使用Stream对ArrayList进行操作。 结合IntStream来获取索引。 通过mapToObj方法将索引和元素组合。 代码示例 以下代码示例展示了如何使用Java的ArrayList和Stream获取元素的索引。 importjava.util.ArrayList;importjava.util.List;importjava.util.stream.IntStream;publicclassStreamIndexExample{publicstaticvoidmain(String[]a...
importjava.util.ArrayList;publicclassStreamArrayListExample{publicstaticvoidmain(String[]args){// 创建ArrayList对象ArrayList<String>list=newArrayList<>();// 添加数据list.add("Apple");list.add("Banana");list.add("Orange");// 使用Stream的forEach方法遍历ArrayList并输出list.stream().forEach(element->...
// Java program to convert Stream to ArrayList // using Collectors.toList() method importjava.util.*; importjava.util.stream.*; publicclassGFG{ // Function to get ArrayList from Stream publicstatic<T>ArrayList<T> getArrayListFromStream(Stream<T>stream) { // Convert the Stream to ArrayList ...
...如何在Java中将ArrayList转换为数组 (How to Convert ArrayList to Array in Java) 使用手动方式转换 (Convert Using Manual...在此方法中,我们将首先创建一个大小等于ArrayList大小的数组。 之后,使用get()方法获取 ArrayList的每个元素,然后将其复制到array中。 ...Array str=list.toArray(str); //pr...
Here’s an example of initializing an ArrayList using the Stream API: ArrayList<String>names=Stream.of("John","Alice").collect(Collectors.toCollection(ArrayList::new));System.out.println(names);#Output:#[John,Alice] Java Copy In this example,Stream.of("John", "Alice")creates a new stream...
Object[]toArray() Returns an array containing all of the elements in this list in proper sequence (from first to last element). <T> T[]toArray(T[] a) Returns an array containing all of the elements in this list in proper sequence (from first to last element); the runtime type of...
importjava.util.ArrayList;Copy Listrepresents an ordered sequence of values where some value may occur more than one time. ArrayListis one of theListimplementations built atop an array, which is able to dynamically grow and shrink as you add/remove elements. Elements could be easily accessed by...
}// 有参构造,指定一个已有的集合创建 ArrayList(原集合内的元素会添加到 新建的ArrayList中),此时 ArrayList的长度等于 传入的集合的长度publicArrayList(Collection<? extends E> c){// 将参数集合转为数组elementData = c.toArray();// 判断数组大小if((size = elementData.length) !=0) {// c.toArray...
import java.io.ByteArrayOutputStream; import java.util.ArrayList; public class ArrayListToStringBytes { public static void main(String[] args) { ArrayList<String> stringList = new ArrayList<>(); stringList.add("Hello"); stringList.add("World"); byte[] result = convertArrayListToBytes(string...
(1) public Object[] toArray()public Object[] toArray() { return Arrays.copyOf(elementData, size); } 此方法直接调用Arrays.copyof() 并将结果返回,这样做有潜在危机,有可能会抛出ClassCastException异常。例如:直接用向下转型的方法,将整个ArrayList集合转变为指定类型的Array数组,便会抛出该异常。但是,...