java 和js 时间 格式化(yyyy-MM-dd HH:mm:ss) 以及获取当前时间

1、js

var myDate = new Date();
myDate.getYear(); //获取当前年份(2位)
myDate.getFullYear(); //获取完整的年份(4位,1970-????)
myDate.getMonth(); //获取当前月份(0-11,0代表1月)
myDate.getDate(); //获取当前日(1-31)
myDate.getDay(); //获取当前星期X(0-6,0代表星期天)
myDate.getTime(); //获取当前时间(从1970.1.1开始的毫秒数)
myDate.getHours(); //获取当前小时数(0-23)
myDate.getMinutes(); //获取当前分钟数(0-59)
myDate.getSeconds(); //获取当前秒数(0-59)
myDate.getMilliseconds(); //获取当前毫秒数(0-999)
myDate.toLocaleDateString(); //获取当前日期
var mytime=myDate.toLocaleTimeString(); //获取当前时间
myDate.toLocaleString( ); //获取日期与时间

getTimeNow() {
      var d = new Date()

    return d.getFullYear() + '-' + ((d.getMonth() < 9 ? '0' + (d.getMonth() + 1) : (d.getMonth() + 1))) +
          '-' + (d.getDate() < 10 ? '0' + d.getDate() : d.getDate()) + ' ' + (d.getHours() < 10 ? '0' + d.getHours() : d.getHours()) +
          ':' + (d.getMinutes() < 10 ? '0' + d.getMinutes() : d.getMinutes()) + ':' + (d.getSeconds() < 10 ? '0' + d.getSeconds() : d.getSeconds())

},

    S4() {
      return (((1 + Math.random()) * 0x10000) | 0).toString(16).substring(1)
    },
    get_uuid() {
      return (this.S4() + this.S4() + '-' + this.S4() + '-' + this.S4() + '-' + this.S4() + '-' + this.S4() + this.S4() + this.S4())
    }

public class DateDemo {
    public static void main(String[] args) {
        Calendar calendar = Calendar.getInstance();
        System.out.println("系统时间："+calendar);
        System.out.println("年份："+calendar.get(Calendar.YEAR));
        System.out.println("月份："+calendar.get(Calendar.MONTH));
        System.out.println("日份："+calendar.get(Calendar.DATE));
        System.out.println("小时："+calendar.get(Calendar.HOUR));
        System.out.println("分钟："+calendar.get(Calendar.MINUTE));
        System.out.println("秒钟："+calendar.get(Calendar.SECOND));
        System.out.println("星期："+calendar.get(Calendar.DAY_OF_WEEK_IN_MONTH));
        System.out.println("当前时间："+calendar.getTime());
        System.out.println("当前时间："+ new Date());
        //new Date(System.currentTimeMillis())
        System.out.println("当前时间数字形式："+ System.currentTimeMillis());
        //LONG SHORT FULL MEDUIM
        DateFormat dateFormat = DateFormat.getDateInstance(DateFormat.LONG, Locale.CHINA);
        DateFormat timeFormat = DateFormat.getTimeInstance(DateFormat.LONG, Locale.CHINA);
        String date1 = dateFormat.format(new Date());
        String time1 = timeFormat.format(new Date());
        System.out.println("DateFormat:" + date1+ time1);
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy年MM月dd日 E HH点mm分ss秒 SSS毫秒");
        String date2 = simpleDateFormat.format(new Date());
        System.out.println("simpleDateFormat："+date2);
        System.out.println("---" + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date()));
    }