The compile(String) method of the Pattern class in Java is used to create a pattern from the regular expression passed as parameter to method. Whenever you need to match a text against a regular expression pattern more than one time, create a Pattern instance using the Pattern.compile() method.
Syntax:
public static Pattern compile(String regex)
Parameters: This method accepts one single parameter regex which represents the given regular expression compiled into a pattern.
Return Value: This method returns the pattern compiled from the regex passed to the method as a parameter.
Exception: This method throws following exception:
- PatternSyntaxException: This exception is thrown if the expression’s syntax is invalid.
Below programs illustrate the compile(String) method:
Program 1:
// Java program to demonstrate // Pattern.compile() method import java.util.regex.*;
public class GFG {
public static void main(String[] args)
{
// create a REGEX String
String REGEX = ".*www.*" ;
// create the string
// in which you want to search
String actualString
= "www.geeksforgeeks.org" ;
// compile the regex to create pattern
// using compile() method
Pattern pattern = Pattern.compile(REGEX);
// get a matcher object from pattern
Matcher matcher = pattern.matcher(actualString);
// check whether Regex string is
// found in actualString or not
boolean matches = matcher.matches();
System.out.println( "actualString "
+ "contains REGEX = "
+ matches);
}
} |
actualString contains REGEX = true
Program 2:
// Java program to demonstrate // Pattern.compile method import java.util.regex.*;
public class GFG {
public static void main(String[] args)
{
// create a REGEX String
String REGEX = "brave" ;
// create the string
// in which you want to search
String actualString
= "Cat is cute" ;
// compile the regex to create pattern
// using compile() method
Pattern pattern = Pattern.compile(REGEX);
// check whether Regex string is
// found in actualString or not
boolean matches = pattern
.matcher(actualString)
.matches();
System.out.println( "actualString "
+ "contains REGEX = "
+ matches);
}
} |
actualString contains REGEX = false
Reference: https://docs.oracle.com/javase/10/docs/api/java/util/regex/Pattern.html#compile(java.lang.String)