关于通过Action取文件图片

有一个Object  存放文件（图片）

public class AttachmentFile {

      private String url; //文件路径

//...

}

另一个Object包含AttachmentFile

public class Sight {

    private AttachmentFile sightPic;
//...

}

我的目的是要在视图中显示此Sight对应AttachmentFile中的图片，那么应该如下操作。

Action：

public class SightAction extends BaseFileAction{

private Sight sight;

public String viewImage() throws Exception {
        java.BaseFileAction.outPutImageStream(sight.getSightPic().getUrl());
        return SUCCESS;
   }

}

public class BaseFileAction extends BaseAction {

public FileInputStream inputStream;    

protected void outPutImageStream(String imagePath) throws FileNotFoundException {

File file = new File(imagePath);

inputStream = new FileInputStream(file);

    }

//...

}

在XML中应这样配置

<action name="viewSightImage"  class="..action.SightAction" method="viewImage">
            <result name="success" type="stream">
                <param name="contentType">online</param>
            </result>
</action>

在视图中直接按如下显示就可以了

 <img src="viewSightImage.action?sight.sightPic.url=${sightPic.url}"/>