Servlet与JSP的通信

以下的代码片段演示了一个servlet，它例示(instantiates)一个bean并且用由浏览器发送的Form数据将它初始化。此后bean被加入request,而这一要求被送到JSP页面（Bean1.jsp）,JSP通过request取得并做进一步处理。

public void doPost (HttpServletRequest request,
HttpServletResponse response) {

try {
govi.FormBean f = new govi.FormBean();
String id = request.getParameter("id");
f.setName(request.getParameter("name"));
f.setAddr(request.getParameter("addr"));
f.setAge(request.getParameter("age"));
//use the id to compute
//additional bean properties like info
//maybe perform a db query, etc.
// . . .
f.setPersonalizationInfo(info);
request.setAttribute("fBean",f);
getServletConfig().getServletContext().getRequestDispatcher
("/jsp/Bean1.jsp").forward(request, response);
} catch (Exception ex) {
. . .
}
}

在将它从通过useBean操作中的缺省的请求范围，即scope首次执行后，即可在JSP文件的Bean1.jsp处理fBean。

<jsp:useBean id="fBean" class="govi.FormBean" scope="request"/>
<jsp:getProperty name="fBean" property="name" />
<jsp:getProperty name="fBean" property="addr" />
<jsp:getProperty name="fBean" property="age" />
<jsp:getProperty name="fBean" property="personalizationInfo" /> 

……