创建文件夹StreamingAssets,将字符123/n456/n789/n写入文件test.txt。然后把文件转换为byte数组发给服务端。再把文件里的数据读取出来赋值给一个字符串变量,然后删除StreamingAssets文件夹和里面的文件

如果文件只是读取,例如加载资源,直接用Application.streamingAssetsPath。
如果保存下载的文件,mac和windows用Application.streamingAssetsPath,ios和android用Application.persistentDataPath
如果是热更新替换资源,对于移动端需要先把文件放在Application.streamingAssetsPath,然后拷贝到Application.persistentDataPath进行资源替换。

在移动端为什么用Application.streamingAssetsPath目录而不能用Application.dataPath加自定义目录?
进过实际验证
iOS移动端StreamingAssets文件夹电脑端提前创建后,可读到。Assets目录提前在电脑创建的文件夹,移动端Application.dataPath加文件夹名读取不到。
iOS移动端StreamingAssets和Assets目录下文件夹不能代码动态创建。
结论:iOS移动端只读资源可以用Application.streamingAssetsPath(StreamingAssets文件夹在电脑端提前创建好),可读可写需求移动端需要使用Application.persistentDataPath目录。

using System.Collections;
using System.Collections.Generic;
using System.IO;
using UnityEngine;
using UnityEngine.Networking;


//如果文件只是读取,例如加载资源,直接用Application.streamingAssetsPath。
//如果保存下载的文件,mac和windows用Application.streamingAssetsPath,ios和android用Application.persistentDataPath
//如果是热更新替换资源,对于移动端需要先把文件放在Application.streamingAssetsPath,然后拷贝到Application.persistentDataPath进行资源替换。

// 在移动端为什么用Application.streamingAssetsPath目录而不能用Application.dataPath加自定义目录?
// 进过实际验证
// iOS移动端StreamingAssets文件夹电脑端提前创建后,可读到。Assets目录提前在电脑创建的文件夹,移动端Application.dataPath加文件夹名读取不到。
// iOS移动端StreamingAssets和Assets目录下文件夹不能代码动态创建。
// 结论:iOS移动端只读资源可以用Application.streamingAssetsPath(StreamingAssets文件夹在电脑端提前创建好),可读可写需求移动端需要使用Application.persistentDataPath目录。

//创建文件夹StreamingAssets,将字符123/n456/n789/n写入文件test.txt。然后把文件转换为byte数组发给服务端。再把文件里的数据读取出来赋值给一个字符串变量,然后删除StreamingAssets文件夹和里面的文件


public class Demo : MonoBehaviour
{
    string inputStr = "123/n456/n789/n";
    string outputStr = "";
    string outputStr2 = "";

    byte[] byteData = new byte[2] { 0, 0 };
    byte[] byteData2 = new byte[2] { 0, 0 };

    void Start()
    {

        WriteFile(inputStr, StreamingAssetsPath() + "/test.txt");
        outputStr = ReadFile(StreamingAssetsPath() + "/test.txt");
        Debug.Log($"outputStr = {outputStr}");
        StartCoroutine(UploadFileRequest(StreamingAssetsPath() + "/test.txt", "https://tttv.qiaohuapp.com/api/v2.0/games/upload"));
        //删除
        //DeleteDirectoryAndAllFiles(StreamingAssetsPath());

        CreateDirectory(DataPath() + "/dr");
        //这一句可以写入前创建出test.txt文件
        WriteFile(inputStr, DataPath() + "/dr" + "/test.txt");
        outputStr = ReadFile(DataPath() + "/dr" + "/test.txt");
        Debug.Log($"outputStr = {outputStr}");
        StartCoroutine(UploadFileRequest(DataPath() + "/dr" + "/test.txt", "https://tttv.qiaohuapp.com/api/v2.0/games/upload"));
        //删除
        DeleteDirectoryAndAllFiles(DataPath() + "/dr");

        byteData[1] = 1;
        //这一句可以写入前创建出test2.txt文件
        ChangeByteToFile(DataPath() + "/dr" + "/test2.txt", byteData, byteData.Length);
        byteData2 = ChangeFileToByte(DataPath() + "/dr" + "/test2.txt");

        foreach (var item in byteData2)
        {
            Debug.Log($"byteData2 item = {item}");
        }



    }

    public string DataPath()
    {
        //对应文件夹Assets
        return Application.dataPath;
    }

    //提前手动创建treamingAssets文件夹后,再操作时的路径
    public string StreamingAssetsPath()
    {
        //对应文件夹Assets/StreamingAssets
        //mac和windows端是可读可写,ios和android端是只读
        string path = "";

        if (Application.platform == RuntimePlatform.WindowsEditor || Application.platform == RuntimePlatform.OSXEditor || Application.platform == RuntimePlatform.IPhonePlayer)
        {
            path = "file://" + Application.streamingAssetsPath;
            Debug.Log("StreamingAssetsPath WindowsEditor OR OSXEditor OR iOS  = " + path);
        }
        else if (Application.platform == RuntimePlatform.Android)
        {
            path = Application.streamingAssetsPath;
            Debug.Log("StreamingAssetsPath Android= " + path);
        }

        return path;
    }

    public string PersistentDataPath()
    {
        //移动端是可读可写,persistentDataPath文件夹是apk安装以后,才形成的一个文件夹,无法提前创建。
        //下载的文件和把streamingAssetsPath文件拷贝进来后可以读写操作。
        return Application.persistentDataPath;
    }

    //加载资源路径
    public string LoadResourcesPath()
    {
        return StreamingAssetsPath();
    }

