Question

我需要有关servlet过滤器的帮助。

目前我们有针对Oracle SSO的ChangePassword servlet。我想拦截对这个servlet的任何调用，如果我的检查失败，我会尝试将响应返回给发送者（更改密码jsp）。另外，如果我的所有检查都没问题，我会将请求传递给ChangePassword servlet。此过滤器的一个要求是保留原始参数，如果我的任何检查失败，则将它们重新发送回初始jsp页面。

目前的doFilter方法是：

public void doFilter(ServletRequest request, ServletResponse response, 
                     FilterChain chain) throws IOException, 
                                               ServletException {


    // __TB__ 2009_11_06 added for customization
    String str_old_password = null;
    String str_new_password = null;
    String str_new_password_confirm = null;
    String str_action = null;
    String str_user = request.getParameterValues("p_username")[0];


    // __TB__ 2009_11_06 added for customization
    // Get the old password value
    try {
        str_old_password = request.getParameterValues("p_old_password")[0];
    } catch (Exception e) {
        str_old_password = "";
        logger.error("Problem s dohvaćanjem starog passworda za username: " + 
                     str_user);
        throw new IOException();
    }

    // Get the new password
    try {
        str_new_password = request.getParameterValues("p_new_password")[0];
    } catch (Exception e) {
        str_new_password = "";
        logger.error("Problem s dohvaćanjem novog passworda za username: " + 
                     str_user);
        throw new IOException();
    }

    // Get the new password confrimantion string
    try {
        str_new_password_confirm = 
                         request.getParameterValues("p_new_password_confirm")[0];
    } catch (Exception e) {
        str_new_password_confirm = "";
        logger.error("Problem s dohvaćanjem potvrde novog passworda za username: " + 
                     str_user);
        throw new IOException();
    }

    // Get the action string
    try {
        str_action = request.getParameterValues("p_action")[0];
    } catch (Exception e) {
        str_action = "OK";
    }

    if (logger.isDebugEnabled()) {
        logger.debug("Ulazak u RuPassFilter-doFilter za username: " + 
                     str_user);
    }

    // Prevent update if passwords are not equal and action is not equal OK
    if (str_new_password.toString().equals(str_new_password_confirm.toString()) && 
        str_action.equals("OK")) {
        try {
            if (logger.isDebugEnabled()) {
                logger.debug("Novi password i njegova potvrda odgovaraju jedno drugom za username: " + 
                             str_user);
            }
            //Run update and on any exception pass request to password change servlet except on MyException
            MyChecker mc = new MyChecker();

            if (logger.isDebugEnabled()) {
                logger.debug("Poziv check metode u RuPassFilter-u za username: " + 
                             str_user);
            }
            mc.check (str_user, str_old_password, str_new_password, 
                        _filterConfig.getServletContext());
            if (logger.isDebugEnabled()) {
                logger.debug("Odrađena check metoda u RuPassFilter-u za username: " + 
                             str_user);
            }
            //pass to servlet
            chain.doFilter(request, response);

        } catch (UtilException ue) {
            logger.error("Dogodio se UtileException za username: " + 
                         str_user);
            logger.error(ue.getLocalizedMessage());

            chain.doFilter(request, response);

        } catch (NamingException ne) {
            logger.error("Dogodio se NamingException za username: " + 
                         str_user);
            logger.error(ne.getLocalizedMessage());

            chain.doFilter(request, response);

        } catch (IOException ioe) {
            logger.error("Dogodio se IOException u RuPassFilter-u za username: " + 
                         str_user);
            logger.error(ioe.getLocalizedMessage());

            throw ioe;
        } catch (MyException me) {
            logger.error("Dogodio se MyException u RuPassFilter-u za username: " + 
                         str_user);
            logger.error(me.getLocalizedMessage());

            //!!!!!!!!!!!!
            // At this point I need return response back to sender !!!!!!!!!!!!
            //!!!!!!!!!!!!!
        }
    } else {
        if (logger.isDebugEnabled()) {
            logger.debug("Passwordi ne odgovraju jedna drugom ili je action različit od OK u RuPassFilter-u za username: " + 
                         str_user);

        }
        //!!!!!!!!!!!!
        // At this point I need return response back to sender !!!!!!!!!!!!
        //!!!!!!!!!!!!!
    }

    // Everything is OK
    chain.doFilter(request, response);
}

如果我的任何检查失败，MyCheck.check方法会抛出MyException。

我们的J2EE服务器是OC4J版本：10.1.2.0.2

Answer 1

您可以使用RequestDispatcher

RequestDispatcher rd = request.getRequestDispatcher("path_for_initial_jsp_page"); try{ MyCheck.check(); }catch(MyException me){ logger.error(me.getLocalizedMessage()); rd.include(request, response); }

调用RequestDispatcher.forward（）： 一旦您将来自Servlet A的请求转发到任何其他Servlet / JSP控件，就会从Servlet A转移到转发的patrty＆amp;对于该请求，它永远不会返回给A.

RequestDispatcher.include（）： 在包含你正在做的是如果Servlet A（上面的例子）包含其他Servlet / JSP（比如B或B.jsp）的响应那么暂时控制转到B或B.jsp（他们会生成响应）控制来回到A＆amp;生成的响应在A的响应中添加。

在servlet过滤器中拦截请求并有条件地向发送方返回响应

1 个答案: