cookie实例-最近浏览记录

该程序实现显示最近的浏览记录，当点击书名链接时可查看关于该书的详细信息，返回后可在最近的浏览列表中查看浏览记录，最后点击的出现在最前面。
1.创建基本类Book存储基本数据

1: package net.csing;

2:

3: public class Book {

4:   public Book(){}

5:

6:   public Book(String id,String name, String auth, String price, String publish,

7:       String description) {

8:     super();

9:     this.id=id;

10:     this.name = name;

11:     this.auth = auth;

12:     this.price = price;

13:     this.publish = publish;

14:     this.description = description;

15:   }

16:   private String id;

17:   private String name;

18:   private String auth;

19:   private String price;

20:   private String publish;

21:   private String description;

22:

23:   public String getId() {

24:     return id;

25:   }

26:

27:   public void setId(String id) {

28:     this.id = id;

29:   }

30:   public String getName() {

31:     return name;

32:   }

33:   public void setName(String name) {

34:     this.name = name;

35:   }

36:   public String getAuth() {

37:     return auth;

38:   }

39:   public void setAuth(String auth) {

40:     this.auth = auth;

41:   }

42:   public String getPrice() {

43:     return price;

44:   }

45:   public void setPrice(String price) {

46:     this.price = price;

47:   }

48:   public String getPublish() {

49:     return publish;

50:   }

51:   public void setPublish(String publish) {

52:     this.publish = publish;

53:   }

54:   public String getDescription() {

55:     return description;

56:   }

57:   public void setDescription(String description) {

58:     this.description = description;

59:   }

60:

61:   @Override

62:   public String toString() {

63:     return "[name=" + name + ", auth=" + auth + ", price=" + price

64:         + ", publish=" + publish + ", description=" + description + "]";

65:   }

66: }

67:

2.创建BookDao类来操作Book数据并初始化要显示的book列表：

1: package net.csing;

2:

3: import java.util.LinkedHashMap;

4: import java.util.Map;

5:

6: public class BookDao {

7:   private static Map<String, Book> map=new LinkedHashMap<String, Book>();

8:   public BookDao(){};

9:   static{

10:     map.put("1", new Book("1","三国演义","99.0","朴乾","黑马出版社","一群男人纠结不清的故事...."));

11:     map.put("2", new Book("2","西游记","10.0","曹睿","传智出版社","一个和尚一个猴子一头猪和一个秃子去西天的故事..."));

12:     map.put("3", new Book("3","水浒传","2.0","奥巴马","人民教育出版社","105个男人和3个女人闯荡江湖的故事"));

13:     map.put("4", new Book("4","金瓶梅","200.0","哈利波特","科技出版社","混乱不堪的故事..."));

14:     map.put("5", new Book("5","逆行","3.0","高深","人民教育出版社","我们逆行"));

15:   }

16:   //根据id得到书；

17:   public static Book getBookById(String id){

18:     return map.get(id);

19:   }

20:   //获得所有的书的集合；

21:   public static Map<String,Book> getAllBook(){

22:     return map;

23:   }

24: }

25:

3.显示全部书籍的列表以及最近的浏览记录

1: package net.csing;

2:

3: import java.io.IOException;

4: import java.io.Writer;

5: import java.util.Iterator;

6: import java.util.Map;

7: import java.util.Map.Entry;

8: import java.util.Set;

9:

10: import javax.servlet.ServletException;

11: import javax.servlet.http.Cookie;

12: import javax.servlet.http.HttpServlet;

13: import javax.servlet.http.HttpServletRequest;

14: import javax.servlet.http.HttpServletResponse;

15:

16: public class Index extends HttpServlet {

17:

18:   public void doGet(HttpServletRequest request, HttpServletResponse response)

19:       throws ServletException, IOException {

20:

21:     //解决中文乱码问题；

22:     response.setContentType("text/html;charset=utf-8");

23:

24:     Writer outer=response.getWriter();

25:    outer.write("本站的所有书籍如下：<br>");

26:     //从类的方法中获得所有的书，并遍历；

27:     Map<String, Book> map=BookDao.getAllBook();

28:     Set<Entry<String, Book>> set=map.entrySet();

29:     Iterator<Entry<String,Book>> iterator=set.iterator();

30:     while(iterator.hasNext()){

31:       Entry<String, Book> entry=iterator.next();

32:       //String idString=entry.getKey();

33:       Book book=entry.getValue();

34:       //将取得书以链接列表的形式打印到浏览器页面中。

35:       //在链接页面的地址中返回该链接书的id

36:       outer.write("<a href='"+request.getContextPath()+"/servlet/Info?id="+book.getId()+"'>"+book.getName()+"</a><br>");

37:     }

38:     outer.write("<hr>");

39:     //获得cookie信息，以便查看之前的浏览记录。

40:     Cookie[] cookie=request.getCookies();

41:     //设置对应的浏览记录；

42:     Cookie findCookie=null;

43:     //判断cookie是否为空。

44:     if(cookie==null){

45:       outer.write("您尚未浏览过本站的图书...");

46:     }

47:     //cookie不为空时查看是否有符合条件的浏览记录

48:     else if(cookie!=null){

49:       for(Cookie c:cookie){

50:         if("history".equals(c.getName())){

51:           findCookie=c;

52:           break;

53:         }

54:       }

55:     }

56:     //如果有浏览记录，则分拆该值得到id并获取书名。

57:     if(findCookie!=null){

58:       outer.write("您最近浏览过的书籍如下："+"<br><br>");

59:       String[] bookid=findCookie.getValue().split("-");

60:       for(String id:bookid){

61:         outer.write(BookDao.getBookById(id).getName()+"<br>");

62:       }

63:     }

64:   }

65:

66:   public void doPost(HttpServletRequest request, HttpServletResponse response)

67:      throws ServletException, IOException {

68:

69:     response.setContentType("text/html");

70:

71:   }

72:

73: }

74:

4.对于每一本书籍，显示该书的详细信息：

1: package net.csing;

2:

3: import java.io.IOException;

4: import java.io.Writer;

5:

6: import javax.servlet.ServletException;

7: import javax.servlet.http.Cookie;

8: import javax.servlet.http.HttpServlet;

9: import javax.servlet.http.HttpServletRequest;

10: import javax.servlet.http.HttpServletResponse;

11:

12: public class Info extends HttpServlet {

13:

14:   public void doGet(HttpServletRequest request, HttpServletResponse response)

15:       throws ServletException, IOException {

16:

17:     response.setContentType("text/html;charset=utf-8");

18:     Writer outer=response.getWriter();

19:

20:     //根据请求信息中的id获得请求的书名id

21:     String idString=request.getParameter("id");

22:     //打印书信息；

23:     outer.write(BookDao.getBookById(idString).toString()+"<a href='"+request.getContextPath()+"/servlet/Index"+"'>返回</a>");

24:     //获得所有的cookie

25:    Cookie[] cookies=request.getCookies();

26:     Cookie findCookie=null;

27:     //创建stringbuffered存储临时的id字段串；

28:     StringBuffer idBuffer=new StringBuffer();

29:     //只有当cookie不为空时的判断才有意义。

30:     if(cookies!=null){

31:       //遍历并查找对应的cookie浏览记录。

32:       for(Cookie c:cookies){

33:         if("history".equals(c.getName())){

34:           findCookie=c;

35:           break;

36:         }

37:       }

38:     }

39:     //不管cookies是否为空，我们都需要判断是否查找到对应的浏览历史cookie。

40:     if(findCookie==null){

41:       idBuffer.append(idString);

42:     }

43:     else{

44:       String[] find=findCookie.getValue().split("-");

45:       //将最近的书的id放在stringbuffered的最前面，现存的依次添加到后面，这个方法简直太棒了。

46:       idBuffer.append(idString);

47:       //依次将现存的id添加到buffered中，并且限制了id的长度。

48:       for(int x=0;(x<find.length)&&(idBuffer.toString().split("-").length<3);x++){

49:         //之前浏览的id值和当前浏览的值不相同时才添加。

50:         if(!idString.equals(find[x])){

51:           idBuffer.append("-"+find[x]);

52:         }

53:       }

54:     }

55:     //将获取的id浏览记录字段串添加到对应的cookie中。

56:     Cookie cookie=new Cookie("history", idBuffer.toString());

57:     //设置cookie存活时间以及存储路径。

58:     cookie.setMaxAge(Integer.MAX_VALUE);

59:     cookie.setPath(request.getContextPath());

60:     //将获取好的cookie存储到客户端浏览器中。

61:     response.addCookie(cookie);

62:   }

63:

64:   public void doPost(HttpServletRequest request, HttpServletResponse response)

65:       throws ServletException, IOException {

66:

67:    response.setContentType("text/html");

68:

69:   }

70:

71: }

72:

5.最终效果图如下：

刚打开时的界面：





浏览后的界面：