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();
}