Struts2中文件下载

在struts.xml中配置如下

        <action name="download" class="cn.itcast.domain.User" method="download">
            <result type="stream" name="success">
                <param name="contentType">application/octet-stream</param>
                <param name="inputStream">inputStream</param><!-- 输入是对应的动作类中的那个字段 -->
                <param name="contentDisposition">attachment;filename=${filename}</param><!-- 要下载的文件名 -->
            </result>

jsp页面中

user为action中传来的

          <c:url value="/user/download" var="url">
              <c:param name="path" value="${user.path}"></c:param>
              <c:param name="filename" value="${user.filename}"></c:param>
          </c:url>
          <a href="${url}">下载</a>

在User.java中

class User{
    private String path;        //文件保存的路径
    private String filename;    //文件名
//文件下载  固定名字
    private InputStream inputStream;
    public InputStream getInputStream() {
        return inputStream;
    }
    public void setInputStream(InputStream inputStream) {
        this.inputStream = inputStream;
    }

    public String download()
    {
        String storePath=ServletActionContext.getServletContext().getRealPath("/files");
        System.out.println("before" +path +"   "+ filename);
　　　　　　　　//事实证明struts2中处理了相关参数, 并且通过url传输传给 path, filename中的值
//        path=ServletActionContext.getRequest().getParameter("path");
//        filename=ServletActionContext.getRequest().getParameter("filename");
        System.out.println("after" +path +"   "+ filename);
        try {
            inputStream=new FileInputStream(storePath+"\"+path+"\"+filename);
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return this.SUCCESS;
    }
}