的問題,當我填寫它調用servlet,它顯示了正確的信息的形式,當用戶單擊後退按鈕似乎調用頁面上的servlet用值爲null。我如何使它重新加載頁面,以便用戶可以在表單中填充。的Java Servlet重定向到頁面自動調用其形式的servlet
SetTimeZone.xhtml
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>SetTimeZone</title>
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
</head>
<body>
<div>
<form name ="SetTimeZone" method="post" action="SetTimeZoneServlet">
Set Time Zone: <input type="text" name="timeZone"/><br></br><br></br>
<input type ="submit" value="Submit" name="submit"/>
</form>
</div>
</body>
public class SetTimeZoneServlet extends HttpServlet {
/**
* Handles the HTTP <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
TimeZoneBean bean = new TimeZoneBean();
String city = request.getParameter("timeZone");
bean.setCity(city);
String temp = bean.checkCity();
String value = "";
if ("error".equals(temp)) {
value = "Sorry no information is availible for " + city;
} else {
value = "The current time in " + city + " is " + bean.getTime();
}
try (PrintWriter out = response.getWriter()) {
response.setContentType("text/html;charset=UTF-8");
/* TODO output your page here. You may use following sample code. */
out.println("<!DOCTYPE html>");
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet OrderFormServlet</title>");
out.println("</head>");
out.println("<body>");
out.println("<p>" + value + "</p>");
out.println("<form name=\"SetTimeZone.xhtml\" method=\"post\" name=\""
+ "SetTimeZoneRedirectServlet\"> ");
out.println("<input type =\"submit\" value=\"Back\"/ name=\"back\">");
out.println("</form>");
out.println("</body>");
out.println("</html>");
}
}
public class SetTimeZoneRedirectServlet extends HttpServlet {
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code>
* methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.sendRedirect("SetTimeZone.xhtml");
}
}
輸出重定向返回的頁面後,我得到的是; 抱歉沒有信息可用於null。
以前我試過這個,當我更改GET時發生這個錯誤。 HTTP狀態405 - 此方法不支持HTTP方法GET –
您可以覆蓋servlet中的get方法並調用doPost(req,res);在重寫的doGet()方法內部 – visrey