Java PatternSyntaxException getIndex()用法及代码示例

Java PatternSyntaxException 类在 java.util.regex 包下定义，它说明了表示正则表达式模式中的语法错误的未经检查的异常。可以使用以下语法声明此类，

public class PatternSyntaxException extends IllegalArgumentException

PatternSyntaxException::getIndex()

此方法用于检索作为异常抛出的错误的索引。语法如下，

用法:

public int getIndex()

返回：它返回一个非负整数：如果无法检索索引，则错误模式中的索引为 -1

示例 1：在此示例中，错误位于模式中的索引 0 处。这是因为未封闭的字符。

Java


// Java program to illustrate the working of getIndex() method 
  
import java.io.*; 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
import java.util.regex.PatternSyntaxException; 
  
class GFG { 
    
    
   private static String regularExpression = "["; 
   private static String input = "GeeksforGeeks " + "is a learning platform."; 
   private static String replace = "Hi"; 
    
    public static void main (String[] args) { 
        
try{ 
         // Compile the pattern 
         Pattern pattern = Pattern.compile(regularExpression); 
           
         // To get a matcher object 
         Matcher matcher = pattern.matcher(input);  
         input = matcher.replaceAll(replace); 
      } catch(PatternSyntaxException e){ 
             
         // Print the index in the error of the pattern  
         System.out.println("Index: "+ e.getIndex()); 
         System.out.println("Message: "+ e.getMessage()); 
      } 
    } 
}

输出

Index: 0
Message: Unclosed character class near index 0
[
^

示例 2：在这个例子中，getIndex()方法返回-1。这是因为非法重复导致索引无法检索。

Java


// Java program to illustrate the working of getIndex() method 
  
import java.io.*; 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
import java.util.regex.PatternSyntaxException; 
  
class GFG { 
    
   // Declaring a string variable to store the regular expression  
   private static String regularExpression = "{"; 
   private static String input = "GeeksforGeeks " + "is a learning platform."; 
   private static String replace = "Hello"; 
    
    public static void main (String[] args) { 
        
         try{ 
            
         // Compile the pattern 
         Pattern pattern = Pattern.compile(regularExpression); 
           
         // To get a matcher object 
         Matcher matcher = pattern.matcher(input);  
         input = matcher.replaceAll(replace); 
      } catch(PatternSyntaxException e){ 
           
         // Print the index in the error of the pattern  
         System.out.println("Index: "+ e.getIndex()); 
         System.out.println("Message: "+ e.getMessage()); 
      } 
    } 
}

输出

Index: -1
Message: Illegal repetition
{

相关用法

注：本文由纯净天空筛选整理自bhuwanesh大神的英文原创作品 Java PatternSyntaxException Class getIndex() Method 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。