//生日字符串和整型
String birthDateString = "1999-09-09";
int year = 1999;
int month = 9;
int day = 9;
//将字符串转换为Date
DateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
//dateFormat = DateFormat.getInstance();
Date birthDate = dateFormat.parse(birthDateString);
System.out.println(birthDate);
//构建Date,已不推荐使用。年份从1900年开始,月份从0开始
birthDate = new Date(year - 1900, month - 1, day);
System.out.println(birthDate);
//Calendar类,月份从0开始
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.YEAR, year);
calendar.set(Calendar.MONTH, month- 1);
calendar.set(Calendar.DAY_OF_MONTH, day);
calendar.set(Calendar.HOUR_OF_DAY, 0); //设置时分秒
calendar.set(Calendar.MINUTE, 0);//设置时分秒
calendar.set(Calendar.SECOND, 0);//设置时分秒
calendar.set(Calendar.MILLISECOND, 0);//毫秒。。。
System.out.println(calendar.getTime());
表达不清晰,如用Data类输入一个人的生日?