joda-time操作日期

        //当前日期
    	DateTime begin = DateTime.now();
    	//在begin的基础上增加4天
    	DateTime end = begin.plusDays(4);
    	
    	//计算区间天数  
    	Period pe = new Period(begin, end, PeriodType.days()); 
    	int days = pe.getDays();  
    	System.out.println(days);
    	
    	//格式化yyyyMMdd字符串
    	DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyyMMdd");  
    	DateTime dt = DateTime.parse("20140103", formatter);
    	
    	//打印为yyyy-MM-dd
    	System.out.println(dt.toString("yyyy-MM-dd"));
    	
    	//格式化yyyy-mm-dd字符串
    	DateTime dt0 = DateTime.parse("2014-01-03", DateTimeFormat.forPattern("yyyy-MM-dd"));
    	//打印为yyyymmdd
    	System.out.println(dt0.toString("yyyyMMdd"));
    	//转换为jdk的Date
    	java.util.Date dd = dt.toDate();