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Java AbstractList addAll()用法及代码示例


java.util.AbstractList 类的 addAll() 方法用于将指定集合中的所有元素插入到此列表中的指定位置。

  • 这会将当前位于该位置的元素(如果有)和任何后续元素向右移动(增加它们的索引)。
  • 新元素将按照指定集合的​​迭代器返回的顺序出现在此列表中。
  • 如果在操作正在进行时修改了指定的集合，则此操作的行为是未定义的。

此实现在指定集合上获取一个迭代器并对其进行迭代，使用 add(int, E) 将从迭代器获得的元素插入到此列表中的适当位置，一次一个。许多实现将覆盖此方法以提高效率。

用法:

public boolean addAll(int index, Collection c)

参数：此方法将以下参数作为参数。

  • index-插入指定集合中第一个元素的索引
  • c-包含要添加到此列表的元素的集合

  • 返回值：如果此列表因调用而更改，则此方法返回 true。



  • Exception:此方法引发以下异常。
    • NullPointerException -如果指定的集合包含一个或多个空元素并且此列表不允许空元素，或者指定的集合为空
    • IndexOutOfBoundsException -如果索引超出范围(索引 size())。

以下是说明 addAll() 方法的示例。

范例1：


// Java program to demonstrate
// addAll() method
// for String value
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
  
        try {
  
            // Creating object of AbstractList<String>
            AbstractList<String>
                arrlist1 = new ArrayList<String>();
  
            // Populating arrlist1
            arrlist1.add("A");
            arrlist1.add("B");
            arrlist1.add("C");
            arrlist1.add("D");
            arrlist1.add("E");
  
            // print arrlist1
            System.out.println("Original ArrayListlist:"
                               + arrlist1);
  
            // Creating another object of AbstractList<String>
            AbstractList<String>
                arrlist2 = new ArrayList<String>();
  
            // Populating arrlist2
            arrlist2.add("X");
            arrlist2.add("Y");
            arrlist2.add("Z");
  
            // print arrlist2
            System.out.println("ArrayList elements "
                               + "to be added:"
                               + arrlist2);
  
            // adding the specified element
            // starting from index 2
            // using addAll() method
            boolean value = arrlist1.addAll(2, arrlist2);
  
            // print the value
            System.out.println("Operation successful:"
                               + value);
  
            // print the new arrlist
            System.out.println("New ArrayList:"
                               + arrlist1);
        }
  
        catch (NullPointerException e) {
            System.out.println("Exception thrown:" + e);
        }
  
        catch (IndexOutOfBoundsException e) {
            System.out.println("Exception thrown:" + e);
        }
    }
}
输出：
Original ArrayListlist:[A, B, C, D, E]
ArrayList elements to be added:[X, Y, Z]
Operation successful:true
New ArrayList:[A, B, X, Y, Z, C, D, E]

范例2：对于 NullPointerException


// Java program to demonstrate
// addAll() method
// for NullPointerException
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv) throws Exception
    {
        try {
  
            // Creating object of AbstractList<String>
            AbstractList<String>
                arrlist1 = new ArrayList<String>();
  
            // Populating arrlist1
            arrlist1.add("A");
            arrlist1.add("B");
            arrlist1.add("C");
            arrlist1.add("D");
            arrlist1.add("E");
  
            // print arrlist1
            System.out.println("Original ArrayListlist:"
                               + arrlist1);
  
            // Creating another object of AbstractList<String>
            AbstractList<String> arrlist2 = null;
  
            // printing the arrlist2
            System.out.println("ArrayList to be added:"
                               + arrlist2);
  
            // adding the specified element
            // starting from index 2
            // using addAll() method
            System.out.println("\nTrying to get"
                               + " the null collection");
            boolean value = arrlist1.addAll(2, arrlist2);
  
            // print the value
            System.out.println("operation successful:"
                               + value);
  
            // print the new arrlist
            System.out.println("New ArrayList:"
                               + arrlist1);
        }
  
        catch (NullPointerException e) {
            System.out.println("Exception thrown:" + e);
        }
  
        catch (IndexOutOfBoundsException e) {
            System.out.println("Exception thrown:" + e);
        }
    }
}
输出：
Original ArrayListlist:[A, B, C, D, E]
ArrayList to be added:null

Trying to get the null collection
Exception thrown:java.lang.NullPointerException

范例3：对于 IndexOutOfBoundsException


// Java program to demonstrate
// addAll() method
// for IndexOutOfBoundsException
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
  
        try {
  
            // Creating object of AbstractList<String>
            AbstractList<String>
                arrlist1 = new ArrayList<String>();
  
            // Populating arrlist1
            arrlist1.add("A");
            arrlist1.add("B");
            arrlist1.add("C");
            arrlist1.add("D");
            arrlist1.add("E");
  
            // print arrlist1
            System.out.println("Original ArrayListlist:"
                               + arrlist1);
  
            // Creating another object of AbstractList<String>
            AbstractList<String>
                arrlist2 = new ArrayList<String>();
  
            // Populating arrlist2
            arrlist2.add("X");
            arrlist2.add("Y");
            arrlist2.add("Z");
  
            // print arrlist2
            System.out.println("ArrayList elements to be added:"
                               + arrlist2);
  
            // adding the specified element
            // starting from index 2
            // using addAll() method
            System.out.println("\nTrying to put the out"
                               + " of range index ");
            boolean value = arrlist1.addAll(-1, arrlist2);
  
            // print the value
            System.out.println("operation succecfull:"
                               + value);
  
            // print the new arrlist
            System.out.println("New ArrayList:" + arrlist1);
        }
  
        catch (NullPointerException e) {
            System.out.println("Exception thrown:" + e);
        }
  
        catch (IndexOutOfBoundsException e) {
            System.out.println("Exception thrown:" + e);
        }
    }
}
输出：
Original ArrayListlist:[A, B, C, D, E]
ArrayList elements to be added:[X, Y, Z]

Trying to put the out of range index 
Exception thrown:java.lang.IndexOutOfBoundsException:Index:-1, Size:5




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