从 servlet 过滤器获取托管 Bean（为空）[重复]

Question

我看过很多类似我的帖子，但没有一个能帮到我。

这是我的托管 bean，它是 sessionScoped，如果登录正常，它会重定向到索引页面，否则会显示错误

@ManagedBean
@SessionScoped
public class LoginBean implements Serializable  {
/**
 * 
 */
private static final long serialVersionUID = 1L;
private static final String[] users = {"anna:qazwsx","kate:123456"};

private String username;
private String password;

private boolean loggedIn     
public String doLogin() {
    for (String user: users) {
        String dbUsername = user.split(":")[0];
        String dbPassword = user.split(":")[1];

        // Successful login
        if (dbUsername.equals(username) && dbPassword.equals(password)) {
            loggedIn = true;
            return "/tmpl/home/index.xhtml?faces-redirect=true";
        }
    }

    // Set login ERROR
    FacesMessage msg = new FacesMessage("Login error!", "ERROR MSG");
    msg.setSeverity(FacesMessage.SEVERITY_ERROR);
    FacesContext.getCurrentInstance().addMessage(null, msg);

    return "/login/login.xhtml";
 }

 public boolean isLoggedIn() {
    return loggedIn;
 }
}

视图，这里一切正常，调用托管bean的doLogin方法

<h:form id="login-form">
 <h:messages />
 <h:outputText value="Nom d'utilisateur:"/>
 <h:inputText value="#{loginBean.username}" id="username"/>
 <br/>
 <h:outputText value="Mot de passe:"/>
 <h:inputSecret value="#{loginBean.password}" id="password"/>
 <br/>
 <h:commandButton id="button" value="Login" action="#{loginBean.doLogin}" />    
 <br/>
</h:form>

过滤器：如果用户通过身份验证，则 loginBean 不为 null 并且已记录

public class LoginFilter implements Filter {

public void doFilter(ServletRequest request, ServletResponse response,   FilterChain chain) throws IOException, ServletException {      
    HttpSession session = ((HttpServletRequest) request).getSession(false);
    LoginBean loginBean = (session != null) ? (LoginBean) session.getAttribute("loginBean") : null;


    if (loginBean!=null)
        System.out.println(loginBean.getUsername());

    if (loginBean == null || !loginBean.isLoggedIn()) {
        System.out.println("here agai");
        String contextPath = ((HttpServletRequest)request).getContextPath();
        ((HttpServletResponse)response).sendRedirect(contextPath + "/login/login.xhtml");
    }         
    chain.doFilter(request, response);             
  }
}

为什么我的托管 bean (loginBean) 为空？

Answer 1

您是否确认您使用的是正确的 SessionScoped 注释？

请看这里： JSF login filter, session is null