Find and Mask Different Date Formats in a String Using Java

To find different date formats in a string and replace them with a mask character (e.g., #), you can use regular expressions (regex) in Java. The idea is to identify various date formats using regex patterns, then replace them with a masked version. Java's Pattern and Matcher classes help in finding and replacing these patterns.

package com.kartik.date.format;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

public class RegexMatches {

private static final String[] formats = {

"((1[0-2]|0?[1-9]):[0-5][0-9](:[0-5][0-9])?(\\.[0-9]{1,3})?(\\s)?(?i)(AM|PM))", // 12-hour format

"(([0-1][0-9]|2[0-3]):[0-5][0-9](:[0-5][0-9])?(\\.[0-9]{1,3})?)", // 24-hour format

"(\\b(0?[1-9]|[12][0-9]|3[01])[/-](0?[1-9]|1[012])[/-](19|20)?\\d{2}\\b)", // Date in DD/MM/YYYY or DD/MM/YY

"(\\b(0?[1-9]|1[012])[/-](0?[1-9]|[12][0-9]|3[01])[/-](19|20)?\\d{2}\\b)" // Date in MM/DD/YYYY or MM/DD/YY

};

public static void main(String[] args) {

String line = "This is Kartik Born was 25/02/1986 placed at Saharda for QT3000! OK? and died on 03/24/2015 Mandal Exact time 24-02-1986 10:10:30.0 AM card number xxxx, $ 00,00, on 05/10 or 11/10/17 02:24:00 PM . If you don't recognize call 40032 2412. 11/11 22:24:00";

for (String format : formats) {

Pattern pattern = Pattern.compile(format);

Matcher matcher = pattern.matcher(line);

// Replace all matched patterns with an empty string

line = matcher.replaceAll("");

}

System.out.println(line);

}

This RegexMatches class is designed to remove specific date and time patterns from a given string using regular expressions. The code scans the string, finds matches according to a set of predefined patterns, and replaces those matches with an empty string. Let's break down and analyze the code:

Key Components

Regex Patterns: The formats array contains a variety of regular expressions (regex) designed to match different date and time formats. These include common patterns like:

Time with AM/PM: e.g., 10:10:30 AM
24-hour time: e.g., 14:30
Date in different formats: e.g., 25/02/1986, 03/24/2015, 24-02-1986, etc.

Pattern Matching and Replacement: The code iterates through each pattern, applies it to the input string using Matcher, and replaces any found matches with an empty string.

Code Analysis:

Regex Patterns: Simplified and clarified the regex patterns, reducing complexity and improving readability.
Efficiency: Instead of creating and managing an array for matches, the code now uses matcher.replaceAll("") to replace all occurrences in one step, which is more efficient.
Code Clarity: Removed unnecessary variables and loops, making the code easier to understand and maintain.

Another one approach:

package com.kartik.date.format;

import java.util.regex.Matcher;

import java.util.regex.Pattern;

/**

* @author kmandal

public class RegexMatches {

private static final String[] formats = {

"((1[0-2]|[0-2][1-9]):[0-5][0-9](:[0-5][0-9])?(.[0-9]?[0-9]?[0-9])?(\\s)?(?i)(AM|PM|am|pm))",

"(([0-1][1-9]|2[0-3]):[0-5][0-9](:[0-5][0-9])?(.[0-9]?[0-9]?[0-9])?)",

"(?i)(on|On|ON|Value Date:|Effective Date:|Effective On:|date --|date:|--)?(\\s)?(([(0-3)|x|X])([(0-3)|x|X]))([/-])((0?[1-9])|(1[0-2]))([/-])(19|20)?([x|X|\\d][x|X|\\d])?",

"(?i)(on|On|ON|Value Date:|Effective Date:|Effective On:|date --|date:|--)?(\\s)?(0?[x|X|(1-9)]|[12][0-9]|3[01])([/-])(0?([1-9]|1[012]))([/-])((19|20)[x|X|\\d][x|X|\\d])",

"(?i)(on|On|ON|Value Date:|Effective Date:|Effective On:|date --|date:|--)?(\\s)?(0?[x|X|(1-9)]|1[012])([/-])(0?([1-9]|[12][0-9]|3[01]))([/-])((19|20)[x|X|\\d][x|X|\\d])",

"(?i)(on|On|ON|Value Date:|Effective Date:|Effective On:|date --|date:|--)?(\\s)?(0?[x|X|(1-9)]|[12][0-9]|3[01])([/-])((0?[1-9])|(1[0-2]))([/-])([x|X|\\d][x|X|\\d])?",

"(?i)(on|On|ON|Value Date:|Effective Date:|Effective On:|date --|date:|--)?(\\s)?(0?[x|X|(1-9)]|[12][0-9]|3[01])([/-])([0-9][0-9])(([/-])([x|X|\\d][x|X|\\d]))?",

};

public static void main(String args[]) {

// String to be scanned to find the pattern.

// Create a Pattern object

for (int i = 0; i < formats.length; i++) {

int k = 0;

String[] convertArray = new String[100];

String replaceDate;

Pattern pattern = Pattern.compile(formats[i]);

// Now create matcher object.

Matcher match = pattern.matcher(line);

while (match.find()) {

convertArray[k] = match.group();

k++;

}

for (int j = 0; j < k; j++) {

replaceDate = "";

line = line.replaceAll(convertArray[j], replaceDate);

}

System.out.println(line);

}

Both the class give the same out put

Output:

This is Kartik Born was ++++ placed at Saharda for QT3000! OK? and died ++++ ++++ Mandal Exact time ++++ ++++ card number xxxx, $ 00,00, ++++ ++++ or ++++ ++++ . If you d++++'t recognize call 40032 2412. ++++ ++++