【JSP开发】ServletContext的传值取值

package cn.edu;


import java.io.IOException;
import java.io.PrintWriter;


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


/*
 * ServletContext域
 * 1.这是一个容器
 * 2.ServletContext域这句话说明了容器的作用范围，也就是应用程序范围
 * */


//通过ServletContext实现ServletDemo4与ServletDemo5的数据共享
public class ServletDemo4 extends HttpServlet {


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {


		String data="aaa";
		//给整个应用的容器中上传了一个名叫data的数据
		this.getServletContext().setAttribute("data", data);
	}


	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request,response);
	}


}

package cn.edu;


import java.io.IOException;
import java.io.PrintWriter;


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


public class ServletDemo5 extends HttpServlet {


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
        
		//从ServletContext()容器中取出ServletDemo4存入的名叫data的数据
		String vlaue=(String)this.getServletContext().getAttribute("data");
		System.out.println(vlaue);
	}




	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request,response);
	}


}