package com.ob;  
      
    import java.text.ParseException;  
    import java.text.SimpleDateFormat;  
    import java.util.Calendar;  
    import java.util.Date;  
      
    public class DateTest {  
      
        public static void main(String[] args) throws ParseException {  
            Calendar now = Calendar.getInstance();  
            System.out.println("年: " + now.get(Calendar.YEAR));  
            System.out.println("月: " + (now.get(Calendar.MONTH) + 1) + "");  
            System.out.println("日: " + now.get(Calendar.DAY_OF_MONTH));  
            System.out.println("时: " + now.get(Calendar.HOUR_OF_DAY));  
            System.out.println("分: " + now.get(Calendar.MINUTE));  
            System.out.println("秒: " + now.get(Calendar.SECOND));  
            System.out.println("当前时间毫秒数：" + now.getTimeInMillis());  
            System.out.println(now.getTime());  
      
            Date d = new Date();  
            System.out.println(d);  
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");  
            String dateNowStr = sdf.format(d);  
            System.out.println("格式化后的日期：" + dateNowStr);  
              
            String str = "2012-1-13 17:26:33";  //要跟上面sdf定义的格式一样  
            Date today = sdf.parse(str);  
            System.out.println("字符串转成日期：" + today);  
        }  
    }

输出结果：

年: 2012
月: 1
日: 13
时: 17
分: 28
秒: 19
当前时间毫秒数：1326446899902
Fri Jan 13 17:28:19 CST 2012
Fri Jan 13 17:28:19 CST 2012
格式化后的日期：2012-01-13 17:28:19
字符串转成日期：Fri Jan 13 17:26:33 CST 2012