/**
	 * 生成随机图片文件名，年月日时分秒格式
	 */
	 String getString() {
		Date date = new Date(System.currentTimeMillis());
		SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMddHHmmss");
		String string = simpleDateFormat.format(date);
		return string;
	}
 
 

方式一：
 
Calendar calendar = Calendar.getInstance();
System.out.println(calendar.get(Calendar.YEAR));
System.out.println(calendar.get(Calendar.MONTH)+1);
System.out.println(calendar.get(Calendar.DATE));
 
方式二：
 
String[] strNow = new SimpleDateFormat("yyyy-MM-dd").format(new Date()).toString().split("-");
Integer year = Integer.parseInt(strNow[0]);
Integer month = Integer.parseInt(strNow[1]);
Integer day = Integer.parseInt(strNow[2]);
 
js方式：
 
var now = new Date();
year = now.getFullYear();
month = now.getMonth()+1;
var day = now.getDate();
 
 

public static Map<String, Object> getDateMap(long cha) {
         Calendar calendar = Calendar.getInstance();
         int year = calendar.get(Calendar.YEAR);
         int month = calendar.get(Calendar.MONTH) + 1;// 记得加1
         int day = calendar.get(Calendar.DATE);
         String sfm = " 00:00:00.00";
         String begins = year + "-" + month + "-" + day + sfm;
 
        // String转换为java.sql.Timestamp，String格式：yyyy-mm-dd hh:mm:ss[.f...]
         // ，方括号表示可选
         Timestamp beginst = Timestamp.valueOf(begins);
         long bl = beginst.getTime();
         Timestamp endst = new Timestamp(bl + cha);
         Map<String, Object> map = new HashMap<>();
         if (cha >= 0) {
             map.put("beginst", beginst);
             map.put("endst", endst);
         } else {
             map.put("beginst", endst);
             map.put("endst", beginst);
         }
         return map;
     }

两种方式，选择其一即可
 
1、SimpleDateFormat
 
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");  
String dateNow = sdf.format(new Date());  
System.out.println("当前时间为："+dateNow);

//具体的年、月、日可利用substring截取
//dateNow.substring(开始下标，结束下标),下标原则：从0开始，包前不包后
System.out.println(dateNow.substring(0,4)+"年"+dateNow.substring(5,7)+"月"+dateNow.substring(8,10)+"日");
        
 
 
2、Calendar
 
Calendar now = Calendar.getInstance();  
String nian=now.get(Calendar.YEAR)+"";
int mon=(now.get(Calendar.MONTH) + 1);
int dat=now.get(Calendar.DAY_OF_MONTH);
String yue=mon+""; //月份
String ri=dat+"";  //日期
if(mon<10){ //小于两位数前面补0
    yue="0"+mon;
}
if(dat<10){//小于两位数前面补0
    ri="0"+dat;
}

System.out.println(nian+"年"+yue+"月"+ri+"日");