UnityWebRequest(WWW——已过时)
替代：Unity不再支持WWW后，使用UnityWebRequest完成web请求。
Unity - Scripting API: UnityWebRequest (unity3d.com)
https://docs.unity3d.com/ScriptReference/Networking.UnityWebRequest.html
if (www.isNetworkError || www.isHttpError——已过时
替代：if(www.result == UnityWebRequest.Result.ConnectionError)
请求本地权限问题（疑是文件权限问题，未解决）：
UnauthorizedAccessException:
Access to the path 'E:\Unity\Proj\xxx\xxx\h\to\file' is denied.
代码如下：
public class VideoDownloader : MonoBehaviour
{public string json;void Start(){// 协程// public Coroutine StartCoroutine(IEnumerator routine);StartCoroutine(DownloadVideo());}IEnumerator DownloadVideo(){// 使用UnityWebRequestUnityWebRequest www = UnityWebRequest.Get("http://localhost:9090/Video/unity_xmScene.mp4");yield return www.SendWebRequest();//if (www.isNetworkError || www.isHttpError) // 已过时——2023年测Debug.Log(UnityWebRequest.Result.ConnectionError); // 返回值——ConnectionErrorif (www.result == UnityWebRequest.Result.ConnectionError){Debug.Log(www.error);}else{Debug.Log("保存资源到本地！");// Show results as textDebug.Log(www.downloadHandler.text);// Or retrieve results as binary databyte[] results = www.downloadHandler.data;Debug.Log(results);//SaveJsonData("test2.txt");// 写字节——public static void WriteAllBytes(string path, byte[] bytes);// File.WriteAllBytes("path/to/file/", www.downloadHandler.data);File.WriteAllBytes("path/to/file/test.txt", www.downloadHandler.data);}/*// 使用过时WWW，WWW.bytes保存资源文件var www = new WWW("http://localhost:9090/Video/unity_xmScene.mp4");File.WriteAllBytes("path/to/file", www.bytes);*/}
