java标准化日期格式与毫秒时间戳之间的转换

import java.text.ParseException;
import java.text.SimpleDateFormat;



public class dateFormatUtil {
    public static void main(String[] args) throws ParseException {
        long time = System.currentTimeMillis();
        System.out.println(time);
        System.out.println(timeToFormat(time));
        System.out.println(timeToSecond(timeToFormat(time)));
    }
	//13位毫秒时间戳  -->  yyyy-MM-dd HH:mm:ss
    public static String timeToFormat(long time) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式
        return sdf.format(time);
    }
    //yyyy-MM-dd HH:mm:ss  -->  13位毫秒时间戳
    public static long timeToSecond(String date) throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        return sdf.parse(date).getTime();
    }
}