How to Replace Multiple Characters in a String in Java?

In Java, replacing multiple characters string means replacing all existence of a set of characters with another set of characters. It is attainable through the String.replace() method. It replaces all presence of a substring or specified character with another substring or character. However, this method only allows replacing one character or substring at a time.

This article will illustrate the method to replace single or multiple characters in a string using Java.

How to Replace Multiple Characters in a String in Java?

For replacing several characters in a string in Java, users can use the “String.replaceAll()” method. It allows users to replace multiple characters or substrings using regular expressions.

Here are multiple examples that replace single or multiple characters in a string:

Example 1: Replace All Occurrences of a Single Character

In this example, users can utilize the “replace()” method to replace all occurrences of the character ‘o’ with the ‘*’ character in the “Hello, World!”:

class HelloWorld {

public static void main(String[] args) {

String originalString = "Hello, World!";

String newString = originalString.replace('o', '*');

System.out.println(newString);

}

}

Output

The output shows that all occurrences of the character ‘o’ have been replaced with the ‘*’ character.

Important: The replaceAll() method returns a new string and will not change the actual string.

Example 2: Replace all Occurrences of Multiple Characters

In this example, users can replace all happenings of vowels in the original string using a regular expression. Let us execute the below code:

class HelloWorld {

public static void main(String[] args) {

String originalString = "Hello Linuxhint World.";

String newString = originalString.replaceAll("[aeiou]", "*");

System.out.println(newString);

}

}

In the above code, the “[]” square brackets denote a character class, and any character such as “aeiou” within the brackets is matched. The * character is used to replace each matched character.

Output

The resulting string shows that multiple characters have been replaced successfully.

Example 3: Replace Multiple Characters with Different Characters

Users can utilize two replace() methods to perform replacements with different characters. Let us conduct an example:

class HelloWorld {

public static void main(String[] args) {

String originalString = "Johnson buys fox which is actually a dog.";

String newString = originalString.replace("fox", "cat").replace("dog", "cat");

System.out.println(newString);

}

}

In this example, replace all happenings of the word ‘fox‘ with the word ‘cat‘ and all presence of the ‘dog’ with ‘cat’.

Output

The resulting string replaces all multiple characters in a string.

Conclusion

To replace multiple characters in a string, use “replaceAll()” or “replace()” methods in Java. They allow users to replace single or multiple characters or substrings using regular expressions. It is important to consider the performance implications of each method, as some may be more efficient than others for large strings or frequent replacements.

How to Replace Multiple Characters in a String in Java?