package cookie.test;
import java.io.IOException;
import java.io.PrintWriter; import java.util.LinkedHashMap; import java.util.Map;import javax.servlet.ServletException;
import javax.servlet.http.Cookie; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse;public class CookieDemo3 extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {response.setCharacterEncoding("UTF-8");
response.setContentType("text/html);charset=UTF-8"); PrintWriter out = response.getWriter(); //输出网站商品 out.write("本网站有如下书籍:<br/>"); Map<String,Book> map = Db.getAll(); for(Map.Entry<String,Book>entry:map.entrySet()) { Book book = entry.getValue(); out.println("<a href='/cookie/servlet/CookieDemo4?id="+book.getId()+"' target='_blank'>"+book.getName()+"</a><br/>"); } //2,显示用户看过的商品 out.print("<br/>您曾经浏览过的商品：<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 = Db.getAll().get(id); out.print(book.getName()+"<br/>"); } } } }public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {}
}
class Db{
//private Map map = new HashMap(); private static Map<String,Book> map = new LinkedHashMap<String,Book>(); static { map.put("1",new Book("1","水浒传","施耐庵","名著")); map.put("2",new Book("2","三国演义","罗贯中","名著")); map.put("3",new Book("3","西游记","吴承恩","名著")); map.put("4",new Book("4","红楼梦","曹雪芹","名著")); map.put("5",new Book("5","文章中含有违禁内容: 金！瓶！梅！","笑笑生","名著")); } public static Map<String, Book> getAll() { return map; } }class Book{
private String id; private String name; private String author; private String description; public Book() { super(); // TODO Auto-generated constructor stub } public Book(String id, String name, String author, String description) { super(); this.id = id; this.name = name; this.author = author; this.description = description; } 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; } public String getAuthor() { return author; } public void setAuthor(String author) { this.author = author; } public String getDescription() { return description; } public void setDescription(String description) { this.description = description; }}
package cookie.test;
import java.io.IOException;
import java.io.PrintWriter; import java.util.Arrays; import java.util.LinkedList; 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; //显示商品详细信息的servlet public class CookieDemo4 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {response.setCharacterEncoding("UTF-8");
response.setContentType("text/html);charset=UTF-8"); PrintWriter out = response.getWriter();//根据用户带过来的id，显示相应商品的详细信息
String id = request.getParameter("id"); Book book = (Book)Db.getAll().get(id); out.write(book.getId() + "<br/>"); out.write(book.getName() + "<br/>"); out.print(book.getAuthor() + "<br/>");/ out.write(book.getDescription() + "<br/>"); //构建cookie String cookieValue= buildCookie(id,request); Cookie cookie = new Cookie("bookHistory",cookieValue); cookie.setMaxAge(3600*24*30); cookie.setPath("/cookie"); response.addCookie(cookie); }private String buildCookie(String id, HttpServletRequest request) {
//bookHistory = null
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); } list.addFirst(id); StringBuffer sb = new StringBuffer(); for(String bid : list) { sb.append(bid + ","); } return sb.deleteCharAt(sb.length()-1).toString(); /*Cookie cookie[] = request.getCookies(); for(Cookie c:cookie) { if(c.getName().equals("bookHistory")) { String str = c.getValue(); if(str.matches(".+"+id+".+")) { str = str.replace(",?"+id+",?",","); str = str + id; }else { str = str+","+id; } return str; } }return id;*/
}public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
}
}