web一些实验代码——会话管理
实验5：会话管理
1、新建HelloServlet1代码，熟悉Cookie的创建、获取与相关操作。
package com.example.weeebbbb.the5.cookie;
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.text.SimpleDateFormat;
import java.util.Date;
@WebServlet(name = "HelloServlet1", value = "/HelloServlet1")
public class HelloServlet1 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
response.setContentType("text/html;charset=utf-8");
String lastAccessTime=null;
//通过request调用getCookies获取cookie
Cookie[] cookies=request.getCookies();
for(int i=0;cookies!=null && i第一次访问 ：
第二次访问：
2、完成以下实验步骤，实现简单的购书操作。
（1）新建Book.java：用于封装图书的信息。
package com.example.weeebbbb.the5.session;
public class Book {
private String id;
private String name;
public Book(String id,String name){
this.id=id;
this.name=name;
}
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
（2）新建BookDB.java：用于模拟保存所有图书的数据库。通过Map集合存储了多个不同的Book对象，提供了获取指定图书和所有图书的相关方法。
package com.example.weeebbbb.the5.session;
import java.util.Collection;
import java.util.LinkedHashMap;
import java.util.Map;
public class BookDB {
private static Map books=new LinkedHashMap();
static {
books.put("1",new Book("1","JavaWeb开发"));
books.put("2",new Book("2","JDBC开发"));
books.put("3",new Book("3","Java基础"));
books.put("4",new Book("4","Spring开发"));
books.put("5",new Book("5","Struts开发"));
}
public static Collection getAll(){
return books.values();
}
public static Book getBook(String id){
return books.get(id);
}
}
（3）新建ListBookServlet代码，用于显示所有可购买图书的列表，通过点击“购买”链接，便可将指定的图书添加到购物车中。遍历所有书籍，并将url设置为PurchaseServlet+书号；
package com.example.weeebbbb.the5.session;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Collection;
@WebServlet(name = "ListBookServlet", value = "/ListBookServlet")
public class ListBookServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out=response.getWriter();
Collection books=BookDB.getAll();
out.write("本站的图书有：
");
for(Book book:books){
//遍历所有书籍，并将url设置为PurchaseServlet+书号
String url="/weeebbbb_war_exploded/PurchaseServlet?id="+book.getId();
out.write(book.getName()+"点击购买
");
}
}
}
（4）新建PurchaseServlet代码，通过cookie共享数据，有两个功能，一是将用户购买的图书信息保存到Session对象中，二是在用户购买图书结束后，将页面重定向到用户已经购买的图书列表。；
package com.example.weeebbbb.the5.session;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
@WebServlet(name = "PurchaseServlet", value = "/PurchaseServlet")
public class PurchaseServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String id = request.getParameter("id");
if (id == null) {
String url = "ListBookServlet";
response.sendRedirect(url);
return;
}
Book book = BookDB.getBook(id);
//通过request获取session
HttpSession session = request.getSession();
List cart = (List) session.getAttribute("cart");
//通过session获取属性名cart的属性值
if (cart == null) {
cart = new ArrayList();
//通过session设置cart的属性值
session.setAttribute("cart", cart);
}
cart.add(book);
//创建cookie,并存入JSESSIONID
Cookie cookie = new Cookie("JSESSIONID", session.getId());
cookie.setMaxAge(60 * 30);
cookie.setPath("/");
//通过response对象将cookie发送到浏览器
response.addCookie(cookie);
String url = "CartServlet";
//通过response对象重定向到url指定的位置
response.sendRedirect(url);
}
}
（5）新建CartServlet通过cookie获取共享的数据，用于展示用户已经购买的图书列表。该类在实现时，需要通过getSession()获取到所有的Session对象，然后判断用户是否已经购买图书，如果已经购买过，则显示购买的图书列表，否则在页面显示友好的提示“对不起！您还没有购买任何商品”。
package com.example.weeebbbb.the5.session;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;
@WebServlet(name = "CartServlet", value = "/CartServlet")
public class CartServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
PrintWriter out=response.getWriter();
List cart=null;
boolean purFlag=true;
//通过request获取session
HttpSession session=request.getSession(false);
if(session==null){
purFlag=false;
}else{
//通过session 获取cart对应的属性值
cart=(List)session.getAttribute("cart");
if (cart==null){
purFlag=false;
}
}
if(!purFlag){
out.write(("对不起，您没有购买任何商品！
"));
}else{
out.write("您购买的图书有：
");
for (Book book:cart){
out.write(book.getName()+"
");
}
}
}
}
打开listbook：
点击购买：
3、使用session和cookie，实现用户一定时间内免登录。
（1）新建login.html页面
Title
（2）新建IndexServlet.java代码
package com.example.weeebbbb.the5.session;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;
@WebServlet(name = "IndexServlet",value = "/IndexServlet")
public class IndexServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
resp.setContentType("text/html;charset=utf-8");
HttpSession session= req.getSession(false);
if (null==session||!"叶兹".equals(session.getAttribute("username"))){
resp.sendRedirect("login1.html");
}else{
String html=""+"欢迎"+session.getAttribute("username")+"登陆成功！！
";
html+="退出登录";
resp.getWriter().append(html);
}
}
}
（3）新建LoginServlet1.java代码
package com.example.weeebbbb.the5.session;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;
@WebServlet(name = "LoginServlet1",value = "/LoginServlet1")
public class LoginServlet1 extends HttpServlet {
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
req.setCharacterEncoding("UTF-8");
String username=req.getParameter("username");
String password=req.getParameter("password");
if ("叶兹".equals(username)&&"123".equals(password)){
HttpSession session= req.getSession(true);
session.setMaxInactiveInterval(60*60);
session.setAttribute("username",username);
Cookie cookie=new Cookie("JSESSIONID",session.getId());
cookie.setMaxAge(60*60);
resp.addCookie(cookie);
resp.sendRedirect("/weeebbbb_war_exploded/IndexServlet");
}else{
resp.sendRedirect("login1.html");
}
}
}
（4）新建LogoutServlet.java代码
package com.example.weeebbbb.the5.session;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;
@WebServlet(name = "LogoutServlet",value = "/LogoutServlet")
public class LogoutServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
HttpSession session= req.getSession(false);
if (session!=null){
session.invalidate();
}
Cookie cookie=new Cookie("JSESSIONID","");
cookie.setMaxAge(0);
resp.addCookie(cookie);
resp.sendRedirect("/IndexServlet");
}
}
登录填写信息（注意这个登录的账号和密码是写死的，页面上输入的账号密码要和代码里写的一样才能成功登录，否则一直都会在登陆界面）：
登录成功：
