无法将JSP中的对象转换为Java对象

Question

I can not get this working and I dont know why...

• Inside my .jsp I want to check if the executing user has suffient rights to do so.
• the user object from the class user is one of the session attributes
• inside my .jsp file I get the Object from the session
• I then cast it into user

• then I can access its stored values (which is an array list)

• Then when I go and test my code I get the error listed below.

Any Idea how to solve this Problem??

user_management.jsp

<% 
    User user = (User) session.getAttribute("obj_user");
    boolean test = user.oe_fac_role_right.get(2).get(0).equals(1);
    if (test) { 
%>
- some html code will be displayed here is the user is allowed to see it
<%  }  %>

User class

public class User {
    int user_id;
    String username;
    List<List<Integer>> oe_fac_role_right = new ArrayList<List<Integer>>(4);

    public User(){}

    ....
    ....
}

Creation of User Object in login class:

User user = new User(user_id, username, user_rights);

Passing User Object to session:

session.setAttribute("obj_user", user);

Error message from Netbeans

 An error occurred at line: 14 in the jsp file: /user_management.jsp
 user cannot be resolved to a type

 Line 14 in this case is: User user = (User) session.getAttribute("obj_user");

Answer 1

Your line is having user starting with small letter but class name is User starting with capital letter.

change

user user = (user) session.getAttribute("obj_user");

to

User user = (user) session.getAttribute("obj_user");

Also make your class public and import your class in jsp as below

<%@ page import="yourPackage.User%>

if this is not working, let me know.

Answer 2

it does not have any imports as the classes are all in the default package, so they should be accessable

Incorrect . The unnamed package is not accessible from another package, and the unnamed package cannot be imported.

Since a JSP is compiled to a Java class in some package, it can never access a class in the unnamed package.

Solution: You have to declare a package for the User class, then import the class in the JSP.

See Import package with no name Java .