Java Pattern compile(String)方法及示例

Java中 Pattern 类的 compile(String) 方法是用来从作为参数传递给方法的正则表达式中创建一个模式。每当你需要将一个文本与正则表达式模式进行多次匹配时，请使用Pattern.compile()方法创建一个Pattern实例。
语法

public static Pattern compile(String regex)

参数： 该方法接受一个单参数 regex ，代表给定的正则表达式被编译成一个模式。
返回值： 该方法返回由作为参数传递给该方法的regex编译的模式。
异常： 该方法抛出以下异常。

PatternSyntaxException： 如果表达式的语法无效，则抛出该异常。

以下程序说明了compile(String)方法：
程序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.*";
 
        // creare 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);
    }
}

输出

actualString contains REGEX = true

程序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";
 
        // creare 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);
    }
}

输出