Application域
有效范围
当前web服务内,跨请求,跨会话
生命周期
创建 项目启动
使用 项目运行任何时间有效
销毁 项目关闭
测试代码
Application域中放入数据
package com.msb.testApplication;import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.io.IOException;import java.util.ArrayList;import java.util.Collections;import java.util.List;/** * @Author: Ma HaiYang * @Description: MircoMessage:Mark_7001 */@WebServlet(urlPatterns = "/addToApplication.do")public class Servlet1 extends HttpServlet { @Override protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { // 向Application域中添加数据 ServletContext application = req.getServletContext(); List<String> x=new ArrayList<>(); Collections.addAll(x, "a","b","c"); application.setAttribute("list", x); application.setAttribute("gender","girl"); application.setAttribute("name","晓明"); }}
Application域中读取数据
package com.msb.testApplication;import javax.servlet.ServletContext;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import java.io.IOException;import java.util.List;/** * @Author: Ma HaiYang * @Description: MircoMessage:Mark_7001 */@WebServlet(urlPatterns="/readFromApplication.do")public class Servlet2 extends HttpServlet { @Override protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { ServletContext application = this.getServletContext(); // 从application域中读取数据 List<String> list =(List<String>) application.getAttribute("list"); System.out.println(list); System.out.println(application.getAttribute("gender")); System.out.println(application.getAttribute("name")); }}