    //下载路径
    public string DownLoadPath()
    {
        if (Application.platform == RuntimePlatform.IPhonePlayer || Application.platform == RuntimePlatform.Android)
        {
            return Application.persistentDataPath;
        }
        else if (Application.platform == RuntimePlatform.OSXEditor || Application.platform == RuntimePlatform.WindowsEditor)
        {
            return Application.streamingAssetsPath;
        }

        return "";
    }

    public bool IsDirectoryExist(string directoryName)
    {
        return Directory.Exists(directoryName);
    }

    public void CreateDirectory(string directoryName)
    {
    	if(!Directory.Exists(directoryName))
    	{
    		Directory.CreateDirectory(directoryName);
    	}
        
    }
    //删除文件夹前,需要先把里面的文件删除,不然会报错
    public void DeleteDirectory(string directoryName)
    {
        Directory.Delete(directoryName);
    }
    /// <summary>
    /// 可以一次性删掉文件夹和里面的所有文件
    /// </summary>
    /// <param name="directoryName"></param>
    public void DeleteDirectoryAndAllFiles(string directoryName)
    {
        DirectoryInfo di = new DirectoryInfo(directoryName);
        di.Delete(true);
    }

    public void MoveDirectory(string sourcePath, string targetPath)
    {
        Directory.Move(sourcePath, targetPath);
    }


    public bool IsFileExist(string fileName)
    {
        return File.Exists(fileName);
    }

    public void CreateFile(string fileName)
    {
        if(!File.Exists(fileName))
        {
            File.Create(fileName);
        }
        
    }

    public void DeleteFile(string fileName)
    {
        File.Delete(fileName);
    }

    public void MoveFile(string sourcePath, string targetPath)
    {
        File.Move(sourcePath, targetPath);
    }

    public void WriteFile(string str, string fileName)
    {
        try
        {
            StreamWriter sw = new StreamWriter(fileName);
            sw.Write(str);
            sw.Close();
        }
        catch (System.Exception ex)
        {
            Debug.Log($"error = {ex}");
        }

    }

    public string ReadFile(string fileName)
    {
        string str = "";
        try
        {
            StreamReader sr = new StreamReader(fileName);
            //如果内容为空,返回为-1
            if (sr.Peek() != -1)
            {
                str = sr.ReadToEnd();
                sr.Close();
            }
        }
        catch (System.Exception ex)
        {
            Debug.Log($"error = {ex}");
        }
        return str;
    }


    //接收到byte数组数据,转换为文件(例如txt文件,mp3文件,jpg文件)
    public void ChangeByteToFile(string fileName, byte[] bytes, int length)
    {
        FileStream fs = new FileStream(fileName, FileMode.OpenOrCreate);
        fs.Write(bytes, 0, length);
        fs.Close();
    }

    //把文件(例如txt文件,mp3文件,jpg文件)转为byte数组数据,发送给服务端
    public byte[] ChangeFileToByte(string fileName)
    {
        FileStream fs = new FileStream(fileName, FileMode.Open);
        //获取FileStream的长度,开辟对应的byte内存空间
        byte[] data = new byte[fs.Length];
        //因为data是数组,数组是引用类型,这里data作为参数,fs.Read运行后,外层的data也能获取到对应数据,所以这里可以return data数据
        fs.Read(data, 0, data.Length);
        fs.Close();
        return data;
    }

    /// <summary>
    /// 将文件发送给服务端(字节流形式)
    /// </summary>
    /// <param name="filePath"></param>
    /// <param name="url"></param>
    /// <returns></returns>
    public IEnumerator UploadFileRequest(string filePath, string url)
    {
        WWWForm form = new WWWForm();
        form.AddBinaryData("file", ChangeFileToByte(filePath));
        string token = "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIyMTMxNTk1NSIsInFpYW9odU5ld1VzZXIiOjAsInVzZXJfbmFtZSI6IjE4MjE4MjQyMzM3IiwibW9iaWxlIjoiMTgyMTgyNDIzMzciLCJoYXNSaWdodCI6MCwidmVyc2lvbiI6IiIsImF1dGhvcml0aWVzIjpbIk4vQSJdLCJjbGllbnRfaWQiOiJxaC10ZXNsYS1hcHAiLCJhdWQiOlsicWgtZWluc3RlaW4tcmVzdCIsInFoLXF1ZXRlbGV0LXJlc3RkYXRhIiwicWgtdGVzbGEtcmVzdCJdLCJzY29wZSI6WyJ0cnVzdCJdLCJuaWNrbmFtZSI6IueUqOaItzAzM0RDRjAiLCJhdXRob3JTdGF0dXMiOiIwIiwiZXhwIjoxNjU0MTM3NzYxLCJ1Y29kZSI6IjE2OTQxNzA2MDIiLCJqdGkiOiJhNzJmY2Y5Mi01NzUwLTQyMzktYjVlMi02Y2ViYzk0YjM4NTQifQ.P5STi7KuE78sjpDRIIIjDtmZ8sdv54yHRNDn0Dbmh0g";
        UnityWebRequest uwr = UnityWebRequest.Post(url, form);
        uwr.SetRequestHeader("Authorization", token);
        yield return uwr.SendWebRequest();
        if (uwr.isNetworkError || uwr.isHttpError)
        {
            Debug.LogError("文件上传失败 = " + uwr.error);
        }
        else
        {
            Debug.Log("文件上传成功,结果 = " + uwr.downloadHandler.text);
        }
    }



}