Java CopyOnWriteArrayList removeAll()用法及代码示例

CopyOnWriteArrayList类中的removeAll()方法可从调用的CopyOnArrayList对象中删除指定集合中包含的所有元素。

用法:

public boolean removeAll(Collection collection)

参数：该方法仅接受要从调用对象中删除的单个参数集合。

返回值：此方法返回一个布尔值。如果此删除操作成功，则返回true。

异常：此方法引发以下异常：

ClassCastException：如果此列表的元素的类与指定的集合不兼容。
NullPointerException ：如果指定的集合为null，或者此列表包含null元素，并且指定的集合不允许使用null元素。

以下示例说明了removeAll()方法：

范例1：

// Java program to demonstrate removeAll() method 
  
import java.util.ArrayList; 
import java.util.concurrent.CopyOnWriteArrayList; 
  
public class Demo { 
  
    public static void main(String args[]) 
    { 
  
        // Get the CopyOnWriteArrayList 
        CopyOnWriteArrayList<String> wishlist 
            = new CopyOnWriteArrayList<>(); 
  
        // Add the elements in the CopyOnWriteArrayList 
        wishlist.add("TV"); 
        wishlist.add("computer"); 
        wishlist.add("play station"); 
        wishlist.add("mobile"); 
        wishlist.add("smart watch"); 
  
        // Print the CopyOnWriteArrayList 
        System.out.println("CopyOnWriteArrayList:\n"
                           + wishlist); 
  
        // Get the collection to be removed 
        ArrayList<String> checkList 
            = new ArrayList<>(); 
  
        checkList.add("play station"); 
        checkList.add("TV"); 
        checkList.add("mobile"); 
  
        System.out.println("\nCollection to be removed:\n"
                           + checkList); 
  
        // Remove the collection from CopyOnWriteArrayList 
        // using removeAll() method 
        wishlist.removeAll(checkList); 
  
        // Print the CopyOnWriteArrayList after removal 
        System.out.println("\nAfter removal of collection"
                           + " from CopyOnWriteArrayList:\n"
                           + wishlist); 
    } 
}

输出：

CopyOnWriteArrayList:
[TV, computer, play station, mobile, smart watch]

Collection to be removed:
[play station, TV, mobile]

After removal of collection from CopyOnWriteArrayList:
[computer, smart watch]

范例2：显示NullPointerException

// Java program to demonstrate removeAll() method 
  
import java.util.ArrayList; 
import java.util.concurrent.CopyOnWriteArrayList; 
  
public class Demo { 
  
    public static void main(String args[]) 
    { 
  
        // Get the CopyOnWriteArrayList 
        CopyOnWriteArrayList<String> wishlist 
            = new CopyOnWriteArrayList<>(); 
  
        // Add the elements in the CopyOnWriteArrayList 
        wishlist.add("TV"); 
        wishlist.add("computer"); 
        wishlist.add("play station"); 
        wishlist.add("mobile"); 
        wishlist.add("smart watch"); 
  
        // Print the CopyOnWriteArrayList 
        System.out.println("CopyOnWriteArrayList:\n"
                           + wishlist); 
  
        // Get the collection to be removed 
        ArrayList<String> checkList 
            = null; 
        System.out.println("\nCollection to be removed:"
                           + checkList); 
  
        try { 
  
            // Remove the collection from CopyOnWriteArrayList 
            // using removeAll() method 
            wishlist.removeAll(checkList); 
        } 
        catch (Exception e) { 
  
            // Print the Exception 
            System.out.println("\nException thrown"
                               + " while removing null "
                               + "from the CopyOnWriteArrayList:\n"
                               + e); 
        } 
    } 
}

输出：

CopyOnWriteArrayList:
[TV, computer, play station, mobile, smart watch]

Collection to be removed:null

Exception thrown while removing null from the CopyOnWriteArrayList:
java.lang.NullPointerException

相关用法

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