Struts2 action返回图片流 (转载的)

struts.xml代码：

<action name="getDocumentImgByFileId" class="checkInfoAction" method="getDocumentImgByFileId">
<result type="stream" name="SUCCESS">
<param name="contentType">image/jpeg</param>
<param name="inputName">inputStream</param>
</result>
</action>

action类代码：

/**
 * 获取图片流
 * @return
 */
public String getDocumentImg() {
    model = (JcOffDocument)baseBO.load(model);
    String imgUrl = getAllPath(model);
    //String imgUrl = "/jczfoa/images/aa.jpg";

    if(!MyUtils.isFileExist(imgUrl, "")){//如果指定的图片不存在，显示默认图片
        imgUrl = getSession().getServletContext().getRealPath("/")+"images"+File.separator+"zw.jpg";
    }

    try {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        InputStream input = new BufferedInputStream(new FileInputStream(imgUrl));
        byte[] bt = new byte[1024];
        while (input.read(bt) > 0) {
            bos.write(bt);
        }
        this.inputStream = new ByteArrayInputStream(bos.toByteArray());
        bos.close();
        input.close();
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return SUCCESS;
}
private ByteArrayInputStream inputStream;

public ByteArrayInputStream getInputStream() {
    return inputStream;
}
public void setInputStream(ByteArrayInputStream inputStream) {
    this.inputStream = inputStream;
}