有谁知道如何提取我的日期字符串并更改格式？

Question

I have a valid date in my String like this:

String strDate = "Available on 03292013";

I want to extract the date from the strDate String & change it to Available on 03/05/2015

Does anyone know how can I achieve this?

Answer 1

You can achieve this by doing the following steps:

• First, use the regex " [^0-9] " to extract the date from your String.
• Next, use the SimpleDateFormat to change the format of the extracted date from 'MMddyyyy' to 'MM/dd/yyyy'
• Finally, you have to append the formatted date String value to the String “Available on”.

Please find below code for better clarity on the implementation.

package com.stackoverflow.works;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @author sarath_sivan
 */

public class DateFormatHelper {

    private static final String DD_MM_YYYY = "MMddyyyy";
    private static final String DD_SLASH_MM_SLASH_YYYY = "MM/dd/yyyy";


    public static void main(String[] args) {
        DateFormatHelper  dateFormatHelper = new DateFormatHelper();
        dateFormatHelper.run();
    }

    public void run() {
        String strDate = "Available on 03292013";
        System.out.println("Input Date: " + strDate);
        strDate = DateFormatHelper.getDate(strDate); 
        strDate = "Available on " + DateFormatHelper.formatDate(strDate);
        System.out.println("Formatted Date: " + strDate);
    }

    public static String formatDate(String strDate) {
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat(DD_MM_YYYY);
        Date date;
        try {   
            date = simpleDateFormat.parse(strDate);
            simpleDateFormat = new SimpleDateFormat(DD_SLASH_MM_SLASH_YYYY);
            strDate = simpleDateFormat.format(date);
         } catch (ParseException parseException) {
             parseException.printStackTrace();
         }

        return strDate;
    }

    public static String getDate(String strDate) {
        return strDate.replaceAll("[^0-9]", "");
    }

}

Output:

Input Date: Available on 03292013
Formatted Date: Available on 03/29/2013

Hope this helps...

Answer 2

Try this simple and elegant approach.

DateFormat dateParser = new SimpleDateFormat("'Available on 'MMddyyyy");
DateFormat dateFormatter = new SimpleDateFormat("'Available on 'dd/MM/yyyy");
String strDate = "Available on 03292013";
Date date = dateParser.parse(strDate);
System.out.println(dateFormatter.format(date));

Answer 3

This should do what you want. Note that I'm just manipulating the String without any regards for what it actually contains (a date in this case).

String strDate = "Available on 03292013";
String newStr = strDate.substring(0, 15) + "/"
        + strDate.substring(15, 17) + "/" + strDate.substring(17);
System.out.println(newStr);

Result:

Available on 03/29/2013