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Check that the String does not contain certain characters in Java
Let’s say the following is our string with special characters.
String str = "test*$demo";
Check for the special characters.
Pattern pattern = Pattern.compile("[^A-Za-z0-9]");
Matcher match = pattern.matcher(str);
boolean val = match.find();Now, if the bool value “val” is true, that would mean the special characters are in the string.
if (val == true)
System.out.println("Special characters are in the string.");Example
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Demo {
public static void main(String []args) {
String str = "test*$demo";
System.out.println("String: "+str);
Pattern pattern = Pattern.compile("[^A-Za-z0-9]");
Matcher match = pattern.matcher(str);
boolean val = match.find();
if (val == true)
System.out.println("Special characters are in the string.");
else
System.out.println("Special characters are not in the string.");
}
}Output
String: test*$demo Special characters are in the string.
The following is another example with a different input.
Example
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Demo {
public static void main(String []args) {
String str = "testdemo";
System.out.println("String: "+str);
Pattern pattern = Pattern.compile("[^A-Za-z0-9]");
Matcher match = pattern.matcher(str);
boolean val = match.find();
if (val == true)
System.out.println("Special characters are in the string.");
else
System.out.println("Special characters are not in the string.");
}
}Output
String: testdemo Special characters are not in the string...
Updated on: 27-Jun-2020
3K+ Views
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