List的ListIterator學習筆記

今天看書，看到書上介紹ListIterator的remove()，我想了解一下，編寫了以下代碼。

package com.sunhang;

import java.util.*;

public class Main {

    private static <T> void print(T t){
        System.out.println(t);
    }

    private List<String> generateList(){
        List<String> list = new LinkedList<String>();
        String[] arr = "hello how are you are you ok fine thank you".split(" ");
        for (int i = 0; i < arr.length; i ++){
            list.add(String.format("[%d:%s]", i, arr[i]));
        }

        return list;
    }

    private void test0(){
        print("test0 ======================");

        List<String> list = generateList();
        print(list);

        ListIterator<String> it = list.listIterator(5);
        while(it.hasNext()){
            it.next();
            it.remove();
        }

        print(list);
    }

    private void test1(){
        print("test1 ======================");

        List<String> list = generateList();
        print(list);

        ListIterator<String> it = list.listIterator(5);
        while(it.hasPrevious()){
            it.previous();
            it.remove();
        }

        print(list);
    }

    private void test2(){
        List<String> list = generateList();
        print(list);

        ListIterator<String> it = list.listIterator(5);
        it.remove();    // 此處會拋出異常

        print(list);
    }

    public static void main(String[] args){
        Main main = new Main();
        main.test0();
        main.test1();
//        main.test2();    // test2會拋出異常
    }
}

查看輸出結果：

test0 ======================

[[0:hello], [1:how], [2:are], [3:you], [4:are], [5:you], [6:ok], [7:fine], [8:thank], [9:you]]

[[0:hello], [1:how], [2:are], [3:you], [4:are]]

test1 ======================

[[0:hello], [1:how], [2:are], [3:you], [4:are], [5:you], [6:ok], [7:fine], [8:thank], [9:you]]

[[5:you], [6:ok], [7:fine], [8:thank], [9:you]]