diff --git a/models/file.go b/models/file.go
index b23842d..098baeb 100644
--- a/models/file.go
+++ b/models/file.go
@@ -17,6 +17,9 @@ type File struct {
 	FolderID   uint `gorm:"index:folder_id"`
 	PolicyID   uint
 	Dir        string `gorm:"size:65536"`
+
+	// 关联模型
+	Policy Policy `gorm:"PRELOAD:false,association_autoupdate:false"`
 }
 
 // Create 创建文件记录
@@ -41,3 +44,12 @@ func (folder *Folder) GetChildFile() ([]File, error) {
 	result := DB.Where("folder_id = ?", folder.ID).Find(&files)
 	return files, result.Error
 }
+
+// GetPolicy 获取文件所属策略
+// TODO:test
+func (file *File) GetPolicy() *Policy {
+	if file.Policy.Model.ID == 0 {
+		file.Policy, _ = GetPolicyByID(file.PolicyID)
+	}
+	return &file.Policy
+}
diff --git a/pkg/filesystem/context.go b/pkg/filesystem/context.go
index 3c7406f..adce850 100644
--- a/pkg/filesystem/context.go
+++ b/pkg/filesystem/context.go
@@ -9,4 +9,6 @@ const (
 	SavePathCtx
 	// FileHeaderCtx 上传的文件
 	FileHeaderCtx
+	// PathCtx 文件或目录的虚拟路径
+	PathCtx
 )
diff --git a/pkg/filesystem/errors.go b/pkg/filesystem/errors.go
index c824b50..98aa8c8 100644
--- a/pkg/filesystem/errors.go
+++ b/pkg/filesystem/errors.go
@@ -1,6 +1,9 @@
 package filesystem
 
-import "errors"
+import (
+	"errors"
+	"github.com/HFO4/cloudreve/pkg/serializer"
+)
 
 var (
 	ErrUnknownPolicyType       = errors.New("未知存储策略类型")
@@ -8,7 +11,8 @@ var (
 	ErrFileExtensionNotAllowed = errors.New("不允许上传此类型的文件")
 	ErrInsufficientCapacity    = errors.New("容量空间不足")
 	ErrIllegalObjectName       = errors.New("目标名称非法")
-	ErrInsertFileRecord        = errors.New("无法插入文件记录")
+	ErrInsertFileRecord        = serializer.NewError(serializer.CodeDBError, "无法插入文件记录", nil)
 	ErrFileExisted             = errors.New("同名文件已存在")
-	ErrPathNotExist            = errors.New("路径不存在")
+	ErrPathNotExist            = serializer.NewError(404, "路径不存在", nil)
+	ErrObjectNotExist          = serializer.NewError(404, "文件不存在", nil)
 )
diff --git a/pkg/filesystem/file.go b/pkg/filesystem/file.go
index d9ae304..99943cd 100644
--- a/pkg/filesystem/file.go
+++ b/pkg/filesystem/file.go
@@ -5,6 +5,7 @@ import (
 	"errors"
 	model "github.com/HFO4/cloudreve/models"
 	"github.com/HFO4/cloudreve/pkg/serializer"
+	"github.com/HFO4/cloudreve/pkg/util"
 	"io"
 )
 
@@ -36,7 +37,28 @@ func (fs *FileSystem) AddFile(ctx context.Context, parent *model.Folder) (*model
 	return &newFile, nil
 }
 
-// Download 处理下载文件请求
+// Download 处理下载文件请求，path为虚拟路径
+// TODO:测试
 func (fs *FileSystem) Download(ctx context.Context, path string) (io.ReadCloser, error) {
+	// 触发`下载前`钩子
+	err := fs.Trigger(ctx, fs.BeforeFileDownload)
+	if err != nil {
+		util.Log().Debug("BeforeFileDownload 钩子执行失败，%s", err)
+		return nil, err
+	}
+
+	// 找到文件
+	exist, file := fs.IsFileExist(path)
+	if !exist {
+		return nil, ErrObjectNotExist
+	}
+
+	// 将当前存储策略重设为文件使用的
+	fs.Policy = file.GetPolicy()
+	err = fs.dispatchHandler()
+	if err != nil {
+		return nil, err
+	}
+
 	return nil, serializer.NewError(serializer.CodeEncryptError, "人都的", errors.New("不是人都的"))
 }
diff --git a/pkg/filesystem/filesystem.go b/pkg/filesystem/filesystem.go
index 511598a..bec6f50 100644
--- a/pkg/filesystem/filesystem.go
+++ b/pkg/filesystem/filesystem.go
@@ -29,10 +29,10 @@ type Handler interface {
 
