java 获取当前年月日，uuid获取

java中获取当前年月日使用Calendar类

//获取Calendar类

Calendar calendar = Calendar.getInstance();

//获取年

calendar.get(Calendar.YEAR);

//获取月
注：获取的月比真实月少1

calendar.get(Calendar.MONTH)+1;

获取UUID字符串方法:uuid中有-，所以可以用replace替换掉

UUID uuid = UUID.randomUUID();

String uuidString = uuid.toString().replace("-","");