用Java实现今天、昨天、前天的日期小例子。

下面是用Java实现今天、昨天、前天的日期小例子,大家可以试试，有什么问题我们互相讨论。
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
public class TestStr {
public static void main(String[] args) {
   getDates();
}
public static void getDates() {
   int currYear,currMonth,currDate;
   Calendar calendar=Calendar.getInstance();
   currYear=calendar.get(Calendar.YEAR);
     currMonth=calendar.get(Calendar.MONTH)+1;
   currDate=calendar.get(Calendar.DATE);
   System.out.println("今天："+currYear+"-"+currMonth+"-"+currDate);
   //判断昨天是不是上一年。
   if (currMonth==1&&currDate==1) {//是一月一号
    System.out.println("--------1111---------");
    System.out.println("昨天是："+(currYear-1)+"-"+12+"-"+31);
    System.out.println("前天是："+(currYear-1)+"-"+12+"-"+(31-1));
   }
   else if (currMonth==1&&currDate==2) {//是一月一号
    System.out.println("--------222---------");
    System.out.println("昨天是："+(currYear)+"-"+currMonth+"-"+(currDate-1));
    System.out.println("前天是："+(currYear-1)+"-"+12+"-"+31);
   }
   else if (currMonth>1&&currDate>2) {
    System.out.println("--------333---------");
    System.out.println("昨天是："+(currYear)+"-"+currMonth+"-"+(currDate-1));
    System.out.println("前天是："+(currYear-1)+"-"+currMonth+"-"+(currDate-2));
   }
   else if (currMonth>1&&currDate==2) {
    System.out.println("--------4444---------");
    System.out.println("昨天是："+(currYear)+"-"+currMonth+"-"+(currDate-1));
    System.out.println("前天是："+(currYear-1)+"-"+(currMonth-1)+"-"+(getLastDayOfUpMonth(currYea