 // FileSystem 管理文件的文件系统
 type FileSystem struct {
-	/*
-	   文件系统所有者
-	*/
+	// 文件系统所有者
 	User *model.User
+	// 操作文件使用的上传策略
+	Policy *model.Policy
 
 	/*
 	   钩子函数
@@ -45,6 +45,8 @@ type FileSystem struct {
 	AfterValidateFailed []Hook
 	// 用户取消上传后
 	AfterUploadCanceled []Hook
+	// 文件下载前
+	BeforeFileDownload []Hook
 
 	/*
 	   文件系统处理适配器
@@ -54,21 +56,36 @@ type FileSystem struct {
 
 // NewFileSystem 初始化一个文件系统
 func NewFileSystem(user *model.User) (*FileSystem, error) {
-	var handler Handler
-
-	// 根据存储策略类型分配适配器
-	switch user.Policy.Type {
-	case "local":
-		handler = local.Handler{}
-	default:
-		return nil, ErrUnknownPolicyType
+	fs := &FileSystem{
+		User: user,
 	}
 
+	// 分配存储策略适配器
+	err := fs.dispatchHandler()
+
 	// TODO 分配默认钩子
-	return &FileSystem{
-		User:    user,
-		Handler: handler,
-	}, nil
+	return fs, err
+}
+
+// dispatchHandler 根据存储策略分配文件适配器
+// TODO: 测试
+func (fs *FileSystem) dispatchHandler() error {
+	var policyType string
+	if fs.Policy == nil {
+		// 如果没有具体指定，就是用用户当前存储策略
+		policyType = fs.User.Policy.Type
+	} else {
+		policyType = fs.Policy.Type
+	}
+
+	// 根据存储策略类型分配适配器
+	switch policyType {
+	case "local":
+		fs.Handler = local.Handler{}
+		return nil
+	default:
+		return ErrUnknownPolicyType
+	}
 }
 
 // NewFileSystemFromContext 从gin.Context创建文件系统
diff --git a/pkg/filesystem/hooks.go b/pkg/filesystem/hooks.go
index fd89db6..558ac04 100644
--- a/pkg/filesystem/hooks.go
+++ b/pkg/filesystem/hooks.go
@@ -21,6 +21,8 @@ func (fs *FileSystem) Use(name string, hook Hook) {
 		fs.AfterValidateFailed = append(fs.AfterValidateFailed, hook)
 	case "AfterUploadCanceled":
 		fs.AfterUploadCanceled = append(fs.AfterUploadCanceled, hook)
+	case "BeforeFileDownload":
+		fs.BeforeFileDownload = append(fs.BeforeFileDownload, hook)
 	}
 }
 
@@ -37,6 +39,15 @@ func (fs *FileSystem) Trigger(ctx context.Context, hooks []Hook) error {
 	return nil
 }
 
+// HookIsFileExist 检查虚拟路径文件是否存在
+func HookIsFileExist(ctx context.Context, fs *FileSystem) error {
+	filePath := ctx.Value(PathCtx).(string)
+	if ok, _ := fs.IsFileExist(filePath); ok {
+		return nil
+	}
+	return ErrObjectNotExist
+}
+
 // HookValidateFile 一系列对文件检验的集合
 func HookValidateFile(ctx context.Context, fs *FileSystem) error {
 	file := ctx.Value(FileHeaderCtx).(FileHeader)
@@ -107,10 +118,10 @@ func GenericAfterUpload(ctx context.Context, fs *FileSystem) error {
 	}
 
 	// 检查文件是否存在
-	if fs.IsFileExist(path.Join(
+	if ok, _ := fs.IsFileExist(path.Join(
 		virtualPath,
 		ctx.Value(FileHeaderCtx).(FileHeader).GetFileName(),
-	)) {
+	)); ok {
 		return ErrFileExisted
 	}
 
diff --git a/pkg/filesystem/path.go b/pkg/filesystem/path.go
index 0e9cdfb..a06b7fe 100644
--- a/pkg/filesystem/path.go
+++ b/pkg/filesystem/path.go
@@ -108,7 +108,7 @@ func (fs *FileSystem) CreateDirectory(ctx context.Context, fullPath string) erro
 	}
 
