java怎么把一个string个日期类型 如“Fri Feb 01 00:00:00 GMT+08:00 2013”转换成“yyyy-mm-dd”

String dateString = "Fri Feb 01 00:00:00 GMT+08:00 2013";        SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy",Locale.US);        TimeZone tz = TimeZone.getTimeZone("GMT+8");        sdf.setTimeZone(tz);        String str = sdf.format(Calendar.getInstance().getTime());        System.out.println(str);        Date s;        try {            s = sdf.parse(dateString);            sdf = new SimpleDateFormat("yyyy-MM-dd");            System.out.println(sdf.format(s));        } catch (ParseException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }