会话结束：
浏览器关闭；
主动关闭；
会话超时；
会话的底层实现方法：
cookies；
URL重写；
Example：
DemoSessionServlet.java
代码：
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Date;
import java.util.Enumeration;
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 DemoSessionServlet extends HttpServlet {
private static final long serialVersionUID = 3144436730239445373L;
public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
HttpSession session = request.getSession();
Integer counter = (Integer) session.getAttribute("counter");
if (counter == null) {
counter = new Integer(1);
} else {
counter = new Integer(counter.intValue() + 1);
}
session.setAttribute("counter", counter);
session.setMaxInactiveInterval(3600);
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head><title>session demo servlet</title></head>");
out.println("<body>");
out.println("<h1>使用session的演示</h1>");
out.println("你已经访问了" + counter + "次.<br><br>");
if (session.isNew()) {
out.println("这是一个新建的Session.<br><br>");
} else {
out.println("这不是一个新建的Session.<br><br>");
}
out.println("jsessionid: " + session.getId() + "<br><br>");
out.println("LastAccessedTime: " + session.getLastAccessedTime() + "<br>");
out.println("格式转换以后的LastAccessedTime: " + new Date(session.getLastAccessedTime()) + "<br><br>");
out.println("CreationTime: " + session.getCreationTime() + "<br>");
out.println("格式转换以后的CreationTime: " + new Date(session.getCreationTime()) + "<br><br>");
out.println("MaxInactiveInterval: " + session.getMaxInactiveInterval() + "秒<br>");
out.println("<br>使用Session对象的getAttributeNames<br>");
Enumeration enumer = session.getAttributeNames();
String name = null;
while (enumer.hasMoreElements()) {
name = (String) enumer.nextElement();
out.println("Session name:" + name + "<br>");
out.println("Session value:" + session.getAttribute(name) + "<br>");
}
// session.removeAttribute("counter");
//移除或者注销session
// session.invalidate();
out.println("</body>");
out.println("</html>");
out.flush();
out.close();
}
}