将字符串格式化为指定的日期格式

String publish_date = "20091231125530";
SimpleDateFormat sdf_in = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat sdf_out = new SimpleDateFormat("yyyyMMddHHmmss");
Date fieldDate = null;
try {
 fieldDate = sdf_out.parse(publish_date);
} catch (ParseException e) {
 e.printStackTrace();
}
publish_date = sdf_in.format(fieldDate);