List与数组相互转换

一：ArrayList的遍历

import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;


/**
 * ArrayList的遍历
 */
public class Test {
    public static void main(String[] args) {
        List<Integer> list = new ArrayList<>();
        list.add(5);
        list.add(6);
        list.add(7);
        list.add(8);
        list.add(9);

        //1.直接输出
        System.out.print(list);
        System.out.println();

        //2.for循环
        for (int i = 0; i < list.size(); i++) {
            System.out.print(list.get(i) + " ");
        }
        System.out.println();

        //3.foreach遍历
        for (int x : list) {
            System.out.print(x + " ");
        }
        System.out.println();

        //4.使用迭代器遍历
        Iterator<Integer> it1 = list.listIterator();
        while (it1.hasNext()) {
            System.out.print(it1.next() + " ");
        }
        System.out.println();
    }
}

二：LinkedList的遍历

import java.util.LinkedList;
import java.util.ListIterator;

public class Test {
    public static void main(String[] args) {
        LinkedList<Integer> list=new LinkedList<>();
        list.add(1);
        list.add(2);
        list.add(3);
        list.add(4);
        list.add(5);

        //1.直接输出:因为重写了toString()
        System.out.print(list);
        System.out.println();

        //2.foreach遍历
        for (int x:list) {
            System.out.print(x+" ");
        }
        System.out.println();

        //3.使用迭代器遍历——正向遍历
        ListIterator<Integer> it1= list.listIterator();
        while(it1.hasNext()){
            System.out.print(it1.next()+" ");
        }
        System.out.println();

        //4.使用反向迭代器遍历——反向遍历
        ListIterator<Integer> it2= list.listIterator(list.size());
        while(it1.hasPrevious()){
            System.out.print(it1.previous()+" ");
        }
        System.out.println();
    }
}