Java中的 CopyOnWriteArrayList containsAll() 方法

Java中 CopyOnWriteArrayList 类的 containsAll() 方法用于检查此 List 是否包含指定 Collection 中的所有元素。所以基本上它用于检查 List 是否包含一组元素。

语法：

boolean containsAll(Collection col)

参数：此方法接受一个强制参数 col，该参数属于集合类型。这是需要检查其元素是否存在于列表中的集合。

返回值：如果集合 col 中的所有元素都存在于 List 中，则该方法返回 True，否则返回 False。

异常：如果指定的集合为 NULL，该方法将抛出 NullPointerException。

下面的程序说明了 CopyOnWriteArrayList 类的 containsAll() 方法：

程序 1 ：

// Java program to illustrate CopyOnWriteArrayList
//  containsAll() method
  
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
  
public class GFG1 {
    public static void main(String[] args)
    {
        CopyOnWriteArrayList ArrLis1
            = new CopyOnWriteArrayList();
  
        // Add elements
        ArrLis1.add("geeks");
        ArrLis1.add("shaan");
        ArrLis1.add("gfg");
        ArrLis1.add("programming");
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList1: " + ArrLis1);
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList ArrLis2
            = new CopyOnWriteArrayList();
  
        // Add elements
        ArrLis2.add("geeks");
        ArrLis2.add("gfg");
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList2: " + ArrLis2);
  
        // check using function
        if (ArrLis1.containsAll(ArrLis2))
            System.out.println("All list2 elements are present in list1");
        else
            System.out.println("All list2 elements are not present in list1");
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList ArrLis3
            = new CopyOnWriteArrayList();
  
        // Add elements
        ArrLis3.add("geeks");
        ArrLis3.add("qwe");
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList3: " + ArrLis3);
  
        // check using function
        if (ArrLis1.containsAll(ArrLis3))
            System.out.println("All list3 elements are present in list1");
        else
            System.out.println("All list3 elements are not present in list1");
    }
}

输出：

CopyOnWriteArrayList1: [geeks, shaan, gfg, programming]
CopyOnWriteArrayList2: [geeks, gfg]
All list2 elements are present in list1
CopyOnWriteArrayList3: [geeks, qwe]
All list3 elements are not present in list1

方案二：

// Java program to illustrate CopyOnWriteArrayList
// containsAll() method
  
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
  
public class GFG1 {
    public static void main(String[] args)
    {
        CopyOnWriteArrayList ArrLis1
            = new CopyOnWriteArrayList();
  
        // Add elements
        ArrLis1.add(23);
        ArrLis1.add(65);
        ArrLis1.add(91);
        ArrLis1.add(126);
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList1: " + ArrLis1);
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList ArrLis2
            = new CopyOnWriteArrayList();
  
        // Add elements
        ArrLis2.add(23);
        ArrLis2.add(126);
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList2: " + ArrLis2);
  
        // check using function
        if (ArrLis1.containsAll(ArrLis2))
            System.out.println("All list2 elements are present in list1");
        else
            System.out.println("All list2 elements are not present in list1");
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList ArrLis3
            = new CopyOnWriteArrayList();
  
        // Add elements
        ArrLis3.add(23);
        ArrLis3.add(92);
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList3: " + ArrLis3);
  
        // check using function
        if (ArrLis1.containsAll(ArrLis3))
            System.out.println("All list3 elements are present in list1");
        else
            System.out.println("All list3 elements are not present in list1");
    }
}

输出：

CopyOnWriteArrayList1: [23, 65, 91, 126]
CopyOnWriteArrayList2: [23, 126]
All list2 elements are present in list1
CopyOnWriteArrayList3: [23, 92]
All list3 elements are not present in list1

参考：https: Java Java.util.Collection)