使用浏览器后退按钮时重定向副作用

Question

我们正在使用:

• JSF 1.2-1.2_07-b03-FCS
• JSTL 1_1-mr2(特别版)
• Java 1.6.0_22-b04
• Eclipse 3.6.0(Helios)
• Tomcat 6.0.28(也需要在Weblogic上运行)
• IE 7.0.5730.13
• Firefox:6.0

我们有mainForm.jsp,filterForm.jsp和externalForm.jsp意见.

有一个按钮"过滤器"打开mainForm.jsp过渡到filterForm.jsp.它通过导航规则执行此操作:

<h:commandButton value="Filter" action="#{mainBean.filterData}" />

该mainBean.java代码是:

public String filterData() {
    doStuff();
    return "filter";
}

这最初正确地转换为filterForm.jsp.我们可以回到mainForm.jsp浏览器后退按钮.我们可以反复这样做.

在mainForm.jsp我们有一个表(实际上是一个ILog的甘特图,但我们不认为事项),与上图巴的"弹出"菜单.其中一个菜单选项是重定向到externalForm.jsp.

选择"重定向"会触发以下方法mainBean.java:

public void redirect(FacesMenuActionEvent event) {
    if (svr == null) {
        svr = new SetupURL(); // Simple code to set up the full URL
    }

    redirectUrl = svr.redirect(event);  // URL of externalForm.jsp
    svr.redirectData(redirectUrl);
}

这是正确的.窗口转换为externalForm.jsp.

如果我们按下浏览器后退按钮externalForm.jsp,我们会转换回来,mainForm.jsp看起来不错.

如果我们然后按"过滤器"按钮,代码不会执行该filterData()方法,而是执行该redirect()方法,我们转换到externalForm.jsp视图,而不是filterForm.jsp视图.

为什么会这样做？我们如何强制拨打电话filterData()呢？

******************************************************************************

BalusC - thank you for your solution.  With a few slight tweeks, it worked great.

The changes I made to web.xml are:

    <filter>
       <filter-name>noCacheFilter</filter-name>
       <filter-class>{my package name}.CacheControlFilter</filter-class>
    </filter>
    <filter-mapping>
       <filter-name>noCacheFilter</filter-name>
       <url-pattern>/faces/*</url-pattern>
    </filter-mapping>




Also, I found another solution:

faces-config.xml add:

    <lifecycle>
        <phase-listener id="nocache">{my package name}.
        CacheControlPhaseListener</phase-listener>
    </lifecycle>    


Create file CacheControlPhaseListener.java:

package {my package name};

import javax.faces.context.FacesContext;
import javax.faces.event.PhaseEvent;
import javax.faces.event.PhaseId;
import javax.faces.event.PhaseListener;
import javax.servlet.http.HttpServletResponse;

public class CacheControlPhaseListener implements PhaseListener {

    public PhaseId getPhaseId() {
        return PhaseId.RENDER_RESPONSE;
    }

    public void afterPhase(PhaseEvent event) {
    }

    public void beforePhase(PhaseEvent event) {
        FacesContext facesContext = event.getFacesContext();
        HttpServletResponse response = (HttpServletResponse) facesContext
                .getExternalContext().getResponse();
        response.addHeader("Pragma", "no-cache");
        response.addHeader("Cache-Control", "no-cache");
        // Stronger according to blog comment below that references HTTP spec
        response.addHeader("Cache-Control", "no-store");
        response.addHeader("Cache-Control", "must-revalidate");
        // some date in the past
        response.addHeader("Expires", "Mon, 8 Aug 2006 10:00:00 GMT");
    }
}

Both seem to work.



Thanks,
John

Answer 1

浏览器后退按钮从浏览器缓存中请求结果页面.它不会从服务器请求新的新页面.在您的特定情况下,缓存页面很可能包含当前无效的JSF视图状态.

最好的解决方法是指示浏览器不缓存动态JSF页面,而是每次都直接从服务器请求它.你可以Filter在doFilter()方法的帮助下做到这一点:

@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws ServletException, IOException {
    HttpServletResponse res = (HttpServletResponse) response;
    res.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1.
    res.setHeader("Pragma", "no-cache"); // HTTP 1.0.
    res.setDateHeader("Expires", 0); // Proxies.
    chain.doFilter(request, response);
}

此地图在同一<servlet-name>中的FacesServlet在web.xml.例如

<filter>
   <filter-name>noCacheFilter</filter-name>
   <filter-class>com.example.NoCacheFilter</filter-class>
</filter>
<filter-mapping>
   <filter-name>noCacheFilter</filter-name>
   <servlet-name>facesServlet</servlet-name>
</filter-mapping>