Servlet 共享变量

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主要是教ServletContext，HttpSession，request的生存周期的，代码如下

SetShareVar.java

package test.demo1;import java.io.IOException;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;/** * Servlet implementation class SetShareVar */@WebServlet("/SetShareVar")public class SetShareVar extends HttpServlet {private static final long serialVersionUID = 1L;           /**     * @see HttpServlet#HttpServlet()     */    public SetShareVar() {        super();        // TODO Auto-generated constructor stub    }/** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stub//设置共享变量//1.ServletContext//2.HttpSession//3.HttpServletRequestServletContext ctx=this.getServletContext();ctx.setAttribute("ctx_name", "ctx_value");HttpSession session=request.getSession();session.setAttribute("session_name", "session_value");request.setAttribute("request_name", "request_value");request.getRequestDispatcher("GetSharedRequest").forward(request, response);}/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubdoGet(request, response);}}

GetSharedRequest.java

package test.demo1;import java.io.IOException;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;/** * Servlet implementation class GetSharedRequest */@WebServlet("/GetSharedRequest")public class GetSharedRequest extends HttpServlet {private static final long serialVersionUID = 1L;           /**     * @see HttpServlet#HttpServlet()     */    public GetSharedRequest() {        super();        // TODO Auto-generated constructor stub    }/** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubServletContext ctx=this.getServletContext();HttpSession session=request.getSession();String ctx_name=(String)ctx.getAttribute("ctx_name");String session_name=(String)session.getAttribute("session_name");String request_name=(String)request.getAttribute("request_name");System.out.println("ctx:"+ctx_name);System.out.println("session:"+session_name);System.out.println("request:"+request_name);}/** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// TODO Auto-generated method stubdoGet(request, response);}}

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