Java AbstractList clear()用法及代码示例

java.util.AbstractList 类的 clear() 方法用于从该列表中删除所有元素。此调用返回后，列表将为空。

用法:

public void clear()

返回值：此方法不返回任何内容。

以下是说明 clear() 方法的示例。

范例1：


// Java program to demonstrate
// clear() 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 the ArrayList
            System.out.println("Original ArrayListlist:"
                               + arrlist1);
  
            // Removing all the elements
            // using clear() method
            arrlist1.clear();
  
            // print the new ArrayList
            System.out.println("New ArrayList:"
                               + arrlist1);
        }
  
        catch (NullPointerException e) {
            System.out.println("Exception thrown:"
                               + e);
        }
    }
}

输出：

Original ArrayListlist:[A, B, C, D, E]
New ArrayList:[]

范例2：


// Java program to demonstrate
// clear() method
// for Integer value
  
import java.util.*;
  
public class GFG1 {
    public static void main(String[] argv)
        throws Exception
    {
  
        try {
  
            // Creating object of AbstractList<Integer>
            AbstractList<Integer>
                arrlist1 = new ArrayList<Integer>();
  
            // Populating arrlist1
            arrlist1.add(10);
            arrlist1.add(20);
            arrlist1.add(30);
            arrlist1.add(40);
            arrlist1.add(50);
  
            // print the ArrayList
            System.out.println("Original ArrayListlist:"
                               + arrlist1);
  
            // Removing all the elements
            // using clear() method
            arrlist1.clear();
  
            // print the new ArrayList
            System.out.println("New ArrayList:"
                               + arrlist1);
        }
  
        catch (NullPointerException e) {
            System.out.println("Exception thrown:" + e);
        }
    }
}

输出：

Original ArrayListlist:[10, 20, 30, 40, 50]
New ArrayList:[]

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 AbstractList clear() 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。