Java Matcher usePattern(Pattern)用法及代码示例

Matcher类的usePattern()方法用于获取此匹配器要匹配的模式。

用法:

public Matcher usePattern(Pattern newPattern)

参数：此方法采用参数newPattern，它是要设置的新模式。

返回值：此方法返回具有新Pattern的Matcher。

异常：如果newPattern为null，则此方法引发IllegalArgumentException。

下面的示例说明Matcher.usePattern()方法：

示例1:

// Java code to illustrate usePattern() method 
  
import java.util.regex.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Get the regex to be checked 
        String regex = "Geeks"; 
  
        // 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 new Pattern 
        String newPattern = "GFG"; 
  
        // Get the Pattern using pattern method 
        System.out.println("Old Pattern: "
                           + matcher.pattern()); 
  
        // Set the newPattern using usePattern() method 
        matcher = matcher 
                      .usePattern( 
                          Pattern 
                              .compile(newPattern)); 
  
        // Get the Pattern 
        // using pattern method 
        System.out.println("New Pattern: "
                           + matcher.pattern()); 
    } 
}

输出：

Old Pattern: Geeks
New Pattern: GFG

示例2:

// Java code to illustrate usePattern() method 
  
import java.util.regex.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Get the regex to be checked 
        String regex = "GFG"; 
  
        // Create a pattern from regex 
        Pattern pattern 
            = Pattern.compile(regex); 
  
        // Get the String to be matched 
        String stringToBeMatched 
            = "GFGFGFGFGFGFGFGFGFG"; 
  
        // Create a matcher for the input String 
        Matcher matcher 
            = patter 
                  n.matcher(stringToBeMatched); 
  
        // Get the new Pattern 
        String newPattern = "Geeks"; 
  
        // Get the Pattern using pattern method 
        System.out.println("Old Pattern: "
                           + matcher.pattern()); 
  
        // Set the newPattern using usePattern() method 
        matcher = matcher 
                      .usePattern( 
                          Pattern 
                              .compile(newPattern)); 
  
        // Get the Pattern 
        // using pattern method 
        System.out.println("New Pattern: "
                           + matcher.pattern()); 
    } 
}

输出：

Old Pattern: GFG
New Pattern: Geeks

参考： Oracle Doc

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注：本文由纯净天空筛选整理自Kirti_Mangal大神的英文原创作品 Matcher usePattern(Pattern) method in Java with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。