Question

我想获取context.xml中的companyName值在编写下面提到的代码后，我得到null值

请帮我从context.xml获取价值。您甚至可以通过其他方式告诉context.xml

获取价值

注意：不要在web.xml

中写下参数

Context.xml（Tomcat 7）

<?xml version='1.0' encoding='utf-8'?>
<!--
  Licensed to the Apache Software Foundation (ASF) under one or more
  contributor license agreements.  See the NOTICE file distributed with
  this work for additional information regarding copyright ownership.
  The ASF licenses this file to You under the Apache License, Version 2.0
  (the "License"); you may not use this file except in compliance with
  the License.  You may obtain a copy of the License at

      http://www.apache.org/licenses/LICENSE-2.0

  Unless required by applicable law or agreed to in writing, software
  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  See the License for the specific language governing permissions and
  limitations under the License.
-->
<!-- The contents of this file will be loaded for each web application -->
<Context>

    <!-- Default set of monitored resources -->
    <WatchedResource>WEB-INF/web.xml</WatchedResource>

    <!-- Uncomment this to disable session persistence across Tomcat restarts -->
    <!--
    <Manager pathname="" />
    -->

    <!-- Uncomment this to enable Comet connection tacking (provides events
         on session expiration as well as webapp lifecycle) -->
    <!--
    <Valve className="org.apache.catalina.valves.CometConnectionManagerValve" />
    -->
<Parameter name="companyName" value="My Company, Incorporated"
          override="false"/> 

</Context>

JSP（index.jsp的）

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%
ServletContext sc= getServletContext();
String testNameValue = sc.getInitParameter("companyName");
%>
<input type="text" value="<%=testNameValue%>">
</body>
</html>

输出

在实施以下解决方案后更新

异常来了

Exception

Answer 1

您无法加载，因为context.xml是JNDI资源。请尝试以下方法：

Tomcat（context.xml）

<Parameter name="companyName" value="My Company, Incorporated" override="false"/>

Java Side

InitialContext context = new InitialContext();
Context xmlNode = (Context) context.lookup("java:comp/env");
String companyName = (String) xmlNode.lookup("companyName");

Spring Side HomeController.java

@Controller
@RequestMapping("/")
public class HomeController {

    @Autowired
    private ServletContext servletContext;

    @RequestMapping(method=RequestMethod.GET)
    public ModelAndView index(ModelAndView mav) throws Exception {
        String companyName = servletContext.getInitParameter("companyName");
        mav.setViewName("home/index");
        mav.addObject("companyName", companyName);
        return mav;
    }

    public void setServletContext(ServletContext servletContext) {
        this.servletContext = servletContext;
    }
}

查看方 index.jsp的

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>Home</title>
    </head>
    <body>
        <c:out value="${companyName}"/>
    </body>
</html>

上面的例子在我看来已经证明是成功的。我的脚本可以在运行时从context.xml文件中读取，如图所示。

Answer 2

<Environment name="companyName" value="My Company, Incorporated" 
type="java.lang.String" override="false"/>

比参数更适合我，因为后者正在投掷尝试使用javax.naming.NameNotFoundException: Name [companyName] is not bound in this Context. Unable to find [companyName].

获取值时String companyName = (String) xmlNode.lookup("companyName");

我想读取tomcat context.xml的参数

2 个答案: