优化这段代码public class DataIO { public static void savePersonList(List<Person> list, String fileName) throws IOException { ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(fileName)); oos.writeObject(list); oos.close(); } public static List<Person> loadPersonList(String fileName) throws IOException, ClassNotFoundException { ObjectInputStream ois = new ObjectInputStream(new FileInputStream(fileName)); List<Person> list = (List<Person>) ois.readObject(); ois.close(); return list; } }使其能够输出保存成功，保存失败，读入成功，读入失败的System

可以在方法中添加try-catch语句，捕获异常并输出对应的信息。修改后的代码如下：

public class DataIO {
    public static void savePersonList(List<Person> list, String fileName) {
        try {
            ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(fileName));
            oos.writeObject(list);
            oos.close();
            System.out.println("保存成功！");
        } catch (IOException e) {
            System.out.println("保存失败！");
            e.printStackTrace();
        }
    }

    public static List<Person> loadPersonList(String fileName) {
        try {
            ObjectInputStream ois = new ObjectInputStream(new FileInputStream(fileName));
            List<Person> list = (List<Person>) ois.readObject();
            ois.close();
            System.out.println("读入成功！");
            return list;
        } catch (IOException | ClassNotFoundException e) {
            System.out.println("读入失败！");
            e.printStackTrace();
            return new ArrayList<>();
        }
    }
}

这样，在保存和读取文件时，若出现异常，就会输出对应的信息。如果保存成功或读取成功，则也会输出对应的信息。