实现动态文件内容的下载

web.xml文件中定义  
<servlet>
    <description>This is the description of my J2EE component</description>
    <display-name>This is the display name of my J2EE component</display-name>
    <servlet-name>Attachment</servlet-name>
    <servlet-class>Attachment</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>Attachment</servlet-name>
    <url-pattern>/servlet/Attachment</url-pattern>
  </servlet-mapping>
java 文件。
public class Attachment extends HttpServlet {

private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("application/x-msdownload()");
response.addHeader("Content-Disposition", "attachment;filename=test.txt");
ServletOutputStream sos = response.getOutputStream();
sos.write("测试一".getBytes());
sos.write("sdfksdjfkljsdklfjlskdjflksd".getBytes());
sos.close();

}

}
jsp中引用：
<a href="servlet/Attachment">下载附件</a>