ArrayList是List接口的实现,它属于java中的集合框架,它允许我们动态地(即在运行时)增加数组的大小。该类在java.util.package内部可用,它使用数组数据结构。 ArrayList只允许java中的包装类,用户定义类。
开始您的免费软件开发课程
网络开发、编程语言、软件测试及其他
语法:
ArrayList<T> list = new ArrayList<>();
List<T> list = new ArrayList<>();
我们可以直接使用ArrayList的实例或者将其分配给List引用。
构造函数:
在数组列表中,我们有三个可用的构造函数,如下:
以下是java ArrayList类的方法:
Examples of Java ArrayList Class are given below:
The below example will show how to add an element to an array list.
Code:
package com.cont.article; import java.util.ArrayList; public class ArratListTest { public static void main(String[] args) { ArrayList<String> list = new ArrayList<>(); list.add("abc"); list.add("xyz"); list.add("yyy"); list.add("some name"); list.add("other name"); System.out.println("list is :: " + list); } }
Output:
Code:
import java.util.ArrayList; public class Main { public static void main(String[] args) { ArrayList<String> list = new ArrayList<>(); list.add("abc"); list.add("xyz"); list.add("yyy"); list.add("some name"); list.add("other name"); ArrayList<String> list2 = new ArrayList<>(); list2.addAll(list); System.out.println("Elements in list one : " + list); System.out.println("Elements in list two : " + list2); } }
Output:
Code:
import java.util.ArrayList; public class Main { public static void main(String[] args) { ArrayList<String> list = new ArrayList<>(); list.add("abc"); list.add("xyz"); list.add("yyy"); list.add("some name"); list.add("other name"); System.out.println("Size of list before remove ::" + list.size()); System.out.println("Elements in list are before remove " + list); list.remove(4); System.out.println("Size of list after removinf element :: " +list.size()); System.out.println("Elements in list are after remove" + list); } }
Output:
Code:
import java.util.ArrayList; public class Main { public static void main(String[] args) { ArrayList<String> list = new ArrayList<>(); list.add("abc"); list.add("xyz"); list.add("yyy"); list.add("some name"); list.add("other name"); list.clear(); System.out.println("Clering all elements of list " +list.size()); } }
Output:
Code:
import java.util.ArrayList; public class Main { public static void main(String[] args) { ArrayList<String> list = new ArrayList<>(); list.add("abc"); list.add("xyz"); list.add("yyy"); list.add("some name"); list.add("other name"); System.out.println("Priniting out element."); for (String string : list) { System.out.println("Elemnt in the list is"); System.out.println(string); } } }
Output:
The array list in java does not contain duplicate elements. Also, the insertion order is maintained in a list, which means we put over elements that will generate the output in the same sequence. Some detailed points which need to be remembered for the array list in java are as follows:
It implements various interfaces:
The class hierarchy is as follows:
java.lang.Object >> java.util.AbstractCollection<E> >> java.util.AbstractList<E> >> java.util.ArrayList<E>
By default, the array list is not synchronized in nature and is not thread-safe, But we can make them synchronized using the collections class synchronized method. The syntax is described below for reference :
List arrList = Collections.synchronizedList (new ArrayList(...));
以上是Java ArrayList 类的详细内容。更多信息请关注PHP中文网其他相关文章!