使用Windows IoT在Raspberry PI上保存文件-Java 学习之路

我有一个关于使用Windows IoT在Raspberry PI上保存文件的问题 .

我想做什么：我有各种值（温度），我想记录 . 对我来说最简单的方法是编写一个包含所有值的简单txt文件 .

首先：甚至可以在SD卡上本地创建文件吗？因为我发现的代码示例只适用于“普通”Windows系统：

if (!File.Exists(path))
    {
        // Create a file to write to.
        string createText = "Hello and Welcome" + Environment.NewLine;
        File.WriteAllText(path, createText);
    }

或在Windows Phone上：

public void createdirectory()
    {
        IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication();
        myIsolatedStorage.CreateDirectory("TextFilesFolder");
        filename = "TextFilesFolder\\Samplefile.txt";
        Create_new_file();
    }

    public void Create_new_file()
    {
        IsolatedStorageFile myIsolatedStorage = IsolatedStorageFile.GetUserStoreForApplication();

        if (!myIsolatedStorage.FileExists(filename))
        {
            using (StreamWriter writeFile = new StreamWriter(new IsolatedStorageFileStream(filename, FileMode.Create, FileAccess.Write, myIsolatedStorage)))
            {
                string someTextData = "This is a test!";
                writeFile.WriteLine(someTextData);
               // writeFile.Close();
            }
        }

Windows Phone的代码对我来说更有意义 . （另一方面根本不起作用） . 但即使电话代码是正确的，我也不知道如何访问内部存储 . 我已经尝试过IsolatedStorageExplorerTool，但它无法识别我的设备 . 可能是因为我的设备没有连接USB ......而且它不是手机 . 当我使用SSH时，我也找不到该目录 .

也许有人有个主意 . 提前感谢您的帮助！

2 回答

2

没关系，我找到了解决方案 . 这是Windows手机的代码 . 2.您必须使用Windows IoT核心观察程序 . 右键单击您的设备并打开网络共享 . 之后我找到了文本文件：\ c $ \ Users \ DefaultAccount \ AppData \ Local \ Packages \ LocalState \ TextFilesFolder

回复于 2024-05-19T06:08:44+08:00

您可以将序列化用于有组织的存储而不是文本存储 .

我正在附加静态类文件，其中包含序列化和反序列化回原始对象的方法 .

Download Source Code

我们来看一个概括性的例子 . 假设您有Student和Mark课程，如下所示：

/// <summary>
/// Provides structure for 'Student' entity
/// </summary>
/// 'DataContract' attribute is necessary to serialize object of following class. By removing 'DataContract' attribute, the following class 'Student' will no longer be serialized
[DataContract]
public class Student
{
    [DataMember]
    public ushort Id { get; set; }

    [DataMember]
    public string UserName { get; set; }

    /// <summary>
    /// Password has been marked as non-serializable by removing 'DataContract'
    /// </summary>
    // [DataMember] // Password will not be serialized. Uncomment this line to serialize password
    public string Password { get; set; }

    [DataMember]
    public string FirstName { get; set; }

    [DataMember]
    public string LastName { get; set; }

    [DataMember]
    public List<Mark> Marks { get; set; }
}

[DataContract]
public class Mark
{
    [DataMember]
    public string Subject { get; set; }

    [DataMember]
    public short Percentage { get; set; }
}

确保在calss上定义'[DataContract]'，在数据成员上定义'[DataMember]'以序列化它们，否则在序列化对象时它们将被忽略

现在，为了序列化和反序列化，您将拥有以下带保存和加载功能的静态类：

/// <summary>
/// Provides functions to save and load single object as well as List of 'T' using serialization
/// </summary>
/// <typeparam name="T">Type parameter to be serialize</typeparam>
public static class SerializableStorage<T> where T : new()
{
    public static async void Save(string FileName, T _Data)
    {
        MemoryStream _MemoryStream = new MemoryStream();
        DataContractSerializer Serializer = new DataContractSerializer(typeof(T));
        Serializer.WriteObject(_MemoryStream, _Data);

        Task.WaitAll();

        StorageFile _File = await ApplicationData.Current.LocalFolder.CreateFileAsync(FileName, CreationCollisionOption.ReplaceExisting);

        using (Stream fileStream = await _File.OpenStreamForWriteAsync())
        {
            _MemoryStream.Seek(0, SeekOrigin.Begin);
            await _MemoryStream.CopyToAsync(fileStream);
            await fileStream.FlushAsync();
            fileStream.Dispose();
        }
    }

    public static async Task<T> Load(string FileName)
    {
        StorageFolder _Folder = ApplicationData.Current.LocalFolder;
        StorageFile _File;
        T Result;

        try
        {
            Task.WaitAll();
            _File = await _Folder.GetFileAsync(FileName);

            using (Stream stream = await _File.OpenStreamForReadAsync())
            {
                DataContractSerializer Serializer = new DataContractSerializer(typeof(T));

                Result = (T)Serializer.ReadObject(stream);

            }
            return Result;
        }
        catch (Exception ex)
        {
            return new T();
        }
    }
}

现在，让我们看看如何存储学生的对象并从文件中检索它：

/* Create an object of Student class to store */
Student s1 = new Student();
s1.Id = 1;
s1.UserName = "Student1";
s1.Password = "Student123";
s1.FirstName = "Abc";
s1.LastName = "Xyz";
s1.Marks = new List<Mark>();

/* Create list of Marks */
Mark m1 = new Mark();
m1.Subject = "Computer";
m1.Percentage = 89;

Mark m2 = new Mark();
m2.Subject = "Physics";
m2.Percentage = 92;

/* Add marks into Student object */
s1.Marks.Add(m1);
s1.Marks.Add(m2);

/* Store Student object 's1' into file 'MyFile1.dat' */
SerializableStorage<Student>.Save("MyFile1.dat", s1);

/* Load stored student object from 'MyFile1.dat' */
Student s2 = await SerializableStorage<Student>.Load("MyFile1.dat");

您可以序列化和反序列化任何类 . 要存储'Student'以外的类的对象，假设'MyClass'，只需从函数的'T'参数替换Student类型，如下所示：

/* Store MyClass object 's1' into file 'MyFile1.dat' */
SerializableStorage<MyClass>.Save("MyFile1.dat", s1);

/* Load stored MyClass object from 'MyFile1.dat' */
MyClass s2 = await SerializableStorage<MyClass>.Load("MyFile1.dat");

注意：'MyFile1.dat'将存储在'ApplicationData.Current.LocalFolder'中 . 此代码在Windows 10 IoT Core（10.0.10586.0）上进行测试，可以在任何UWP应用程序上运行 .

Download Source Code

回复于 2024-05-19T06:08:44+08:00

使用Windows IoT在Raspberry PI上保存文件

2 回答

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