Question

DateConversion程序将用户输入的日期格式转换为另一种格式。该程序运行良好，输入格式为mm / dd / yyyy，但如果用户输入1999年1月28日而不是01/28/1999，程序仍应显示1999年1月28日。可以进行哪些修改。任何帮助都会受到欢迎！代码：

import java.util.Scanner; //Importing java Scanner
public class DateConversion { 
    public static void main (String[] args){ // Main method

        String enteredDate; // Declaring a string
        char answer = 'Y'; // Assigning a character value to variable answer
        String response; // Declaring a string for user's response
        Scanner keyboard = new Scanner (System.in); // Scanner object

        do { // A do-while loop used to check and convert the date format if user enters y otherwise terminate
        System.out.println("Please enter a date in mm/dd/yyyy format: "); // Asking for user input
        enteredDate = keyboard.nextLine(); // Taking the user's input

        // If, else if loops are used to check the months entered, convert and display them in another format
        // This is done by checking characters at various positions

        if (enteredDate.charAt(0)== '0' && enteredDate.charAt(1) == '1'){ 
            System.out.println("Display date in other format: ");
            System.out.println("January " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '0' && enteredDate.charAt(1) == '2' ){
            System.out.println("Display date in other format: ");
            System.out.println("February " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '0' && enteredDate.charAt(1) == '3' ){
            System.out.println("Display date in other format: ");
            System.out.println("March " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '0' && enteredDate.charAt(1) == '4' ){
            System.out.println("Display date in other format: ");
            System.out.println("April " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '0' && enteredDate.charAt(1) == '5' ){
            System.out.println("Display date in other format: ");
            System.out.println("May " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '0' && enteredDate.charAt(1) == '6' ){
            System.out.println("Display date in other format: ");
            System.out.println("June " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '0' && enteredDate.charAt(1) == '7' ){
            System.out.println("Display date in other format: ");
            System.out.println("July " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '0' && enteredDate.charAt(1) == '8' ){
            System.out.println("Display date in other format: ");
            System.out.println("August " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '0' && enteredDate.charAt(1) == '9' ){
            System.out.println("Display date in other format: ");
            System.out.println("September " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '1' && enteredDate.charAt(1) == '0' ){
            System.out.println("Display date in other format: ");
            System.out.println("October " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '1' && enteredDate.charAt(1) == '1' ){
            System.out.println("Display date in other format: ");
            System.out.println("November " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        else if (enteredDate.charAt(0)== '1' && enteredDate.charAt(1) == '2' ){
            System.out.println("Display date in other format: ");
            System.out.println("December " +enteredDate.charAt(3)+""+enteredDate.charAt(4)+", "+enteredDate.charAt(6)+""+enteredDate.charAt(7)+""+enteredDate.charAt(8)+""+enteredDate.charAt(9));
        }
        System.out.println(); // Used for line break
        System.out.printf("Do you want to continue (y/n): "); // Asking the user if they want to continue

        response = keyboard.nextLine(); // User's response
        answer = response.charAt(0); // Getting the character at 0th position
        } while (Character.toUpperCase (answer) == 'Y'); // Checking if the character obtained is y
    }
}

Answer 1

如果String.split在范围内，请使用它将用户输入的日期字符串拆分为月份，日期和年份。例如，如果用户打算在1月份，月份可能会String或1为01。

    String[] splitDate = enteredDate.split("/");

这将为您提供三个字符串的数组。您可能需要检查数组的长度是否为3，如果没有则发出错误消息（如果它更短或更长）。因此，您可以将月份数字符串作为splitDate[0]等访问。如果您有疑问，请阅读数组。

如果不允许String.split，请使用String.substring将月份取消为{1}}或1作为1月份。这需要您知道斜杠的位置。使用01或indexOf查找。白天和同年也一样。

如果您知道charAt语句，请启用您刚刚获得的月份字符串。案例前可能有多个案例标签，例如：

switch

（另一种选择是switch (monthNumberString) { case "01": case "1": System.out.print("January"); break; case "02": case "2": System.out.print("February"); break; // Etc. for other months }用于保存从数字字符串到月份名称的映射，但我认为这也超出了界限。）

如果你不知道Map（或者不允许使用它），你仍然可以在if语句中使用month子字符串：

switch

轻微的建议：

最后使用if (monthNumberString.equals("01") || monthNumberString.equals("1"))部分（如果使用else语句，则使用default个案例）打印有关无法识别的月份的消息。
在需要之前不要声明变量。在您的程序中switch和enteredDate可以在response循环中声明，您首先使用它们，以便更容易在代码中找到解决方法。

格式化日期转换java

1 个答案: