『JavaWeb--クッキーを利用してユーザーの履歴閲覧を記録する』

コードは少ないが、多くの問題に直面している.いろいろ勉強になった気もします.

//    ，“  ”Servlet
package com.fenghuo.cookie;

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 BuyServlet extends HttpServlet {

	/**
	 *  Title：  cookie           
	 *  Copyright: Copyright (c) 2012
	 *  @author:   
	 *  @version 1.0 2012-09-14
	 */
	private static final long serialVersionUID = 4408943836189873374L;

	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();
	
		out.print("        ：(      )
");
		
		//  ”   “  
		Map map = DB.getAll();
		
		//    ，   id      ShowObject
		out.print("=========================
");
		for (int i = 1; i < map.size()+1; i++){
			out.print(""+map.get(i+"").getName()+"
");
		}
		
		//         
		out.print("         ：
");
		
		//       cookie ，    cookie  
		Cookie[] cookies = request.getCookies();
		for (int i = 0; cookies != null && i < cookies.length; i++){
			
			//       cookie
			if (cookies[i].getName().equals("historyCookie")){
				String[] ids = cookies[i].getValue().split("\\,");
				
				//  cookie    id，        
				for (String id : ids){
					out.print(""+map.get(id).getName()+"
");
				}
			}
		}
	}

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

		doGet(request, response);
	}
}

//     
class DB{
	private static LinkedHashMap map = new LinkedHashMap();
	static{
		map.put("1", new MyObject("1", "  ", "12.0", "        ！"));
		map.put("2", new MyObject("2", "  ", "5.0", "      ！"));
		map.put("3", new MyObject("3", "  ", "8.0", "   ，     ！"));
		map.put("4", new MyObject("4", "  ", "6.0", "       ！"));
		map.put("5", new MyObject("5", "  ", "18.0", "     ！"));
	}
	
	public static Map getAll(){
		return map;
	}
}
class MyObject{
	
	private String id;
	private String name;
	private String price;
	private String describe;
	
	public MyObject(String id, String name, String price, String describe) {
		super();
		this.id = id;
		this.name = name;
		this.price = price;
		this.describe = describe;
	}
	
	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 getPrice() {
		return price;
	}
	public void setPrice(String price) {
		this.price = price;
	}
	public String getDescribe() {
		return describe;
	}
	public void setDescribe(String describe) {
		this.describe = describe;
	}
}

//          Servlet
package com.fenghuo.cookie;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Arrays;
import java.util.LinkedList;
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 ShowObject extends HttpServlet {

	/**
	 *  Title：         ，    cookie
	 *  Copyright: Copyright (c) 2012
	 *  @author:   
	 *  @version 1.0 2012-09-14
	 */
	private static final long serialVersionUID = 2894544204585860934L;

	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();
		
		//  Url  id
		String id = request.getParameter("id");
		
		//  ”   “   
		Map map = DB.getAll();
		//  id       
		MyObject myobj = (MyObject) map.get(id);
		
		out.write("       ："+myobj.getName()+"
");
		out.write("  ："+myobj.getPrice()+"
");
		out.write("        ：
");
		out.write(myobj.getDescribe());
		
		//      cookie
		String cookieValue = buildCookie(id, request);//     cookie   
		Cookie cookie = new Cookie("historyCookie", cookieValue);
		cookie.setMaxAge(1*24*3600);
		cookie.setPath("/myweb");
		response.addCookie(cookie);
	}

	private String buildCookie(String id, HttpServletRequest request) {
		
		String historyCookie = null;
		
		//        cookie 
		Cookie[] cookies = request.getCookies();
		for (int i = 0; cookies != null && i < cookies.length; i++){
			if (cookies[i].getName().equals("historyCookie") ){
				historyCookie = cookies[i].getValue();
			}
		}
		
		//           id
		if (historyCookie == null){
			return id;
		}
		
		LinkedList list = new LinkedList( Arrays.asList((historyCookie.split("\\,"))));
		
		//            id  
		if (list.contains(id)){
			list.remove(id);
		}else{
			if (list.size() >= 5){
				list.removeLast();
			}
		}
		list.addFirst(id);
		
		StringBuffer sb = new StringBuffer();
		for (String sid : list){
			sb.append(sid + ",");
		}
		sb.deleteCharAt(sb.length()-1);
		
		return sb.toString();
	}

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

		doGet(request, response);
	}
}

初めて商品を閲覧してクッキーを生成
表示履歴ブラウズの更新
次の商品を閲覧する
表示の更新
最初に閲覧した商品を再閲覧して前に移動します
複数の商品を閲覧する