code: public static FastDateFormat getDateTimeInstance(final int dateStyle, final int timeStyle, final Locale locale) {
  		return cache.getDateTimeInstance(dateStyle, timeStyle, null, locale);
  	}
docs: 获得 {@link FastDateFormat} 实例<br>
  支持缓存
  
  @param dateStyle date style: FULL, LONG, MEDIUM, or SHORT
  @param timeStyle time style: FULL, LONG, MEDIUM, or SHORT
  @param locale {@link Locale} 日期地理位置
  @return 本地化 {@link FastDateFormat}