关于Date/Calendar/String的三角恋

String Calendar Date之间的转换

1.Calendar 转化 String

Calendar calendar = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
String dateStr = sdf.format(calendar.getTime()); 
System.out.println(dateStr);

2.String 转化Calendar

String str="2012-5-27";
SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");
Date date =sdf.parse(str);
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);

3.Date 转化String

Date date = new Date();
SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");
String dateStr=sdf.format(date);
System.out.println(dateStr);

4.String 转化Date

String str="2012-5-27";
SimpleDateFormat sdf= new SimpleDateFormat("yyyy-MM-dd");
Date date= sdf.parse(str);
System.out.println(date);

5.Date 转化Calendar

Date date = new Date();
 Calendar calendar = new GregorianCalendar();
 calendar.setTime(date);
 System.out.println(calendar);

6.Calendar转化Date

Calendar calendar = new GregorianCalendar();
Date date =calendar.getTime();
System.out.println(date);