In this example we are going to talk about matches String Class method. You can use this method to test a String against a regular expression. Testing a String against a regular expression is a very common operation for interactive applications, as it is heavily used to perform validity checks on user input. It can also be used for several other causes on a bigger scale, like filtering, pruning on large text data, searching text documents etc.
So as you might imagine, Java offers matches as a very simple API method to test Strings against regular expressions.
Let’s see some examples:
- Check if a sentence has only letters : [a-zA-Z *]+$
StringMacthesExample.java:
package com.javacodegeeks.core.string;
public class StringMacthesExample {
public static void main(String[] args) {
String s1 = "Java Code Geeks are awesome";
System.out.println(s1.matches("[a-zA-Z *]+$"));
}
}Output:
true- Check if a sentence has only alphanumerics : [a-zA-Z0-9 *]+$
StringMacthesExample.java:
package com.javacodegeeks.core.string;
public class StringMacthesExample {
public static void main(String[] args) {
String s1 = "Java 1 Code 2 Geeks 3 are awesome 15675";
System.out.println(s1.matches("[a-zA-Z0-9 *]+$"));
}
}Output:
true- Check if a string is an alphanumeric word: \w*$
StringMacthesExample.java:
package com.javacodegeeks.core.string;
public class StringMacthesExample {
public static void main(String[] args) {
String s1 = "Java8Rocks";
System.out.println(s1.matches("\\w*$"));
}
}Output:
true- Check if a string is a valid email address:^[_A-Za-z0-9-\+]+(\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\.[A-Za-z0-9]+)*(\.[A-Za-z]{2,})$
StringMacthesExample.java:
package com.javacodegeeks.core.string;
public class StringMacthesExample {
public static void main(String[] args) {
System.out.println("james.harlem@javacodegeeks.com"
.matches("^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"
+ "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*"
+ "(\\.[A-Za-z]{2,})$"));
}
}Output:
trueSo there you go. To learn more about Regular expression syntax you can checkout this site.
Download the Source Code
This was a Java String matches Example. You can download the source code of this example here : StringMatchesExample.zip
