Session是否为新建情况的判断

Session是否为新建情况的判断：

Xml：

<?xml version="1.0" encoding="UTF-8"?>

<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee"

    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee

    http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">

    <display-name>TestBootWeb</display-name>

    <servlet>

        <servlet-name>TestServlet1</servlet-name>

        <servlet-class>com.stono.servlet.listenerorder.SessionON</servlet-class>

    </servlet>

    <servlet>

        <servlet-name>TestServlet2</servlet-name>

        <servlet-class>com.stono.servlet.listenerorder.SessionON2</servlet-class>

    </servlet>

    <servlet-mapping>

        <servlet-name>TestServlet1</servlet-name>

        <url-pattern>/a.do</url-pattern>

    </servlet-mapping>

    <servlet-mapping>

        <servlet-name>TestServlet2</servlet-name>

        <url-pattern>/b.do</url-pattern>

    </servlet-mapping>

    <welcome-file-list>

        <welcome-file>index.jsp</welcome-file>

    </welcome-file-list>

</web-app>

Servlet：

package com.stono.servlet.listenerorder;

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;

import javax.servlet.http.HttpSession;

public class SessionON extends HttpServlet {

    private static final long serialVersionUID = 1L;

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        HttpSession session = req.getSession();

        // 如果客户端的cookie禁用，每次获得的session都是新的；在chrome Developer Tools中的Cookies界面可以看到没有request的JSESSIONID；

        // 判断获得的session是否是新的；

        boolean new1 = session.isNew();

        System.out.println("session is " + new1);

        PrintWriter writer = resp.getWriter();

        writer.println("com.stono.servlet.listenerorder.SessionON.doGet(HttpServletRequest, HttpServletResponse)");

        resp.encodeURL("a.do");

    }

}

package com.stono.servlet.listenerorder;

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;

import javax.servlet.http.HttpSession;

public class SessionON2 extends HttpServlet {

    private static final long serialVersionUID = 1L;

    @Override

    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        // 获取已经存在的session；

        HttpSession session = req.getSession(false);

        // 这个session可能为null；

        boolean new1 = session.isNew();

        System.out.println("session is " + new1);

        PrintWriter writer = resp.getWriter();

        writer.println("com.stono.servlet.listenerorder.SessionON2.doGet(HttpServletRequest, HttpServletResponse)");

    }

}