DateUtil

我们要使用StringUtil工具类,所以首先导入;

            org.apache.commons
            commons-lang3
            3.1
 	

import java.sql.Timestamp;
import java.text.SimpleDateFormat;
import java.util.*;


public class DateUtil {
    
    public static final String DEFAULT_DATE_FORMAT = "yyyy-MM-dd";
    
    public static final String DEFAULT_TIME_FORMAT = "HH:mm:ss";
    
    public static final String DEFAULT_DATE_TIME_FORMAT = "yyyy-MM-dd HH:mm:ss";
    
    public static final String CN_DATE_FORMAT = "yyyy年MM月dd日";

//   1. 时间转换String
    
    public static String dateToString(Date date, String pattern) {
        SimpleDateFormat sdf = new SimpleDateFormat(pattern);
        return sdf.format(date);
    }
    
    public static String dateToString(long date ,String pattern){
        SimpleDateFormat sdf = new SimpleDateFormat(pattern);
        Date nowDate = new Date(date * 1000);
        return sdf.format(nowDate);
    }

//    2. String转时间
    
    public static Date StringToDate(String date ,String pattern){
        SimpleDateFormat sdf = new SimpleDateFormat(pattern);
        Date nowDate = new Date();
        try{
            nowDate =  sdf.parse(date);
        } catch (Exception e){
            e.printStackTrace();
        }
        return nowDate;
    }

    
    public static long StringToUnixLong(String date){
        Date nowDate = StringToDate(date, "");
        Timestamp timestamp = new Timestamp(nowDate.getTime());
        return timestamp.getTime() / 1000;
    }
//    3. 获取当前时间
    
    public static String getDate(String pattern){
        SimpleDateFormat sdf = new SimpleDateFormat(pattern);
        return  sdf.format(new Date());
    }

    
    public static long getUnixLong(){
        return System.currentTimeMillis();
    }

// 4. 日期计算
    // 4.1 日期分割算法 - 根据指定天数进行分割
    public static List> splitDateList (String startDateStr, String endDateStr, int dayNum, String pattern) throws Exception{
        SimpleDateFormat df = new SimpleDateFormat(pattern);
        if(dayNum < 1){ return null; }
        List> dateList = new ArrayList>();
        //时间转换
        Date startDate = df.parse(startDateStr);
        Date endDate = df.parse(endDateStr);
        //创建日历
        Calendar cal = Calendar.getInstance();
        //设置时间
        cal.setTime(startDate);
        while(true){
            Map dateMap = new HashMap();
            //遍历设置天数
            cal.add(Calendar.DATE, dayNum-1);
            if(cal.getTime().getTime() < endDate.getTime()){
                dateMap.put("startDate", df.format(startDate));
                dateMap.put("endDate", df.format(cal.getTime()));
                dateList.add(dateMap);
            }else{
                dateMap.put("startDate", df.format(startDate));
                dateMap.put("endDate", df.format(endDate));
                dateList.add(dateMap);
                break;
            }
            //重新设置天数
            cal.add(Calendar.DATE, 1);
            startDate = cal.getTime();
        }
        return dateList;
    }




}