Java 中的 Matcher group()方法,带示例

原文:https://www . geesforgeks . org/matcher-group-method-in-Java-with-examples/

使用匹配器类组()方法获取与前一个匹配结果匹配的输入子序列。

语法:

public String group()

参数:该方法不取任何参数。

返回值:该方法返回字符串,该字符串是与前一个匹配匹配的输入子序列。

异常:如果还没有尝试匹配,或者如果之前的匹配操作失败,此方法将抛出illegalstatexception

下面的例子说明了 Matcher.group()方法:

例 1:

// Java code to illustrate end() method

import java.util.regex.*;

public class GFG {
    public static void main(String[] args)
    {

        // Get the regex to be checked
        String regex = "(G*s)";

        // Create a pattern from regex
        Pattern pattern
            = Pattern.compile(regex);

        // Get the String to be matched
        String stringToBeMatched
            = "GeeksForGeeks";

        // Create a matcher for the input String
        Matcher matcher
            = pattern
                  .matcher(stringToBeMatched);

        // Get the current matcher state
        MatchResult result
            = matcher.toMatchResult();
        System.out.println("Current Matcher: "
                           + result);

        while (matcher.find()) {
            // Get the group matched using group() method
            System.out.println(matcher.group());
        }
    }
}

Output:

current Matcher:Java . util . regex . Matcher[pattern =(G * s)region = 0,13 lastmatch=] s s

例 2:

// Java code to illustrate end() method

import java.util.regex.*;

public class GFG {
    public static void main(String[] args)
    {

        // Get the regex to be checked
        String regex = "(G*G)";

        // Create a pattern from regex
        Pattern pattern
            = Pattern.compile(regex);

        // Get the String to be matched
        String stringToBeMatched
            = "GFG FGF GFG";

        // Create a matcher for the input String
        Matcher matcher
            = pattern
                  .matcher(stringToBeMatched);

        // Get the current matcher state
        MatchResult result
            = matcher.toMatchResult();
        System.out.println("Current Matcher: "
                           + result);

        while (matcher.find()) {
            // Get the group matched using group() method
            System.out.println(matcher.group());
        }
    }
}

Output:

当前匹配器:Java . util . regex . Matcher[pattern =(G * G)region = 0,11 last match =] G G G G G

参考: 甲骨文文档