Java_基础—List集合的特有功能概述和测试

package com.soar.list;

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

@SuppressWarnings({ "rawtypes", "unused","unchecked" })
public class Demo1_List {
    /*
        * * A:List集合的特有功能概述
        * void add(int index,E element)
        * E remove(int index)
        * E get(int index)
        * E set(int index,E element)
    */

    public static void main(String[] args) {
        //add();
        //remove();
        //demo_remove();
        //bianLi();
        //set();
    }

    private static void set() {
        List list = new ArrayList();
        list.add("a");
        list.add("b");
        list.add("c");
        list.add("d");

        list.set(1, "z");       //将指定位置的元素进行修改
        System.out.println(list);   //[a, z, c, d]
    }

    private static void bianLi() {
        List list = new ArrayList();
        list.add("a");
        list.add("b");
        list.add("c");
        list.add("d");

        //Object obj1 = list.get(2);
        //System.out.println(obj1);
        //通过索引遍历List集合
        for (int i = 0; i < list.size(); i++) {
            System.out.println(list.get(i));
        }
    }

    private static void demo_remove() {
        List list = new ArrayList();
        list.add(111);
        list.add(222);
        list.add(333);

        list.remove(111);   //删除的时候不会自动装箱，把111当作索引
        System.out.println(list);   //删除时出现错误 Index: 111, Size: 3
    }

    private static void remove() {
        List list = new ArrayList();
        list.add("a");
        list.add("b");
        list.add("c");
        list.add("d");

        Object obj = list.remove(1);    //通过索引删除元素，将被删除的元素返回
        System.out.println(obj);
        System.out.println(list);
    }

    private static void add() {
        List list = new ArrayList();
        list.add("a");
        list.add("b");
        list.add("c");
        list.add("d");
        //list.add(1,"e");  
        //System.out.println(list); //[a, e, b, c, d]
        //list.add(10,"z");
        //System.out.println(list); //当存储时使用不存在的索引时就会出现索引异常
        list.add(4,"f");        //index <= size 并且 index>=0 都不会报异常
        System.out.println(list);
    }

}