如何在 web.xml 中配置欢迎文件列表 [英] How to configure welcome file list in web.xml

问题描述

我的 web.xml 文档中有这个.我正在尝试使用欢迎列表，因此我不再需要键入主页的路径.但是每次在我的 tomcat 页面中单击该应用程序时，它都会显示请求的资源不可用.

I have this in my web.xml document. I am trying to have a welcome list so I dont need to type the path for the home page anymore. But everytime a clicked the application in my tomcat page it displays The requested resource is not available.

<listener>
    <listener-class>web.Init</listener-class>
</listener>

<welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
</welcome-file-list>

<servlet>
    <servlet-name>index</servlet-name>
    <servlet-class>web.IndexServlet</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>index</servlet-name>
    <url-pattern>/index</url-pattern>
</servlet-mapping>

我的jsp页面的servlet

My servlet for the jsp page

package web;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.log4j.Logger;

public class IndexServlet extends HttpServlet
{
    private Logger logger = Logger.getLogger(this.getClass());
    private RequestDispatcher jsp;

    public void init(ServletConfig config) throws ServletException
    {
        ServletContext context = config.getServletContext();
        jsp = context.getRequestDispatcher("/WEB-INF/jsp/index.jsp");
    }

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException
    {
        logger.debug("doGet()");
        jsp.forward(req, resp); 
    }
}

为什么它仍然不起作用?我仍然需要在我的 url 中输入/index...如何正确地做到这一点?

Why is that it is still not working?I still need to type the /index in my url...How to do this correctly?

推荐答案

你需要把JSP文件放在/index.jsp而不是/WEB-INF/jsp/index.jsp.顺便说一下，这样整个 servlet 是多余的.

You need to put the JSP file in /index.jsp instead of in /WEB-INF/jsp/index.jsp. This way the whole servlet is superflous by the way.

WebContent
 |-- META-INF
 |-- WEB-INF
 |    `-- web.xml
 `-- index.jsp

如果您绝对肯定需要以这种奇怪的方式调用 servlet，那么您应该将它映射到 /index.jsp 而不是 /index.您只需要更改它以从 request 而不是从 config 获取请求调度程序并摆脱整个 init() 方法.

If you're absolutely positive that you need to invoke a servlet this strange way, then you should map it on an URL pattern of /index.jsp instead of /index. You only need to change it to get the request dispatcher from request instead of from config and get rid of the whole init() method.

如果您真的打算拥有一个主页 servlet"(因此不是欢迎文件—它具有完全不同的目的；即当folder 被请求，因此它不是特定的根文件夹)，那么您应该将 servlet 映射到空字符串 URL 模式.

In case you actually intend to have a "home page servlet" (and thus not a welcome file — which has an entirely different purpose; namely the default file which sould be served when a folder is being requested, which is thus not specifically the root folder), then you should be mapping the servlet on the empty string URL pattern.

<servlet-mapping>
    <servlet-name>index</servlet-name>
    <url-pattern></url-pattern>
</servlet-mapping>

另见servlet映射url中/和/*的区别模式.

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