Java中的 CopyOnWriteArrayList clear() 方法

CopyOnWriteArrayList的clear()方法擦除列表中的所有元素。调用函数后列表的大小变为零。

句法：

public void clear()

参数：该函数不接受任何参数。

返回值：该函数不返回任何内容。

下面的程序说明了上述函数：

方案一：

// Java Program to illustrate the CopyOnWriteArrayList
// clear() method in Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList ArrLis
            = new CopyOnWriteArrayList();
  
        // Add elements
        ArrLis.add(32);
        ArrLis.add(67);
        ArrLis.add(98);
        ArrLis.add(100);
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: " 
                                            + ArrLis);
  
        ArrLis.clear();
  
        System.out.println("CopyOnWriteArrayList: " 
                                         + ArrLis);
    }
}

输出：

CopyOnWriteArrayList: [32, 67, 98, 100]
CopyOnWriteArrayList: []

方案二：

// Java Program to illustrate the CopyOnWriteArrayList
// clear() method in Java
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.*;
  
public class GFG {
    public static void main(String[] args)
    {
  
        // create object of CopyOnWriteArrayList
        CopyOnWriteArrayList ArrLis
            = new CopyOnWriteArrayList();
  
        // Add elements
        ArrLis.add("gopal");
        ArrLis.add("gfg");
        ArrLis.add("jgec");
        ArrLis.add("sudo");
  
        // print CopyOnWriteArrayList
        System.out.println("CopyOnWriteArrayList: " 
                                          + ArrLis);
  
        ArrLis.clear();
  
        System.out.println("CopyOnWriteArrayList: " 
                                         + ArrLis);
    }
}

输出：

CopyOnWriteArrayList: [gopal, gfg, jgec, sudo]
CopyOnWriteArrayList: []

参考： https: Java/util/concurrent/CopyOnWriteArrayList.html#clear–