Question

我遇到了一个与bean类和session相关的问题带有一些私有字段和一些setter和getter的简单类方法和一个类与数据库的交互和另一个控制器，我面临的问题是在main上将用户值设置为null 任何人都可以帮助我，我在这里发布完整的代码 throgh login.jsp我正在传递价值并通过用户在jsp中记录我试图检索请任何人帮助我在这里。

public class ConnectionManager {

public static Connection getConnection(){
    Connection con=null;  
     try{

    Class.forName("com.mysql.jdbc.Driver");
con=(Connection) DriverManager.getConnection("jdbc:mysql://localhost/demo2","root","");


}catch(Exception  e){

}
return con; 
}} 
   public class LoginServlet extends HttpServlet {
    public void doGet(HttpServletRequest request, HttpServletResponse response) 
        throws ServletException, java.io.IOException {

   try
  {        

   UserBean user = new UserBean();
   user.setUserName(request.getParameter("un"));
   user.setPassword(request.getParameter("pw"));

 user = UserDAO.login(user);

 if (user.isValid())
 {

    HttpSession session = request.getSession();    

     session.setAttribute("currentSessionUser",user); 

      response.sendRedirect("userLogged.jsp");    

  }

  else 
      response.sendRedirect("invalidLogin.jsp");
   } 


  catch (Throwable theException)         
  {
   System.out.println(theException); 
  }
   }
  }         
   public class UserDAO     
  {
  static Connection currentCon = null;
  static ResultSet rs = null;  
    public static UserBean login(UserBean bean) {

  //preparing some objects for connection 
  Statement stmt = null;    

  String username = bean.getUsername();    
  String password = bean.getPassword();   

  String searchQuery =
        "select * from users where username='"
                 + username
                 + "' AND password='"
                 + password
                 + "'";
        try 
  {

   currentCon = ConnectionManager.getConnection();
  stmt=currentCon.createStatement();
  rs = stmt.executeQuery(searchQuery);            
  boolean more = rs.next();

   // if user does not exist set the isValid variable to false
    if (!more) 
   {
     System.out.println("Sorry, you are not a registered user! Please sign up first");
     bean.setValid(false);
  } 

  //if user exists set the isValid variable to true
  else if (more) 
  {
     String firstName = rs.getString("FirstName");
     String lastName = rs.getString("LastName");


     bean.setFirstName(firstName);
     bean.setLastName(lastName);
     bean.setValid(true);
  }
   } 

   catch (Exception ex) 
   {
  System.out.println("Log In failed: An Exception has occurred! " + ex);
   } 


  finally 
   {
  if (rs != null)    {
     try {
        rs.close();
     } catch (Exception e) {}
        rs = null;
     }

  if (stmt != null) {
     try {
        stmt.close();
     } catch (Exception e) {}
        stmt = null;
     }

  if (currentCon != null) {
     try {
        currentCon.close();
     } catch (Exception e) {
     }

     currentCon = null;
   }
 }

 return bean;

 }    
 }
   public class UserBean {

  private String username;
  private String password;
  private String firstName;
  private String lastName;
  public boolean valid;


   public String getFirstName() {
   return firstName;
  }

   public void setFirstName(String newFirstName) {
   firstName = newFirstName;
  }


   public String getLastName() {
   return lastName;
      }

 public void setLastName(String newLastName) {
     lastName = newLastName;
      }


   public String getPassword() {
   return password;
   }

   public void setPassword(String newPassword) {
   password = newPassword;
  }


   public String getUsername() {
     return username;
      }

    public void setUserName(String newUsername) {
     username = newUsername;
      }


   public boolean isValid() {
     return valid;
  }

   public void setValid(boolean newValid) {
   valid = newValid;
   }    
  } 

  /*login.jsp*/

   form action="LoginServlet"

        Please enter your username         
        input type="text" name="un"        

        Please enter your password
        input type="text" name="pw"

        input type="submit" value="submit"           

    /form


 /*userLogged.jsp*/
  html


 Welcome Pname:<%=request.getAttribute("user")%>
  /html

Answer 1

实际上，我只是在寻找语法。我知道了;这是......

   <p>first name: ${currentSessionUser.firstName}</p>

如何在bean类中传递会话值

1 个答案: