Java ArrayList listIterator()用法及代码示例

listIterator()

java.util.ArrayList类的listIterator()方法用于返回此列表中的元素的列表迭代器(按适当顺序)。返回的列表迭代器为fail-fast。

用法:

public ListIterator listIterator()

返回值：此方法返回该列表中的元素的列表迭代器(按适当顺序)。

以下示例说明了listIterator()方法。

示例1:

// Java program to demonstrate 
// listIterator() method 
// for String value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // Creating object of ArrayList<Integer> 
            ArrayList<String> 
                arrlist = new ArrayList<String>(); 
  
            // adding element to arrlist 
            arrlist.add("A"); 
            arrlist.add("B"); 
            arrlist.add("C"); 
            arrlist.add("D"); 
  
            // print arrlist 
            System.out.println("ArrayList: "
                               + arrlist); 
  
            // Creating object of ListIterator<String> 
            // using listIterator() method 
            ListIterator<String> 
                iterator = arrlist.listIterator(); 
  
            // Printing the iterated value 
            System.out.println("\nUsing ListIterator:\n"); 
            while (iterator.hasNext()) { 
                System.out.println("Value is : "
                                   + iterator.next()); 
            } 
        } 
  
        catch (NullPointerException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

ArrayList: [A, B, C, D]

Using ListIterator:

Value is : A
Value is : B
Value is : C
Value is : D

listIterator(int index)

此方法用于从列表中的指定位置开始(按适当顺序)返回列表中元素的列表迭代器。指定的索引指示首次调用next将返回的第一个元素。最初调用previous将返回指定索引减一的元素。返回的列表迭代器为fail-fast。

用法:

public ListIterator listIterator(int index)

参数：此方法将第一个元素的索引作为要从列表迭代器返回的参数(通过调用next)

返回值：此方法从列表中的指定位置开始(按适当顺序)返回列表中元素的列表迭代器。

异常：如果索引超出范围(索引size())，则此方法将引发IndexOutOfBoundsException。

以下示例说明了listIterator()方法。

示例1:

// Java program to demonstrate 
// listIterator() method 
// for String value 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // Creating object of ArrayList<Integer> 
            ArrayList<String> arrlist = new ArrayList<String>(); 
  
            // adding element to arrlist 
            arrlist.add("A"); 
            arrlist.add("B"); 
            arrlist.add("C"); 
            arrlist.add("D"); 
  
            // print arrlist 
            System.out.println("ArrayList: "
                               + arrlist); 
  
            // getting iterated value starting from index 2 
            // using listIterator() method 
            ListIterator<String> 
                iterator = arrlist.listIterator(2); 
  
            // Printing the iterated value 
            System.out.println("\nUsing ListIterator"
                               + " from Index 2:\n"); 
            while (iterator.hasNext()) { 
                System.out.println("Value is : "
                                   + iterator.next()); 
            } 
        } 
  
        catch (IndexOutOfBoundsException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

ArrayList: [A, B, C, D]

Using ListIterator from Index 2:

Value is : C
Value is : D

示例2:对于IndexOutOfBoundsException

// Java program to demonstrate 
// listIterator() method 
// for IndexOutOfBoundsException 
  
import java.util.*; 
  
public class GFG1 { 
    public static void main(String[] argv) throws Exception 
    { 
        try { 
  
            // Creating object of ArrayList<Integer> 
            ArrayList<String> 
                arrlist = new ArrayList<String>(); 
  
            // adding element to arrlist 
            arrlist.add("A"); 
            arrlist.add("B"); 
            arrlist.add("C"); 
            arrlist.add("D"); 
  
            // print arrlist 
            System.out.println("ArrayList: "
                               + arrlist); 
            System.out.println("Size of ArrayList: "
                               + arrlist.size()); 
  
            // Get ListIterator from index 7 
            // using listIterator() method 
            System.out.println("Trying to getListIterator"
                               + " from index 7\n"); 
  
            ListIterator<String> 
                iterator = arrlist.listIterator(7); 
        } 
  
        catch (IndexOutOfBoundsException e) { 
            System.out.println("Exception thrown : " + e); 
        } 
    } 
}

输出：

ArrayList: [A, B, C, D]
Size of ArrayList: 4
Trying to getListIterator from index 7

Exception thrown : java.lang.IndexOutOfBoundsException: Index: 7

相关用法

注：本文由纯净天空筛选整理自RohitPrasad3大神的英文原创作品 ArrayList listIterator() 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。