java - <error-page> web.xml 不工作

标签 java tomcat servlets exception

我正在尝试学习 JSP Servlet 中标签的用法，但遇到了一个问题。我已经在 web.xml 中提供了配置，但控件没有到达所需的位置。我从论坛上获取了这个示例代码。有人可以指导我哪里出错了。

MyExceptionServlet.java

package com.journaldev.servlet.exception;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/MyExceptionServlet")
public class MyExceptionServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    throw new ServletException("GET method is not supported.");
    }

}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"     xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">
  <display-name>ServletExceptionHandling</display-name>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
  </welcome-file-list>

  <error-page>
        <error-code>404</error-code>
    <location>/AppExceptionHandler</location>
  </error-page>

  <error-page>
      <exception-type>javax.servlet.ServletException</exception-type>
      <location>/AppExceptionHandler</location>
  </error-page>
</web-app>

AppExceptionHandler.java

package com.journaldev.servlet.exception;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet("/AppExceptionHandler")
public class AppExceptionHandler extends HttpServlet {
private static final long serialVersionUID = 1L;

protected void doGet(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException     {
    processError(request, response);
}

protected void doPost(HttpServletRequest request,
        HttpServletResponse response) throws ServletException, IOException {
    processError(request, response);
}

private void processError(HttpServletRequest request,
        HttpServletResponse response) throws IOException {
    // Analyze the servlet exception
    Throwable throwable = (Throwable) request
            .getAttribute("javax.servlet.error.exception");
    Integer statusCode = (Integer) request
            .getAttribute("javax.servlet.error.status_code");
    String servletName = (String) request
            .getAttribute("javax.servlet.error.servlet_name");
    if (servletName == null) {
        servletName = "Unknown";
    }
    String requestUri = (String) request
            .getAttribute("javax.servlet.error.request_uri");
    if (requestUri == null) {
        requestUri = "Unknown";
    }

    // Set response content type
      response.setContentType("text/html");

      PrintWriter out = response.getWriter();
      out.write("<html><head><title>Exception/Error Details</title></head><body>");
      if(statusCode != 500){
          out.write("<h3>Error Details</h3>");
          out.write("<strong>Status Code</strong>:"+statusCode+"<br>");
          out.write("<strong>Requested URI</strong>:"+requestUri);
      }else{
          out.write("<h3>Exception Details</h3>");
          out.write("<ul><li>Servlet Name:"+servletName+"</li>");
          out.write("<li>Exception Name:"+throwable.getClass().getName()+"</li>");
          out.write("<li>Requested URI:"+requestUri+"</li>");
          out.write("<li>Exception Message:"+throwable.getMessage()+"</li>");
          out.write("</ul>");
      }

      out.write("<br><br>");
      out.write("<a href=\"index.html\">Home Page</a>");
      out.write("</body></html>");
}
}

错误堆栈跟踪

Apr 23, 2014 11:30:18 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet   [com.journaldev.servlet.exception.MyExceptionServlet] in context with path [/ServletExceptionHandling] threw exception [GET method is not supported.] with root cause
javax.servlet.ServletException: GET method is not supported.
at com.journaldev.servlet.exception.MyExceptionServlet.doGet(MyExceptionServlet.java:15)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
at     org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:301)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:136)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:74)
at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:516)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1015)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:652)
at org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:222)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1575)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1533)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

通过查看错误堆栈跟踪，可以清楚地看出控件不会转到 web.xml 中指定的“/AppExceptionHandler”URL。

尝试访问 URL 时的 eclipse 浏览器快照:

**http://localhost:8081/ServletExceptionHandling/MyExceptionServlet**

enter image description here

通过浏览各种门户网站，我做了以下分析。 使用 3 以外的 servlet 版本时可能会出现此问题，但我检查了 tomcat 安装中捆绑的 servlet-api.jar 的 list 文件及其 规范标题:用于 Servlet 的 Java API 规范版本:3.1

有些论坛说是IE的问题，所以我在Mozialla，Eclipse浏览器上查了一下。我觉得 web.xml 中的错误标记没有被正确识别。否则 URL 会更改为其他内容。甚至堆栈跟踪也表明没有重定向到 AppExceptionHandler.java。

关于版本的更多信息

Eclipse Juno 服务版本 2 Tomcat 版本 8 JRE7 JDK1.7

在 eclipse 中请求目录结构。 enter image description here 请帮忙。

问候塔伦

最佳答案

部署在路径/foo 的 WAR 不支持重新加载

目前，当直接从 WAR 文件部署 Web 应用程序时，不支持应用程序重新加载(以获取对类或 web.xml 文件的更改)。它仅在从解压目录部署 Web 应用程序时有效。如果您使用的是 WAR 文件，您应该取消部署然后部署或使用更新参数再次部署应用程序以获取您的更改。

关于java - <error-page> web.xml 不工作，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/23236879/

上一篇：java - 使用 Intellij IDEA 在 tomcat 中重新加载 primefaces 文件

下一篇：java - 为什么我的OpenGrok全搜索总是出不到结果？

相关文章：

java - 从字符串输入中获取颜色

java - 如何在 Spring MVC Web 应用程序中从 Tomcat 自定义目录读取文件

java - Cloud Foundry 服务代理 - 实现 REST 端点

javascript - cocos2dJs 跨平台游戏语言更改期间设备崩溃(Android 平台)

Java-多边形和线的交点

java - 如何使 JTable 的标题透明

tomcat - Grails:Tomcat War 文件部署给出内存异常

领域的 Tomcat jdbc 连接 "nullpointerexception"

servlets - 将表单提交到与数据库交互的Servlet，结果显示在空白页中

java 小服务程序 : request parameter contains plus

©2024 IT工具网  联系我们