java string 转date方法如何实现

String s = "2012-08-25";
SimpleDateFormat sdf1 = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy年M月d日");
try {
System.out.println(sdf2.format(sdf1.parse(s)));
} catch (ParseException e) {
// TODO Auto-generated catch block
//www.heatpress123.net
e.printStackTrace();
}

String str = "2012/08/25";
SimpleDateFormat sdf3 = new SimpleDateFormat("yyyy/MM/dd");
SimpleDateFormat sdf4 = new SimpleDateFormat("yyyy年MM月dd日");
try {
System.out.println(sdf4.format(sdf3.parse(str)));
} catch (ParseException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}