javaWeb初识 Session持久化

Session方法
invalidate() 就是从session对象池中删除session
isNew() boolean； true刚刚创建的Session；false 不是新建的Session
session本地持久化

 只要正常途径关闭tomcat服务器 就会把session内容存储到本地 注意，如果你在session存放对象，那这个对象想存储在磁盘上必须实现接口 java.io.Serializable

 import javax.servlet.RequestDispatcher; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpSession; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; @WebServlet("/hello") public class B extends HttpServlet { @Override protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { HttpSession session = request.getSession(); Test test = new Test(); test.setName("小明"); session.setAttribute("Test", test);//通过对象的方式存储 RequestDispatcher requestDispatcher = request.getRequestDispatcher("a"); requestDispatcher.forward(request, response); } } ---- package com.sun.tomcat; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import java.io.IOException; import java.io.PrintWriter; import javax.servlet.http.HttpSession; @WebServlet("/a") public class A extends HttpServlet { @Override protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { HttpSession session = request.getSession(); Test test = (Test) session.getAttribute("Test"); //将对象进行强制类型转化 System.out.println(test.getName());//用转换后的对象进行取值 } } ---- package com.sun.tomcat; import java.io.Serializable; public class Test implements Serializable {//实现序列化技术 private String name; public String getName() { return name; } public void setName(String name) { this.name = name; } @Override public String toString() { return "Test{" + "name='" + name + '\'' + '}'; } }