正则表达式帮助替换子字符串

Question

I have a String:

StartTime-2014-01-14 12:05:00-StartTime

The requirement is to replace the timestamp with current timestamp.

I tried the below code which is not giving me the expected output:

String st = "StartTime-2014-01-14 12:05:00-StartTime"; 
String replace = "StartTime-2014-01-14 13:05:00-StartTime"; 
Pattern COMPILED_PATTERN = Pattern.compile(st, Pattern.CASE_INSENSITIVE); 
Matcher matcher = COMPILED_PATTERN.matcher(DvbseContent); 
String f = matcher.replaceAll(replace);

Expected Output is:

StartTime-<Current_Time_stamp>-StartTime

Answer 1

You could match it like this:

(StartTime-).*?(-StartTime)

and replace it with this (or similar):

"$1" + current_time_stamp + "$2"

---

Example Java Code:

import java.util.*;
import java.util.Date;
import java.lang.*;
import java.io.*;
import java.util.regex.*;

class Ideone
{
    public static void main (String[] args) throws java.lang.Exception
    {
        java.util.Date timestamp = new java.util.Date();
        String search = "StartTime-2014-01-14 12:05:00-StartTime";
        String regex = "(StartTime-).*?(-StartTime)";
        String replacement = "$1"+ timestamp + "$2";
        String result = search.replaceAll(regex, replacement);

        System.out.println(result);
    };
};

Output:

StartTime-Fri Feb 14 08:53:57 GMT 2014-StartTime

Answer 2

Or instead of Regex, you can just use indexOf and lastIndexOf:

String f = "StartTime-2014-01-14 12:05:00-StartTime";
String timestamp = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss")
                  .format(new java.util.Date());
String newString = f.substring(0, f.indexOf("-") + 1) 
                + timestamp 
                + f.substring(f.lastIndexOf("-"));

Output: StartTime-2014-02-10 12:52:47-StartTime