 	// 是否有同名文件
-	if fs.IsFileExist(path.Join(base, dir)) {
+	if ok, _ := fs.IsFileExist(path.Join(base, dir)); ok {
 		return ErrFileExisted
 	}
 
@@ -133,11 +133,11 @@ func (fs *FileSystem) IsPathExist(path string) (bool, *model.Folder) {
 }
 
 // IsFileExist 返回给定路径的文件是否存在
-func (fs *FileSystem) IsFileExist(fullPath string) bool {
+func (fs *FileSystem) IsFileExist(fullPath string) (bool, model.File) {
 	basePath := path.Dir(fullPath)
 	fileName := path.Base(fullPath)
 
-	_, err := model.GetFileByPathAndName(basePath, fileName, fs.User.ID)
+	file, err := model.GetFileByPathAndName(basePath, fileName, fs.User.ID)
 
-	return err == nil
+	return err == nil, file
 }
diff --git a/pkg/filesystem/path_test.go b/pkg/filesystem/path_test.go
index 58aa521..718de10 100644
--- a/pkg/filesystem/path_test.go
+++ b/pkg/filesystem/path_test.go
@@ -21,7 +21,7 @@ func TestFileSystem_IsFileExist(t *testing.T) {
 	mock.ExpectQuery("SELECT(.+)").WithArgs(uint(1), "/s", "1.txt").WillReturnRows(
 		sqlmock.NewRows([]string{"Name"}).AddRow("s"),
 	)
-	testResult := fs.IsFileExist("/s/1.txt")
+	testResult, _ := fs.IsFileExist("/s/1.txt")
 	asserts.True(testResult)
 	asserts.NoError(mock.ExpectationsWereMet())
 
@@ -29,7 +29,7 @@ func TestFileSystem_IsFileExist(t *testing.T) {
 	mock.ExpectQuery("SELECT(.+)").WithArgs(uint(1), "/ss/dfsd", "1.txt").WillReturnRows(
 		sqlmock.NewRows([]string{"Name"}),
 	)
-	testResult = fs.IsFileExist("/ss/dfsd/1.txt")
+	testResult, _ = fs.IsFileExist("/ss/dfsd/1.txt")
 	asserts.False(testResult)
 	asserts.NoError(mock.ExpectationsWereMet())
 }
diff --git a/pkg/filesystem/upload.go b/pkg/filesystem/upload.go
index 2887ea3..d658527 100644
--- a/pkg/filesystem/upload.go
+++ b/pkg/filesystem/upload.go
@@ -44,7 +44,7 @@ func (fs *FileSystem) Upload(ctx context.Context, file FileHeader) (err error) {
 		followUpErr := fs.Trigger(ctx, fs.AfterValidateFailed)
 		// 失败后再失败...
 		if followUpErr != nil {
-			util.Log().Warning("AfterValidateFailed 钩子执行失败，%s", followUpErr)
+			util.Log().Debug("AfterValidateFailed 钩子执行失败，%s", followUpErr)
 		}
 
 		return err
@@ -85,7 +85,7 @@ func (fs *FileSystem) CancelUpload(ctx context.Context, path string, file FileHe
 		ctx = context.WithValue(ctx, SavePathCtx, path)
 		err := fs.Trigger(ctx, fs.AfterUploadCanceled)
 		if err != nil {
-			util.Log().Warning("执行 AfterUploadCanceled 钩子出错，%s", err)
+			util.Log().Debug("执行 AfterUploadCanceled 钩子出错，%s", err)
 		}
 	}
 }
diff --git a/service/explorer/file.go b/service/explorer/file.go
index 1d1b0c5..00079c8 100644
--- a/service/explorer/file.go
+++ b/service/explorer/file.go
@@ -18,9 +18,10 @@ func (service *FileDownloadService) Download(ctx context.Context, c *gin.Context
 	fs, err := filesystem.NewFileSystemFromContext(c)
 	if err != nil {
 		return serializer.Err(serializer.CodePolicyNotAllowed, err.Error(), err)
-
 	}
 
+	// 开始处理下载
+	ctx = context.WithValue(ctx, filesystem.GinCtx, c)
 	_, err = fs.Download(ctx, service.Path)
 
 	if err != nil {