J2EE三层框架基础.docx
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J2EE三层框架基础
一、搞清楚做什么？
（需求分析）
二、采用三层架构和MVC
三、编码
1、搭建开发环境
把需要的jar包导入
jstl.jar
standard.jar
junit.jar（Eclipse自带）
2、建立类存放的包
com.itheima.domain
com.itheima.dao
com.itheima.dao.impl
com.itheima.service
com.itheima.service.impl
com.itheima.web.controler
com.itheima.util
com.itheima.test
为了安全起见，jsp可以放在WEB-INF中的某一目录中pagesjsps
3、
Webroot
<%@pagelanguage="java"import="java.util.*"pageEncoding="ISO-8859-1"%>
<%
Stringpath=request.getContextPath（）;
StringbasePath=request.getScheme（）+":
//"+request.getServerName（）+":
"+request.getServerPort（）+path+"/";
%>
DOCTYPEHTMLPUBLIC"-//W3C//DTDHTML4.01Transitional//EN">
">
MyJSP'index.jsp'startingpage
--
-->
ThisismyJSPpage.
Src
Dao
1
packagecom.itheima.dao;
importjava.util.Map;
importcom.itheima.domain.Book;
publicinterfaceBookDao{
/**
*获取所有的书
*@returnMap<书的ID，书对象>
*/
MapfindAllBooks（）;
/**
*根据书的ID获取书对象
*@parambookid
*@return
*/
BookfindBookById（Stringbookid）;
}
2
packagecom.itheima.dao.impl;
importjava.util.Map;
importcom.itheima.dao.BookDao;
importcom.itheima.domain.Book;
importcom.itheima.util.BookDb;
publicclassBookDaoImplimplementsBookDao{
/**
*获取所有的书
*@returnMap<书的ID，书对象>
*/
publicMapfindAllBooks（）{
returnBookDb.getAll（）;
}
/**
*根据书的ID获取书对象
*@parambookid
*@return
*/
publicBookfindBookById（Stringbookid）{
returnBookDb.getBookById（bookid）;
}
}
Domain
1
packagecom.itheima.domain;
publicclassBook{
privateStringid;
privateStringname;
privateStringauthor;
privatedoubleprice;//单价
privateStringdescription;
publicBook（）{}
publicBook（Stringid,Stringname,Stringauthor,doubleprice,
Stringdescription）{
super（）;
this.id=id;
this.name=name;
this.author=author;
this.price=price;
this.description=description;
}
publicStringgetId（）{
returnid;
}
publicvoidsetId（Stringid）{
this.id=id;
}
publicStringgetName（）{
returnname;
}
publicvoidsetName（Stringname）{
this.name=name;
}
publicStringgetAuthor（）{
returnauthor;
}
publicvoidsetAuthor（Stringauthor）{
this.author=author;
}
publicdoublegetPrice（）{
returnprice;
}
publicvoidsetPrice（doubleprice）{
this.price=price;
}
publicStringgetDescription（）{
returndescription;
}
publicvoidsetDescription（Stringdescription）{
this.description=description;
}
}
2
packagecom.itheima.domain;
importjava.util.LinkedHashMap;
importjava.util.Map;
//购物车
publicclassCart{
privateintnum;//总数量
privatedoubleprice;//总价
//mapkey=bookidvalue=cartitem
privateMapmap=newLinkedHashMap（）;
publicdoublegetPrice（）{
price=0;
for（Map.Entryme:
map.entrySet（））{
CartItemitem=me.getValue（）;
price+=item.getPrice（）;
}
returnprice;
}
publicintgetNum（）{
num=0;
for（Map.Entryme:
map.entrySet（））{
CartItemitem=me.getValue（）;
num+=item.getNum（）;
}
returnnum;
}
publicMapgetMap（）{
returnmap;
}
publicvoidsetMap（Mapmap）{
this.map=map;
}
//向购物车中放书
publicvoidaddBook（Bookbook）{
//首先判断该书有没有对应的购物项
Stringbookid=book.getId（）;
booleanhas=map.containsKey（bookid）;
//有：
购物向的数量加1
if（has）{
CartItemitem=map.get（bookid）;
item.setNum（item.getNum（）+1）;
}else{
//没有：
创建一个购物项，把书放入
CartItemitem=newCartItem（）;
item.setBook（book）;
item.setNum
（1）;
map.put（bookid,item）;
}
}
publicvoiddeleteCartItem（Stringbookid）{
map.remove（bookid）;
}
}
3
packagecom.itheima.domain;
publicclassCartItem{
privateBookbook;
privateintnum;//买了几本同类型的书
privatedoubleprice;//同类型的书的总价
publicBookgetBook（）{
returnbook;
}
publicvoidsetBook（Bookbook）{
this.book=book;
}
publicintgetNum（）{
returnnum;
}
publicvoidsetNum（intnum）{
this.num=num;
}
//计算同类型的书的总价
publicdoublegetPrice（）{
returnbook.getPrice（）*num;
}
}
4
packagecom.itheima.domain;
publicclassMyConstant{
publicstaticfinalStringSHOPPING_CART="shopcart";
}
Service
packagecom.itheima.service;
importjava.util.Map;
importcom.itheima.domain.Book;
publicinterfaceBookService{
MapfindAllBooks（）;
BookfindBookById（Stringbookid）;
}
2
packagecom.itheima.service.impl;
importjava.util.Map;
importcom.itheima.dao.BookDao;
importcom.itheima.dao.impl.BookDaoImpl;
importcom.itheima.domain.Book;
importcom.itheima.service.BookService;
