ArrayList和Array数组类型转换

package com.Mxhlin.arrayList;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * @author Mxhlin
 * @Email [email protected]
 * @Date 2022/09/19/21:01
 * @Version
 * @Description ArrayList和Array数组类型转换
 */
public class ArrayListOrArray {
    public static void main(String[] args) {
        Integer[] in = new Integer[]{10,20,30,40,50,60,70};

        List<Integer> list = Arrays.asList(in);
        List<Integer> list1 = List.of(1, 2, 3);
        System.out.println(list.size());// 7
        System.out.println(list1.size());// 3
        // list.clear();// 异常
        // list1.clear();// 异常


        // 数组 -> List
        ArrayList list3 = new ArrayList(list);
        System.out.println(list3.size());// 7
        list3.add(500);
        list3.addAll(List.of(900,800,700));
        System.out.println(list3.size());// 11
        System.out.println(list3);// [10, 20, 30, 40, 50, 60, 70, 500, 900, 800, 700]
        System.out.println(Arrays.toString(in));// [10, 20, 30, 40, 50, 60, 70]

        // List -> 数组
        Object[] array = list3.toArray();
        System.out.println(array.length);// 11
        // for (Object o : array) {
        //     System.out.println(o);
        // }
        // 数组 -> List
        Integer[] integers = {100, 200, 300};
        ArrayList<Integer> list4 = new ArrayList<>(Arrays.asList(integers));
        System.out.println(list4.size());// 3
        System.out.println(list4);// [100, 200, 300]

        // List -> Array
        List<String> list5 = new ArrayList<>();
        list5.addAll(List.of("springmvc","java","springboot"));
        System.out.println(list5.size());// 3
        // 删除指定字符串
        list5.remove("java");
        System.out.println(list5.size());// 2
        // Object[] objects = list5.toArray();
        // String string = Arrays.toString(objects);
        // System.out.println(string);

        String[] ss = new String[list5.size()];
        String[] strings = list5.toArray(ss);
        for (String string : strings) {
            System.out.println(string);// springmvc springboot
        }
        System.out.println(strings.length);// 2
    }
}