日期字符串与Date日期的相互转换

1、字符串转日期

//字符串转日期
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date dt = null;
        try {
            dt = (("dt").toString());
        } catch (ParseException e) {
            ();
        }
//第二种
try {
    // 字符串转Date
    Date strParseDate = ("2020-01-01 00:00:00");
    // 字符串转Calender 先转为Date再转Calender
    Calendar strParseCalendar = ();
    (strParseDate);
} catch (ParseException e) {
     ();
}

日期转字符串

import ;
import ;
 
//日期转字符串
public class Main{
    public static void main(String[] args){
        Date date = new Date();
        String strDateFormat = "yyyy-MM-dd HH:mm:ss";
        SimpleDateFormat sdf = new SimpleDateFormat(strDateFormat);
        ((date));
    }
}

字符串转Date

try {
    // 字符串转Date
    Date strParseDate = ("2020-01-01 00:00:00");
    // 字符串转Calender 先转为Date再转Calender
    Calendar strParseCalendar = ();
    (strParseDate);
} catch (ParseException e) {
     ();
}

日期转时间戳

// date转时间戳
Date date = new Date();
long dateTimeStamp = ();
// Calender转时间戳
Calendar calendar = ();
long calTimeStamp = ().getTime();
// String转时间戳
Timestamp ts = ("2020-01-01 00:00:00");
long strTimeStamp = ();
// LocalDateTime转时间戳
// 获取秒数
Long second = ().toEpochSecond(("+8"));
// 获取毫秒数
Long milliSecond = ().toInstant(("+8")).toEpochMilli();

时间戳转日期

long timestamp = 1326499860000L;
// 时间戳转Date
Date timeStampDate = new Date(timestamp);
// 时间戳转Calender
Calendar timeStampCalendar = ();
(timestamp);
// 时间戳转String
String timeStampStr = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(timestamp);
// 时间戳转LocalDateTime
LocalDateTime timeStampLocalDateTime =  (timestamp,0, (8));