() * 36)];
        // 保证六位随机数之间没有重复的
        if (linkNo.contains(String.valueOf(c))) {
            j--;
            continue;
        }
        linkNo = linkNo + c;
    }
    return linkNo;
}