Unity AssetBundle打包

using UnityEngine;
using UnityEditor;
using System.IO;

/// <summary>  
/// 把其他目录下的资源打包成.unity3d 到StreamingAssets目录下  
/// </summary>  
public class BuildAssetBundle : Editor
{
    public static string m_SourcePath = Application.dataPath + "/BundleRes";
    private static string m_AssetbundlesOutPutPath = Application.streamingAssetsPath;
    [MenuItem("AssetBundle/BuildAssetBundle")]
    public static void BuildAssetBundles()
    {
        ClearAssetbundlesName();
        Pack(m_SourcePath);
        string outputPath = Path.Combine(m_AssetbundlesOutPutPath,Platform.GetPlatformFolder(EditorUserBuildSettings.activeBuildTarget));
        Debug.Log("outputPath: "+ outputPath);
        if(!Directory.Exists(outputPath))
        {
            Directory.CreateDirectory(outputPath);
        }
        //根据BuildSetting里面所**的平台进行打包
        //BuildAssetBundleOptions
        //BuildAssetBundleOptions.None：使用LZMA算法压缩，压缩的包更小，但是加载时间更长。
        //使用之前需要整体解压。一旦被解压，这个包会使用LZ4重新压缩。使用资源的时候不需要整体解压。
        //在下载的时候可以使用LZMA算法，一旦它被下载了之后，它会使用LZ4算法保存到本地上。
        //BuildAssetBundleOptions.UncompressedAssetBundle：不压缩，包大，加载快
        //BuildAssetBundleOptions.ChunkBasedCompression：使用LZ4压缩，压缩率没有LZMA高，
        //但是我们可以加载指定资源而不用解压全部。
        //注意: 使用LZ4压缩，可以获得可以跟不压缩想媲美的加载速度，而且比不压缩文件要小。
        BuildPipeline.BuildAssetBundles(outputPath,BuildAssetBundleOptions.None,EditorUserBuildSettings.activeBuildTarget);
        AssetDatabase.Refresh();
        Debug.Log("打包完成 !!!");
    }

    /// <summary>
    /// 清除之前设置的AssetbundleName 避免不必要的资源也会进行打包 
    /// 只要设置了AssetbundleName的不论在什么目录都会被打包
    /// </summary>
    public static void ClearAssetbundlesName()
    {
        //string[] oldAssetbundleNames = AssetDatabase.GetAllAssetBundleNames();
        //获取所有的AssetbunldeName总个数
        int length = AssetDatabase.GetAllAssetBundleNames().Length;
        Debug.Log("清除之前的BunldeNameLength:  " + length);
        string[] oldAssetbundleNames = new string[length];
        for (int i = 0; i < length; i++)
        {
            //获取AssetbundleName
            oldAssetbundleNames[i] = AssetDatabase.GetAllAssetBundleNames()[i];
        }
        for (int i = 0; i < oldAssetbundleNames.Length; i++)
        {
            //移除AssetBunldeName
            AssetDatabase.RemoveAssetBundleName(oldAssetbundleNames[i],true);
        }
        length = AssetDatabase.GetAllAssetBundleNames().Length;
        Debug.Log("清除之后的BunldeNameLength:  "+length);
    }

    /// <summary>
    /// 获取指定路径下所有文件
    /// </summary>
    /// <param name="source"></param>
    public static void Pack(string source)
    {
        //获取该路径下的文件信息
        DirectoryInfo folder = new DirectoryInfo(source);
        FileSystemInfo[] files = folder.GetFileSystemInfos();
        int length = files.Length;
        for (int i = 0; i < length; i++)
        {
            if(files[i] is DirectoryInfo)//如果是文件夹就继续调用
            {
                Pack(files[i].FullName);
            }
            else
            {
                //如果不是meta文件
                if (!files[i].Name.EndsWith(".meta")) 
                {
                    file(files[i].FullName);
                }
            }
        }
    }

    /// <summary>
    /// 设置AssetbundleName
    /// </summary>
    /// <param name="source"></param>
    public static void file(string source)
    {
        string _source = Replace(source);
        string _assetPath1 = "Assets" + _source.Substring(Application.dataPath.Length);
        string _assetPath2 = _source.Substring(Application.dataPath.Length + 1);
        AssetImporter assetImporter = AssetImporter.GetAtPath(_assetPath1);
        string assetName = _assetPath2.Substring(_assetPath2.IndexOf("/") + 1);
        Debug.Log("source: " + source + " _assetPath1:  " + _assetPath1 + "  _assetPath2:  " + _assetPath2+ "  assetName: "+ assetName+ "  Path.GetExtension(assetName): "+ Path.GetExtension(assetName));
        //Path.GetExtension(assetName) 获取扩展名
        assetName = assetName.Replace(Path.GetExtension(assetName),".unity3d");
        assetImporter.assetBundleName = assetName;
    }

    public static string Replace(string str)
    {
        return str.Replace(@"\\","/");
    }
}

public class Platform
{
    public static string GetPlatformFolder(BuildTarget target)
    {
        switch (target)
        {
            case BuildTarget.Android:
                return "Android";
            case BuildTarget.iOS:
                return "IOS";
            //case BuildTarget.WebPlayer:
            //    return "WebPlayer";
            case BuildTarget.StandaloneWindows:
            case BuildTarget.StandaloneWindows64:
                return "Windows";
            case BuildTarget.StandaloneOSXIntel:
            case BuildTarget.StandaloneOSXIntel64:
            //case BuildTarget.StandaloneOSXUniversal:
                return "OSX";
            default:
                return null;
        }
    }
}