Java_乔晓松_使用cookie显示曾经访问过的商品

package com.csdn.cookie;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.csdn.BookDao.BookDao;
import com.csdn.doMain.Book;

public class CookieDemo2 extends HttpServlet {


/**
* 
*/
private static final long serialVersionUID = 1L;


public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter pw = response.getWriter();
pw.print("所有的书:<br />");
BookDao bd = new BookDao();
List<Book> list = bd.getAll();
for(Book book:list){
pw.print("<a href='/Cookie/CookieDemo3?id="+book.getId()+"' target='_blank'>"+book.getName()+"</a><br/>");
}

pw.print("你浏览过的商品：<br/>");
Cookie[] cookies = request.getCookies();
for(int i=0;cookies!=null && i<cookies.length;i++){
if(cookies[i].getName().equals("bookhistory")){
String[] ids = cookies[i].getValue().split(",");
for(String id:ids){
Book book = bd.getBook(id);
pw.print(book.getName()+"<br/>");
}
}
}
}


public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

doGet(request, response);
}

}








package com.csdn.cookie;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.LinkedList;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.csdn.BookDao.BookDao;
import com.csdn.doMain.Book;

public class CookieDemo3 extends HttpServlet {


/**
* 
*/
private static final long serialVersionUID = 1L;


public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
PrintWriter pw = response.getWriter();
String id = request.getParameter("id");
BookDao bd = new BookDao();
Book book = bd.getBook(id);
//System.out.println(book);
pw.print("书号："+book.getId()+"<br/>");
pw.print("书名："+book.getName()+"<br/>");
pw.print("作者："+book.getAuthor()+"<br/>");
pw.print("描述："+book.getAssess()+"<br/>");

String cookieValue = buildCookValue(id,request);
Cookie cookie = new Cookie("bookhistory",cookieValue);
cookie.setMaxAge(30*24*3600);
cookie.setPath("/Cookie");
response.addCookie(cookie);
}

public String buildCookValue(String id,HttpServletRequest request){
String bookhistory=null;
Cookie[] cookies = request.getCookies();
for(int i=0;cookies!=null && i<cookies.length;i++){
if(cookies[i].getName().equals("bookhistory")){
bookhistory = cookies[i].getValue();
}
}
if(bookhistory == null){
return id;
}
LinkedList<String> list = new LinkedList<String>(Arrays.asList(bookhistory.split(",")));
if(list.contains(id)){
list.remove(id);
list.addFirst(id);
}else{
if(list.size()>=3){
list.removeLast();
list.addFirst(id);
}else{
list.addFirst(id);
}
}
StringBuffer sb= new StringBuffer();
for(String bid: list){
sb.append(bid+",");
}

return  sb.deleteCharAt(sb.length()-1).toString();
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {

doGet(request, response);
}

}