前些天，写了一段代码，struts2下载的，但是无论我怎么改都不能弹出保存的对话框，在此向各位大神们求助了。代码如下

 private String fileName; 
 private ServletContext context; 
 private InputStream inStream;
 private String mimeType;
public String getFileName(){
    try {
        return new String(fileName.getBytes(), "ISO8859-1");
    } catch (UnsupportedEncodingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
        return this.fileName;
    }
}
public void setFileName(String fileName) {
    try {
        this.fileName = new String(fileName.getBytes("ISO-8859-1"),"UTF-8");
    } catch (UnsupportedEncodingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

public String download(){
     mimeType = context.getMimeType(fileName);
    return "success";
}


public InputStream getDownloadFile() throws UnsupportedEncodingException
{

    String path = "/file/";
    // 取得目录文件流返回。
    inStream =  context.getResourceAsStream(path+fileName);
    return inStream;    
}

public void setServletContext(ServletContext context) {
     this.context = context;
}

 public String getMimeType() {  
        return mimeType;  
    }

Struts的配置是：



downloadFile
${mimeType}
attachment;filename="${fileName}"
100000

出现的情况为：

Content-Disposition:为空，什么都没有？