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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

工程目錄結構

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>

代碼

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;

/**
 * 讀取 所有 全局初始化變量的名稱和值
 * 
 * @author 給最苦
 * @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

學習資源：itcast和itheima視頻庫。如果您有公開的資源，可以分享給我的話，用您的資源學習也可以。
博文是觀看視頻後，融入思考寫成的。博文好，是老師講得好。博文壞，是 給最苦 沒認真。

JavaWeb基礎 ServletContext getInitParameterNames 讀取全局初始變量