Java PatternSyntaxException getIndex()用法及代碼示例

Java PatternSyntaxException 類在 java.util.regex 包下定義，它說明了表示正則表達式模式中的語法錯誤的未經檢查的異常。可以使用以下語法聲明此類，

public class PatternSyntaxException extends IllegalArgumentException

PatternSyntaxException::getIndex()

此方法用於檢索作為異常拋出的錯誤的索引。語法如下，

用法:

public int getIndex()

返回：它返回一個非負整數：如果無法檢索索引，則錯誤模式中的索引為 -1

示例 1：在此示例中，錯誤位於模式中的索引 0 處。這是因為未封閉的字符。

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()); 
      } 
    } 
}

輸出

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

示例 2：在這個例子中，getIndex()方法返回-1。這是因為非法重複導致索引無法檢索。

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()); 
      } 
    } 
}

輸出

Index: -1
Message: Illegal repetition
{

相關用法

注：本文由純淨天空篩選整理自bhuwanesh大神的英文原創作品 Java PatternSyntaxException Class getIndex() Method with Examples。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。