java pattern详解_Java Pattern pattern()用法及代码示例

Java中Pattern类的pattern()方法用于获取正则表达式，将其编译以创建此模式。我们使用正则表达式创建模式，并且使用此方法来获取相同的源表达式。

用法:

public String pattern()

参数：此方法不接受任何内容作为参数。

返回值：此方法返回模式的源正则表​​达式。

以下示例程序旨在说明pattern()方法：

示例1:

// Java program to demonstrate

// Pattern.pattern() method

import java.util.regex.*;

public class GFG {

public static void main(String[] args)

{

// create a REGEX String

String REGEX = “(.*)(for)(.*)?”;

// create the string

// in which you want to search

String actualString

= “code of Machine”;

// create pattern

Pattern pattern1 = Pattern.compile(REGEX);

// find the regular expressio of pattern

String RegularExpression = pattern1.pattern();

System.out.println(“Pattern’s RegularExpression = “

+ RegularExpression);

}

}

输出：

Pattern’s RegularExpression = (.*)(for)(.*)?

示例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 = “(.*)(ee)(.*)?”;

// create the string

// in which you want to search

String actualString

= “geeks”;

// create pattern

Pattern pattern1 = Pattern.compile(REGEX);

// find the regular expressio of pattern

String RegularExpression = pattern1.pattern();

System.out.println(“Pattern’s RegularExpression = “

+ RegularExpression);

}

}

输出：

Pattern’s RegularExpression = (.*)(ee)(.*)?