Java Scanner 讀取鍵盤輸入存入 ArrayList 完整教學

基本範例

import java.util.*;

public class InputToList {
    public static void main(String[] args) {
        List list = new ArrayList<>();
        Scanner sc = new Scanner(System.in);

        System.out.println("請輸入資料 (輸入 end 結束)：");
        while (sc.hasNext()) {
            String input = sc.next(); // 以空白分隔
            if ("end".equalsIgnoreCase(input)) break;
            list.add(input);
        }

        System.out.println("您輸入的資料：" + list);
        sc.close();
    }
}

進階：逐行讀取 (保留空白)

while (sc.hasNextLine()) {
    String line = sc.nextLine();
    if ("end".equalsIgnoreCase(line.trim())) break;
    list.add(line); // 保留整行包含空白
}

型別轉換：輸入數字存入 List

List nums = new ArrayList<>();
while (sc.hasNextInt()) {
    nums.add(sc.nextInt());
}
// 遇到非整數會停止，需搭配 hasNext() 清理緩衝區

常見坑與解法

完整可執行範例 (含 try-with-resources)

public class Demo {
    public static void main(String[] args) {
        try (Scanner sc = new Scanner(System.in)) {
            List list = new ArrayList<>();
            System.out.print("> ");
            while (sc.hasNext()) {
                String s = sc.next();
                if ("quit".equalsIgnoreCase(s)) break;
                list.add(s);
                System.out.print("> ");
            }
            System.out.println("結果: " + list);
        }
    }
}