java 时间戳与date转换

long sjc=1442633777;              
SimpleDateFormat t = new SimpleDateFormat("yyyyMMddHHmmss");
String date = t.format(new Date(sjc*1000));
System.out.println(date);

SimpleDateFormat simpleDateFormat =new SimpleDateFormat("yyyyMMddHHmmss");
Date date=simpleDateFormat .parse("20150919102427");
long timeStemp =  date.getTime();
System.out.println(timeStemp );