登錄JSP和servlet連接到數據庫

Question

我有一個JSP登錄頁面，我在其中輸入用戶名和密碼，並將它們傳遞給我的servlet，該servlet使用psaviour數據庫中的用戶表驗證它們，然後成功或失敗時，應將其轉發到歡迎頁面或返回登錄頁面。

然而，我試圖從我的checklogin servlet連接到我的數據庫。

import java.io.IOException; 
    import java.io.PrintWriter; 
    import java.sql.Connection; 
    import java.sql.DriverManager; 
    import java.sql.PreparedStatement; 
    import java.sql.ResultSet; 
    import java.sql.SQLException; 
    import javax.servlet.ServletException; 
    import javax.servlet.annotation.WebServlet; 
    import javax.servlet.http.HttpServlet; 
    import javax.servlet.http.HttpServletRequest; 
    import javax.servlet.http.HttpServletResponse; 


    @WebServlet(urlPatterns = {"/checkLogin"}) 
    public class checkLogin extends HttpServlet { 

     private final String DB_URL = "jdbc:mysql://localhost:3306/psaviour"; 
     private final String JDBC_DRIVER="com.mysql.jdbc.Driver"; 
     private final String USER = "root"; 
     private final String PASS = "root"; 
     Connection conn; 
     PreparedStatement stmt = null; 
     ResultSet rs = null; 



    @Override 
    protected void doPost(HttpServletRequest request, HttpServletResponse 
    response) 
    throws ServletException, IOException { 
     response.setContentType("text/html;charset=UTF-8"); 
     PrintWriter out = response.getWriter();  
     String username = request.getParameter("username");//.toString(); 
     String passkey = request.getParameter("passkey");//.toString(); 

     try { 
      Class.forName(JDBC_DRIVER); 
      try { 
       conn = DriverManager.getConnection(DB_URL, USER, PASS); 
       stmt=conn.prepareStatement("SELECT * FROM users WHERE 'username' = 
       ? AND 'passkey' = ?"); 
       stmt.setString(1, username); 
       stmt.setString(2, passkey); 
       rs = stmt.executeQuery(); 
      } catch (SQLException e){ 
       e.printStackTrace(); 
      } catch (ClassNotFoundException ce){ 
       ce.printStackTrace(); 
      } 
     } 
     while (rs.next()){ 
      //need to point to my welcome.jsp page or 
     } 
     //otherwise reload login page.... 
    }  
} 

Answer 1

這個怎麼樣？

if (rs.next()){ 
    //need to point to my welcome.jsp page or 
    RequestDispatcher dispatch = request.getRequestDispatcher("/welcome.jsp"); 
    dispatch.forward(request, response); 
} else { 
    //otherwise reload login page.... 
    request.setAttribute("errorMessage", "Authentication failure!"); 
    response.sendRedirect("/login"); 
}