将简单的Portlet部署到Liferay-ClassCastException [英] Deploying a simple Portlet to Liferay - ClassCastException

问题描述

我正在将最基本的Portlet部署到Liferay:

I'm deploying the most basic Portlet possible to Liferay:

public class FirstPortlet extends GenericPortlet
{
    @RenderMode(name="VIEW")
    public void welcomeWelcome(RenderRequest request, 
            RenderResponse response) throws  
            PortletException, IOException
    {       
        PrintWriter out = response.getWriter();
        out.println ("This is a portlet, <em>within a Portal</em>");
    }
}

在部署时，我收到ClassCastException:

On deployment, I'm getting a ClassCastException:

 Caused by: java.lang.ClassCastException: FirstPortlet cannot be cast to javax.po
rtlet.Portlet

在Google搜索之后，似乎部署portlet.jar是一个错误-我确保我没有意外地这样做.

After Googling, it appears that deploying portlet.jar is a mistake - I've made sure I'm not accidentally doing this.

javax.portlet.Portlet由GenericPortlet实现，所有Portlet示例似乎都扩展了GenericPortlet，所以我认为可以.

javax.portlet.Portlet is implemented by GenericPortlet, and all Portlet examples seem to extend GenericPortlet so I assume that's ok.

任何人都可以帮忙吗?

推荐答案

javax.portlet.Portlet已实现 通过GenericPortlet，以及所有Portlet 例子似乎扩展了GenericPortlet 所以我认为没关系.

javax.portlet.Portlet is implemented by GenericPortlet, and all Portlet examples seem to extend GenericPortlet so I assume that's ok.

如果GenericPortlet实现Portlet，我的猜测是您遇到类加载器问题.该类在两个不同的类加载器中加载了两次，因此被认为是不同的.

If GenericPortlet implements Portlet, my guess is that you have a class loader issue. The class is loaded twice, in two different class loaders and are by consequence considered different.

在谷歌搜索后，似乎 部署portlet.jar是一个错误- 我确保我不会意外 这样做.

After Googling, it appears that deploying portlet.jar is a mistake - I've made sure I'm not accidentally doing this.

我仍然建议您仔细检查一下是否在某处两次加载了portlet.jar(或另一个包含Portlet的jar).可能的位置取决于您使用的容器(Tomcat?Glassfish?).

I would still suggest that you double check if you don't have portlet.jar (or another jar which contains Portlet) loaded twice somewhere. The possible locations depend on the container you are using (Tomcat? Glassfish? ).

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