java 时间字符串和时间戳（长整形long）之间的互转

import java.util.Date;import java.text.SimpleDateFormat;class Test {    public static void main(String[] args) {        Date date1 = new Date();        long l = date1.getTime();        System.out.println(l);        long date2 = System.currentTimeMillis();        System.out.println(date2);        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        String date3 = sdf.format(new Date().getTime());        System.out.println(date3);    }}