JavaWeb基础 ServletContext getInitParameterNames 读取全局初始变量

Posted 2020-10-11

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       javaEE：7           
       javaSE：1.8
          JSTL：1.2.2  
      server：tomcat 8.5
    explorer：Firefox        
             os：windows7 x64
            ide：MyEclipse 2017

工程目录结构

 

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">


	<servlet>
		<servlet-name>ReadInitDataServletContext</servlet-name>
		<servlet-class>jizuiku.web.servlet.ReadInitDataServletContext</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>ReadInitDataServletContext</servlet-name>
		<url-pattern>/ReadInitDataServletContext</url-pattern>
	</servlet-mapping>
	
	<context-param>
		<param-name>minNum</param-name>
		<param-value>10</param-value>
	</context-param>
	
	<context-param>
		<param-name>count</param-name>
		<param-value>100</param-value>
	</context-param>
	
	<context-param>
		<param-name>maxNum</param-name>
		<param-value>1000</param-value>
	</context-param>
	
</web-app>

 

代码

package jizuiku.web.servlet;

import java.io.IOException;
import java.util.Enumeration;

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

/**
 * 读取 所有 全局初始化变量的名称和值
 * 
 * @author 给最苦
 * @version V17.10.21
 */
public class ReadInitDataServletContext extends HttpServlet {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// TODO Auto-generated method stub
		ServletContext application = this.getServletContext();
		Enumeration<String> e = application.getInitParameterNames();
		String name = null;
		while (e.hasMoreElements()) {
			name = e.nextElement();
			System.out.println(name + " : " + application.getInitParameter(name));
		}
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// TODO Auto-generated method stub

	}
}

 
效果

 

 

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