Regex all special symbols java

Regex pattern including all special characters

To create a regular expression that includes all special characters, you can use the following pattern:

This regular expression will match any single special character in the list.

For example, you can use this regular expression to test if a string contains any special characters:

import java.util.regex.Matcher; import java.util.regex.Pattern; String input = "Hello World!"; Pattern pattern = Pattern.compile("[!@#%^&*()_+-=[]<>|;':\",./<>?~`]"); Matcher matcher = pattern.matcher(input); if (matcher.find()) < System.out.println("Input contains special characters."); > else < System.out.println("Input does not contain special characters."); >

This will output «Input does not contain special characters.»

Note that the regular expression includes several characters that must be escaped with a backslash ( \ ) because they have special meaning in a regular expression. These characters are [ , ] , ^ , — , \ , and ] .

Also, be aware that this regular expression will not match all possible special characters. It only includes the special characters that are commonly used in the ASCII character set. If you need to match all possible special characters, you can use the \p Unicode character property, which will match any Unicode punctuation character.

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Regex Special Characters in Java

1. Special Characters in Java Regular Expressions
2. Example of Using Regex Special Characters in Java

Regex (Regular Expression) is a useful tool for manipulating, searching, and processing text strings. It simplifies and reduces the number of lines in a program.

We’ll look at how special characters are utilized in regex.

Special Characters in Java Regular Expressions

Regex is a type of textual syntax representing patterns for text matching. Regular expressions make use of special characters such as . , + , * , ? , ^ , $ , ( , ) , [ , ] , < , >, | , \ .

Example of Using Regex Special Characters in Java

In this example, we used the Pattern and Matcher classes from the java.util.regex package. The Pattern class represents a regular expression.

When we create an instance of the Pattern class, we pass the regular expression as a string.

1. At least one digit 5 must be included in the password.
2. At least one lowercase character [a-z] is required in the password.
3. At least one uppercase character [A-Z] is required in the password.
4. At least one special character, such as ! @ # & () , must be included in the password.
5. A password must be at least 8 characters long and no more than 24 characters long.

The compile() method creates a pattern from the specified regular expression. We’ll use this pattern to make a Matcher object later.

This pattern can be matched with any character sequence against the regular expression using the Matcher object. The matcher method creates a matcher that matches the given input against the pattern.

We match two strings to the pattern and print the output (a Boolean returned by the matches() method).

import java.util.regex.Matcher; import java.util.regex.Pattern;  public class RegexTest   public static void main(String [] args)   String regex_pattern =  "^(?=.*5)(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#&()–[<>]:;',?/*~$^+=<>]).$";   Pattern pattern = Pattern.compile(regex_pattern);   String inputPassword1 = "Password1@@1990";  String inputPassword2 = "Pass190";   Matcher matcher1 = pattern.matcher(inputPassword1);  Matcher matcher2 = pattern.matcher(inputPassword2);   System.out.println("Password 1 matches pattern : "+matcher1.matches());  System.out.println("Password 2 matches pattern : "+matcher2.matches());   > > 

Password 1 matches pattern : true Password 2 matches pattern : false 

Rupam Saini is an android developer, who also works sometimes as a web developer., He likes to read books and write about various things.

Related Article — Java Regex

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How To Check String Contains Special Characters In Java?

According to Computerhope, a Special character is a character other than an alphabetic or numeric character. Examples of special characters are Punctuation marks and other symbols.

How to check string contains special characters in Java?

We can check whether the given string contains any special characters or not by using the below approaches:

Note: You can also refer to ASCII Table to get complete knowledge about ASCII values.

Let’s see all approaches with programs to check special characters in Strings.

Approach-1: How to check String contains special characters in java using ASCII value?

In this approach, We will use ASCII values to check whether characters of a String contain any special character or not.

As we have already given all ranges of ASCII values of special characters in the above table, we have to check for each range of ASCII values in the Java program.

Let’s see the program here.

Java program using ASCII value:

  <  < String str; Scanner sc = System.out.print(); str = sc.nextLine();  = = = = ); ); > >  Enter any   Explanation of ASCII value program: 

In the above program first, we will accept any String from the user(Line no 15 & 16). Then we have used for loop for(int i = 0; i < str.length(); i++) to iterate given String.

We have declared the asciiVal variable to store the ASCII value of each character before checking for a special character and we will use this asciiVal to check-in if( ) condition.

In the if( ) condition, we have taken multiple conditions to check for ASCII values. If String will contain any special characters, then we will change the value of the check to true. otherwise check will remain false. We have declared a boolean variable check (boolean check = false;) to use for true or false. So that by using this check variable we can display whether the given String contains any special character or not.

Finally, we have displayed the result using the print( ) method.

Approach-2: How to check String contains special characters in java using regex?

In this approach, we will use regex with java.util.regex.Matcher and java.util.regex.Pattern classes to check special characters in a String.

Let’s see the program here.

Java program using regex:

  <  < String str; Pattern checkPattern; Matcher match; System.out.print(); str = sc.nextLine(); checkPattern = Pattern.compile( match = checkPattern.matcher(str); check = match.find();  ); ); > >  Enter any   Explanation of regex program: 

In the above program, we have used the regex pattern [^a-zA-Z0-9] to check for all special characters.

First, we have compiled the given regex using compile( ) method of java.util.regex.Pattern class and then we have matched this pattern with the given String using matcher( ) method of java.util.regex.Matcher class.

Finally, we have checked that whether the given pattern of regex was found in String or not by using the find( ) function which returns type is a boolean. So find( ) the function will return either true or false and by using this check, we have displayed the result to the user.

Approach-3: How to check String contains special characters in java using all special characters?

In this approach, we will all special characters directly to check those special characters are present in a String or not.

Let’s check the program now.

Java program using special characters:

package cf.java.string;  < public  System.out.print(); str = sc.nextLine();  ); ); > >  Enter any   Explanation of special characters program: 

In the above program first, we have declared all special characters in a String as String specialChars = “!@#$%&*()’+,-./:;?[]^_`<|>”;specialChars.

Then by using for loop we have iterated the given String from index 0 to the last index. Inside for loop, we have declared a String strChar to store each character as String and then we have checked whether this String is present in specialChars String or not. If it is available then we will change the value of the check to true otherwise, it remains false.

Finally, by using the check variable we have displayed the result to the user.

Other readers also ask for:

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FAQs

What is a Special Character?

A special character is a character other than an alphabetic or numeric character. Examples of special characters are Punctuation marks and other symbols.

How to check string contains special characters in Java?

We can check whether the given string contains any special characters or not by using the below approaches:
Check special characters in java using ASCII value.
Check special characters in java using regex.
Check special characters in Java using all special characters.

What are the Special Characters?

Special Characters include !@#$%&*()’+,-./:;?[]^_` .

Which regex we can use to find Special Characters?

Regex: [^a-zA-Z0-9]

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