java - 托管 Bean 注销不起作用

Question

在我的 java ee 应用程序中，我无法实现注销功能。这就是当我尝试实现它时发生的情况: 我有一个 header.xhtml，其中包含我的应用程序的 header css 部分: header.xhtml:(注销代码)

<div class="userid-link"><img src="images/app.png" alt=""/><p><a href="#{loginBean.logoutAction()}">Logout</a></p></div>

注销代码:loginBean.java

    public String logoutAction()
    {
        HttpServletRequest req=(HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest();
try{
    HttpSession session=req.getSession();
    session.invalidate();
      //  req.logout();
        }
catch(Exception e)
        {

        }
        return"equityVolume.xhtml";
    }

错误:

SEVERE: Error Rendering View[/ClientTemplate/userWatch.xhtml]
javax.el.ELException: /ClientTemplate/userWatch.xhtml @44,62 value="#{watchBean.ut}": java.lang.IllegalStateException: PWC3999: Cannot create a session after the response has been committed
    at com.sun.faces.facelets.el.TagValueExpression.getValue(TagValueExpression.java:114)

...
INFO: Exception when handling error trying to reset the response.
java.lang.IllegalStateException: PWC3999: Cannot create a session after the response has been committed
    at...

主页加载正确，但是当我尝试登录时，userWatch.xhtml 未正确呈现，我收到上述错误，CSS 也未应用。

watchBean.java

 public List<UserTrack> getUt() {
        HttpServletRequest req=(HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest();
    HttpSession session=req.getSession();// debugged and found that the session is null, this methos executes after login i.e. on the userWatch.xhtml that is redirected after login from homePage
    this.uname=(String)session.getAttribute("uname");
        ut=getAllUserTrack(uname);
    return ut;
    }

当我从 header.xhtml 中删除 logOutAction 方法调用时，一切正常，除了注销时出现 viewExpired 错误:

<div class="userid-link"><img src="images/app.png" alt=""/><p><a href="#/homePage">Logout</a></p></div>

如何解决？

Answer 1

如果您的 loginBean 是 SessionScoped 托管 Bean 并且注销方法是该托管 Bean 的方法，则使 session 无效:

public void logout() {
    // Invalidate session of a sessionscoped managed bean
    FacesContext.getCurrentInstance().getExternalContext().invalidateSession();
    try {
        // Redirect to page you want after logout
        FacesContext.getCurrentInstance().getExternalContext().redirect("<INSERT HERE THE PAGE YOU WANT TO REDIRECT(just the name like 'homepage')");

    } catch (IOException ex) {
        Logger.getLogger(TravelerSession.class.getName()).log(Level.SEVERE, null, ex);
    }

}

您可以在该方法上重定向到您想要的页面，也可以返回您想要访问的页面的名称。我觉得用bean的方法来做比较安全。

在网页上你应该有这样的内容:

<h:commandButton class="btn btn-info" action="#{loginBean.logout}" value="Log out" />