publicclassBookServiceImpleimplementsBookService{
BookDaodao=newBookDaoImpl（）;
publicMapfindAllBooks（）{
returndao.findAllBooks（）;
}
publicBookfindBookById（Stringbookid）{
returndao.findBookById（bookid）;
}
}
Test
packagecom.itheima.test;
importjava.util.ArrayList;
importjava.util.List;
importcom.itheima.domain.Book;
publicclassDemo1{
publicstaticvoidmain（String[]args）{
Listlist=newArrayList（）;
list.add（newBook（"1","a","b",1,"c"））;
Bookb=list.get（0）;
b.setId（"2"）;
for（Bookbb:
list）{
System.out.println（bb.getId（））;
}
}
}
Utils
packagecom.itheima.util;
importjava.util.LinkedHashMap;
importjava.util.Map;
importcom.itheima.domain.Book;
publicclassBookDb{
//Map<书的ID，书对象>
privatestaticMapbooks=newLinkedHashMap（）;
static{
books.put（"ISBN-001",newBook（"ISBN-001","JavaWeb开发","杨玉揆",10,"一本特别好的书"））;
books.put（"ISBN-002",newBook（"ISBN-002","安卓入门","卢启龙",11,"一本一般好的书"））;
books.put（"ISBN-003",newBook（"ISBN-003","JavaScript","王昭珽",38,"一本特别好的书"））;
books.put（"ISBN-004",newBook（"ISBN-004","Spring","方立勋",30,"一本很有用的书"））;
books.put（"ISBN-005",newBook（"ISBN-005","Strut2","王昭珽",58,"一本特别好的书"））;
books.put（"ISBN-006",newBook（"ISBN-006","Hibernate","张孝祥",68,"一本超经典的书"））;
}
publicstaticMapgetAll（）{
returnbooks;
}
publicstaticBookgetBookById（Stringbookid）{
returnbooks.get（bookid）;
}
}
Web
1
packagecom.itheima.web.controler;
importjava.io.IOException;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importjavax.servlet.http.HttpSession;
importcom.itheima.domain.Book;
importcom.itheima.domain.Cart;
importcom.itheima.domain.MyConstant;
importcom.itheima.service.BookService;
importcom.itheima.service.impl.BookServiceImple;
publicclassBuyServletextendsHttpServlet{
privateBookServiceservice=newBookServiceImple（）;
publicvoiddoGet（HttpServletRequestrequest,HttpServletResponseresponse）
throwsServletException,IOException{
Stringbookid=request.getParameter（"bookid"）;
//获取购物车
HttpSessionsession=request.getSession（）;
Cartcart=（Cart）session.getAttribute（MyConstant.SHOPPING_CART）;
Bookbook=service.findBookById（bookid）;
//没有购物车，创建一个，并放入session中
if（cart==null）{
cart=newCart（）;
cart.addBook（book）;
session.setAttribute（MyConstant.SHOPPING_CART,cart）;
}else{
//有，直接将内容添加到购物车
cart.addBook（book）;
}
//转向购物车列表
request.getRequestDispatcher（"/WEB-INF/pages/listCart.jsp"）.forward（request,response）;
}
publicvoiddoPost（HttpServletRequestrequest,HttpServletResponseresponse）
throwsServletException,IOException{
doGet（request,response）;
}
}
2
packagecom.itheima.web.controler;
importjava.io.IOException;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importcom.itheima.domain.Cart;
importcom.itheima.domain.CartItem;
importcom.itheima.domain.MyConstant;
//修改数量
publicclassChangeNumServletextendsHttpServlet{
publicvoiddoGet（HttpServletRequestrequest,HttpServletResponseresponse）
throwsServletException,IOException{
//得到请求参数bookid和新的数量
Stringbookid=request.getParameter（"bookid"）;
Stringnum=request.getParameter（"num"）;//有可能是负数
intnewNum=0;
try{
newNum=Integer.parseInt（num）;
if（newNum<=0）
thrownewRuntimeException（）;
}catch（Exceptione）{
//用户输入错误的数值，提示用户
request.setAttribute（"message","数量请输入数字"）;
request.getRequestDispatcher（"/WEB-INF/pages/message.jsp"）.forward（request,response）;
return;
}
//得到购物车。
根据bookid获取购物项
Cartcart=（Cart）request.getSession（）.getAttribute（MyConstant.SHOPPING_CART）;
CartItemitem=cart.getMap（）.get（bookid）;
//修改购物项中的num
item.setNum（newNum）;
//转向listCart.jsp
request.getRequestDispatcher（"/WEB-INF/pages/listCart.jsp"）.forward（request,response）;
}
publicvoiddoPost（HttpServletRequestrequest,HttpServletResponseresponse）
throwsServletException,IOException{
doGet（request,response）;
}
}
3
packagecom.itheima.web.controler;
importjava.io.IOException;
importjavax.servlet.ServletException;
importjavax.servlet.http.HttpServlet;
importjavax.servlet.http.HttpServletRequest;
importjavax.servlet.http.HttpServletResponse;
importcom.itheima.domain.Cart;
importcom.itheima.domain.MyConstant;
//清空购物车
publicclassClearItemServletextendsHttpServl
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