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處理servlet時出現空白屏幕。之前它給了我一些錯誤，但在代碼修復後，它停止給我錯誤，並開始給我一個空白的屏幕。處理servlet時獲取空白屏幕
JSP文件
<%--
Document : index
Created on : Oct 2, 2011, 3:59:35 PM
Author : Ankur
--%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>ABC Corporation</title>
<h1>Terminal Login</h1>
</head>
<body>
<form name="login" action="/WebAccount/LoginServlet?" method="post" />
Username: <input type="text" name="username" value=""/>
Password: <input type="text" name="password" value=""/>
<input type="submit" value="LOGIN"/>
Not User? Register Here: <input type="submit" action="/WebAccount/register.jsp" value="REGISTER">
</body>
</html>
Servlet的文件 公共類LoginServlet延伸的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, SQLException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
String usern = request.getParameter("username");
String passw = request.getParameter("password");
try {
Class.forName("com.mysql.jdbc.Driver");
String url = "jdbc:mysql://localhost:3306/account";
Connection conn = DriverManager.getConnection(url, "root", "school");
Statement statement = (Statement) conn.createStatement();
ResultSet rs = statement.executeQuery("SELECT * from Users where username='" + usern + "' and password='" + passw + "';");
String user, pass;
while (rs.next()) {
user = rs.getString("username");
pass = rs.getString("password");
if (usern.equals(user) && passw.equals(pass)) {
out.println("Success!");
conn.close();
}
}
if (!rs.next()) {
out.println("Login failed");
conn.close();
}
} catch (SQLException ex) {
throw new ServletException("Cannot Connect", ex);
} catch (ClassNotFoundException ex) {
throw new ServletException("Login failed", ex);
} finally {
out.close();
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</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 doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
processRequest(request, response);
} catch (SQLException ex) {
Logger.getLogger(LoginServlet.class.getName()).log(Level.SEVERE, null, ex);
}
}
/**
* 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 {
try {
processRequest(request, response);
} catch (SQLException ex) {
Logger.getLogger(LoginServlet.class.getName()).log(Level.SEVERE, null, ex);
}
}
/**
* Returns a short description of the servlet.
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
任何錯誤或變化？
整個HTML文件行這是非常不可能的，任何人將調試此代碼。您需要使用更多日誌記錄，調試或線路監控來查找您的問題。 – bmargulies