arraylist和vector，date和calendar

arraylist和vector简单的来说就是vector自带多线程同步，安全性更高，因为在不同步的时候就会抛出一个必须捕获的Exception，相应的效率会低。而arraylist的安全性没有vector高，效率更高。

 

date在新版本可能不再被支持，所以使用calendar会更好。calendar获取时间的代码

 

 

private static Calendar calendar;/** * 获得年月日 * @return string */public static String getDate(){calendar = Calendar.getInstance();StringBuffer dateBuffer = new StringBuffer();dateBuffer.append(calendar.get(Calendar.YEAR)+"年");dateBuffer.append(calendar.get(Calendar.MONTH)+"月");dateBuffer.append(calendar.get(Calendar.DAY_OF_MONTH)+"日");return dateBuffer.toString();}/** * 获得星期 * @return string */public static String getWeek(){calendar = Calendar.getInstance();StringBuffer weekBuffer = new StringBuffer();weekBuffer.append("星期");switch (calendar.get(Calendar.DAY_OF_WEEK)) {case Calendar.SUNDAY:weekBuffer.append("日");break;case Calendar.MONDAY:weekBuffer.append("一");break;case Calendar.TUESDAY:weekBuffer.append("二");break;case Calendar.WEDNESDAY:weekBuffer.append("三");break;case Calendar.THURSDAY:weekBuffer.append("四");break;case Calendar.FRIDAY:weekBuffer.append("五");break;case Calendar.SATURDAY:weekBuffer.append("六");break;default:break;}return weekBuffer.toString();}/** * 获得具体时间 * @return string */public static String getHour(){calendar = Calendar.getInstance();StringBuffer hourBuffer = new StringBuffer();switch (calendar.get(Calendar.AM_PM)) {case Calendar.AM:hourBuffer.append("上午");break;case Calendar.PM:hourBuffer.append("下午");break;default:break;}hourBuffer.append(calendar.get(Calendar.HOUR)+"时");hourBuffer.append(calendar.get(Calendar.MINUTE)+"分");hourBuffer.append(calendar.get(Calendar.SECOND)+"秒");return hourBuffer.toString();}