Java 日期判断
1 package Test8_19; 2 3 import java.util.Scanner; 4 5 public class CheckDate { 6 public static void main(String args[]) { 7 CheckDate cd = new CheckDate(); 8 Scanner reader = new Scanner(System.in); 9 while (true) { 10 System.out.println("Enter a date:"); 11 String date = reader.nextLine(); 12 if (cd.CheckDateFormat(date)) { 13 System.out.println("Yes"); 14 } else { 15 System.out.println("No"); 16 17 } 18 } 19 } 20 21 public boolean CheckDateFormat(String date) { 22 String regex = "[1-2]\\d{3}.[0-1][0-9].[0-3][0-9]"; 23 24 if (date.matches(regex)) { 25 // get year month day of String 26 String year = date.substring(0, 4); 27 String month; 28 String day = date.substring(8,10); 29 30 if (date.substring(5, 6).equals("0")) { 31 month = date.substring(6, 7); // 0-9 month 32 } else { 33 month = date.substring(5, 7); // 10-12 month 34 } 35 36 if (date.substring(8, 9).equals("0")) { 37 day = date.substring(9, 10); // 0-9 day 38 } else { 39 day = date.substring(8, 10); // 10-31 day 40 } 41 // get year month day of int 42 int y = Integer.parseInt(year); 43 int m = Integer.parseInt(month); 44 int d = Integer.parseInt(day); 45 System.out.println("y="+y+" m="+m+" d="+d); 46 47 //if ((m >= 1 && m <= 12) && (d >= 1 && d <= 31)) { 48 switch(m){ 49 case 2:if (isLeapYear(y)) { 50 if (d <= 29) { 51 return true; 52 } else { 53 return false; 54 } 55 } 56 else{ if (d <= 28) { 57 return true; 58 } else { 59 return false; 60 } 61 } 62 63 case 1: 64 case 3: 65 case 5: 66 case 7: 67 case 8: 68 case 10: 69 case 12:if (d <= 31) { 70 return true; 71 } else { 72 return false; 73 } 74 case 4: 75 case 6: 76 case 9: 77 case 11:if (d <= 30) { 78 return true; 79 } else { 80 return false; 81 } 82 default:return false; 83 84 } 85 } 86 else{ 87 return false; 88 } 89 } 90 91 92 93 public boolean isLeapYear(int year) { 94 if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) { 95 return true; 96 } else { 97 return false; 98 } 99 } 100 101 }
改进：加入对当前日判断
1 public boolean accountDateOfOpening(String date) { 2 String regex = "[1-2]\\d{3}.[0-1][0-9].[0-3][0-9]"; 3 String month1 = null; 4 String month; 5 if (date.matches(regex)) { 6 // get year month day of String 7 String year = date.substring(0, 4); 8 String day = date.substring(8,10); 9 10 if (date.substring(5, 6).equals("0")) { 11 month = date.substring(6, 7); // 0-9 month 12 month1= date.substring(5, 7); 13 } else { 14 month = date.substring(5, 7); // 10-12 month 15 } 16 17 String enterDate=year+month1+day; 18 Date nowdate=new Date(); 19 SimpleDateFormat dateFormat = new SimpleDateFormat("yyyyMMdd"); 20 String nowDateString=dateFormat.format(nowdate); 21 //System.out.println("enterdate: "+enterDate); 22 //System.out.println("nowDateString: "+nowDateString); 23 //System.out.println("compare: "+(enterDate.compareTo(nowDateString)>=0)); 24 if(enterDate.compareTo(nowDateString)>=1){ 25 System.out.println("Date cannot be more than today!"); 26 return false; 27 } 28 29 if (date.substring(8, 9).equals("0")) { 30 day = date.substring(9, 10); // 0-9 day 31 } else { 32 day = date.substring(8, 10); // 10-31 day 33 } 34 // get year month day of int 35 int y = Integer.parseInt(year); 36 int m = Integer.parseInt(month); 37 int d = Integer.parseInt(day); 38 if(d==0){ 39 return false; 40 } 41 switch(m){ 42 case 2:if (isLeapYear(y)) { 43 if (d <= 29) { 44 return true; 45 } else { 46 return false; 47 } 48 } 49 else{ if (d <= 28) { 50 return true; 51 } else { 52 return false; 53 } 54 } 55 // break; 56 case 1: 57 case 3: 58 case 5: 59 case 7: 60 case 8: 61 case 10: 62 case 12:if (d <= 31) { 63 return true; 64 } else { 65 return false; 66 } 67 case 4: 68 case 6: 69 case 9: 70 case 11:if (d <= 30) { 71 return true; 72 } else { 73 return false; 74 } 75 default:return false; 76 77 } 78 } 79 else{ 80 return false; 81 } 82 } 83 84 85 // year is Leap Year or not 86 public boolean isLeapYear(int year) { 87 if (year % 4 == 0 && year % 100 != 0 || year % 400 == 0) { 88 return true; 89 } else { 90 return false; 91 } 92 }
