Java 手动生成面上下文

我有两个系统要整合。一个是基于原始servlet构建的，另一个是基于JSF和IceFaces构建的。我正在努力促进跨系统登录。我的想法是，我在旧系统中有一个按钮，可以将适当的信息发布到新站点并登录

理想情况下，我只想使用一个常规的旧servlet来在新站点上实现这一点。转到新站点的Servlet，做它需要做的事情，并将其转发到仪表板上

我们的安全性是通过托管bean处理的。但是，当您到达Servlet时，没有faces上下文。那么，我如何创建一个新的faces上下文呢

我有一个备份计划，我总是可以链接到一个虚拟的.iface页面，该页面将为我创建FacesContext，然后创建一个备份bean，当它被实例化时，它将做一些事情，然后转发到主页上。但这感觉很像黑客

任何帮助都将不胜感激

编辑：我选择了备份方式。基本上，我发布到这样一个页面：

<f:view>
   <ice:outputText value="#{EntryPoint}"/>
</f:view

这仍然感觉像是一个黑客，但我不知道如何摆脱这一点。理想情况下，我会发布到servlet，获取loginID，构建用户并将其直接放入托管bean中。但是，此时不存在FacesContext

---

还有其他想法吗？

我不知道你在这里所说的“站点”是什么意思

几点注意：

• 托管bean在定义它们的web应用（WAR）之外永远不可用
• FacesContext对象实例最终由创建和处理，因此请求应该通过这个servlet。在其他情况下尝试创建上下文可能会导致未定义的行为

---

记住这一点，您可以创建如下请求序列：

FacesServlet (mapping: /faces/*)
 -> /faces/jsfPage.jsp (a JSP with JSF controls)
    -> DispatchBean (calls ExternalContext.dispatch("/AnotherServlet")
       -> AnotherServlet

public class ContextServlet extends javax.servlet.http.HttpServlet implements
        javax.servlet.Servlet {
    static final long serialVersionUID = 1L;

    private FacesContextFactory facesContextFactory;
    private Lifecycle lifecycle;

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config);

        LifecycleFactory lifecycleFactory = (LifecycleFactory) FactoryFinder
                .getFactory(FactoryFinder.LIFECYCLE_FACTORY);
        facesContextFactory = (FacesContextFactory) FactoryFinder
                .getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);
        lifecycle = lifecycleFactory
                .getLifecycle(LifecycleFactory.DEFAULT_LIFECYCLE);
    }

    @Override
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {

        FacesContext context = facesContextFactory.getFacesContext(
                getServletContext(), request, response, lifecycle);
        try {
            ELContext elContext = context.getELContext();
            ExpressionFactory expressionFactory = context.getApplication()
                    .getExpressionFactory();
            ValueExpression expression = expressionFactory
                    .createValueExpression(elContext, "#{myBean.text}",
                            Object.class);
            Object value = expression.getValue(elContext);

            PrintWriter pw = response.getWriter();
            try {
                pw.write("" + value);
            } finally {
                pw.close();
            }
        } finally {
            context.release();
        }
    }

}

jsfPage.jsp包含：

<f:view>
    <h:outputText value="#{dispatchBean.dispatch}" />
</f:view>

发送到此servlet的：

public class FacesClientServlet extends javax.servlet.http.HttpServlet
        implements javax.servlet.Servlet {

    static final long serialVersionUID = 1L;

    @Override
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {

        FacesContext context = FacesContext.getCurrentInstance();
        ELContext elContext = context.getELContext();
        ExpressionFactory expressionFactory = context.getApplication()
                .getExpressionFactory();
        ValueExpression expression = expressionFactory.createValueExpression(
                elContext, "#{myBean.text}", Object.class);
        Object value = expression.getValue(elContext);

        ResponseWriter writer = context.getResponseWriter();
        writer.write("" + value);

    }

}

它从托管bean“myBean”发出值：

这一切都非常复杂，我不愿意做任何事情

---

另一种可能会带来自身后果的方法是创建自己的上下文，如下所示：

FacesServlet (mapping: /faces/*)
 -> /faces/jsfPage.jsp (a JSP with JSF controls)
    -> DispatchBean (calls ExternalContext.dispatch("/AnotherServlet")
       -> AnotherServlet

public class ContextServlet extends javax.servlet.http.HttpServlet implements
        javax.servlet.Servlet {
    static final long serialVersionUID = 1L;

    private FacesContextFactory facesContextFactory;
    private Lifecycle lifecycle;

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config);

        LifecycleFactory lifecycleFactory = (LifecycleFactory) FactoryFinder
                .getFactory(FactoryFinder.LIFECYCLE_FACTORY);
        facesContextFactory = (FacesContextFactory) FactoryFinder
                .getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);
        lifecycle = lifecycleFactory
                .getLifecycle(LifecycleFactory.DEFAULT_LIFECYCLE);
    }

    @Override
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {

        FacesContext context = facesContextFactory.getFacesContext(
                getServletContext(), request, response, lifecycle);
        try {
            ELContext elContext = context.getELContext();
            ExpressionFactory expressionFactory = context.getApplication()
                    .getExpressionFactory();
            ValueExpression expression = expressionFactory
                    .createValueExpression(elContext, "#{myBean.text}",
                            Object.class);
            Object value = expression.getValue(elContext);

            PrintWriter pw = response.getWriter();
            try {
                pw.write("" + value);
            } finally {
                pw.close();
            }
        } finally {
            context.release();
        }
    }

}

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同样，如果可能的话，我会避免这种方法。

第二个是我一直在寻找的答案，第一个是我的备用计划，如果我不能找到第一个。当时的想法是，遗留Servlet站点（它自己的webapp和WAR文件）将使用POST和凭据将用户重定向到新的webapp。有更好的方法吗？

public class ContextServlet extends javax.servlet.http.HttpServlet implements
        javax.servlet.Servlet {
    static final long serialVersionUID = 1L;

    private FacesContextFactory facesContextFactory;
    private Lifecycle lifecycle;

    @Override
    public void init(ServletConfig config) throws ServletException {
        super.init(config);

        LifecycleFactory lifecycleFactory = (LifecycleFactory) FactoryFinder
                .getFactory(FactoryFinder.LIFECYCLE_FACTORY);
        facesContextFactory = (FacesContextFactory) FactoryFinder
                .getFactory(FactoryFinder.FACES_CONTEXT_FACTORY);
        lifecycle = lifecycleFactory
                .getLifecycle(LifecycleFactory.DEFAULT_LIFECYCLE);
    }

    @Override
    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {

        FacesContext context = facesContextFactory.getFacesContext(
                getServletContext(), request, response, lifecycle);
        try {
            ELContext elContext = context.getELContext();
            ExpressionFactory expressionFactory = context.getApplication()
                    .getExpressionFactory();
            ValueExpression expression = expressionFactory
                    .createValueExpression(elContext, "#{myBean.text}",
                            Object.class);
            Object value = expression.getValue(elContext);

            PrintWriter pw = response.getWriter();
            try {
                pw.write("" + value);
            } finally {
                pw.close();
            }
        } finally {
            context.release();
        }
    }

}