//格式化数据
SimpleDateFormat sdf =new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String format = sdf.format(new Date());
System.out.println(format);//String格式的数据转化成Date格式
String timeStr = "2019-07-09 03:34:56 ";
Date parse = sdf.parse(timeStr);
System.out.println(parse);