unity加载下载播放MP3

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

public class Downdload : MonoBehaviour
{
public AudioSource audioSource;
string urlPath;//资源网络路径
string file_SaveUrl;//资源保路径
FileInfo file;
public static Downdload instance;
private bool p = true;
private bool down;
private float t;
private float time;
private void Awake()
{
instance = this;
}
private void Start()
{
time = 3;
t = 0;
}
public void play()
{
urlPath = @"<span style="font-family: "Microsoft YaHei"; font-size: 14px; line-height: 21px;">http://m128.xiami.net/712/55712/2100253402/1775451414_59502672_l.mp3?auth_key=1508986800-0-0-eaddaaacb20bc6f1fe4dc8ee89ba0732</span>"<span style="font-family:Microsoft YaHei;"><span style="font-size: 14px;">;</span></span>
file_SaveUrl = @"D:\Music\123.mp3";//保存的本地路径 记得加上文件后缀名
file = new FileInfo(file_SaveUrl);
Debug.Log(file_SaveUrl);
DirectoryInfo mydir = new DirectoryInfo(file_SaveUrl);
if (File.Exists(file_SaveUrl))//判断一下本地是否有了该音频 如果有就不需下载
{
string s = @"file://" + file_SaveUrl;
StartCoroutine(LoadAudio(s));
}
else
{
StartCoroutine(DownFile(urlPath));
}
}
IEnumerator DownFile(string url)
{

    WWW www = new WWW(url);  
    down = false;  
    yield return www;  
    down = true;  
    if (www.isDone)  
    {  
        Debug.Log("下载完成");  
        byte[] bytes = www.bytes;  
        CreatFile(bytes);  
        string str = @"file://" + file_SaveUrl;  
        StartCoroutine(LoadAudio(str));  
    }  
}  
void CreatFile(byte[] bytes)  
{  
    Stream stream;  
    stream = file.Create();  
    stream.Write(bytes, 0, bytes.Length);  
    stream.Close();  
    stream.Dispose();  
}  
public IEnumerator LoadAudio(string recordPath)  
{  
    WWW www = new WWW(recordPath);  
    yield return www;  
    AudioClip ac = WWWAudioExtensions.GetAudioClip(www);  
    if (www.isDone)  
    {  
        audioSource.clip = ac;  
        audioSource.Play();  
    }  
}  

}