📄 第6章（1）.txt
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</HTML>
三角形beans
Triangle.java：
public class Triangle
{ double sideA,sideB,sideC;
double area;
boolean triangle;
public void setSideA(double a)
{sideA=a;
}
public double getSideA()
{return sideA;
}
public void setSideB(double b)
{sideB=b;
}
public double getSideB()
{return sideB;
}
public void setSideC(double c)
{sideC=c;
}
public double getSideC()
{return sideC;
}
public double getArea()
{ double p=(sideA+sideB+sideC)/2.0;
area=Math.sqrt(p*(p-sideA)*(p-sideB)*(p-sideC));
return area;
}
public boolean isTriangle()
{ if(sideA<sideB+sideC&&sideB<sideA+sideC&&sideC<sideA+sideB)
triangle=true;
else
triangle=false;
return triangle;
}
}
使用三角形beans的JSP页面(效果如图6.17所示)
triangle.jsp：
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Triangle"%>
<HTML>
<BODY ><Font size=1>
<FORM action="" Method="post" >
<P>输入三角形的边A:
<Input type=text name="sideA" value=0>
<P>输入三角形的边B:
<Input type=text name="sideB" value=0>
<P>输入三角形的边C:
<Input type=text name="sideC" value=0>
<Input type=submit value="提交">
<P>你给出三角形的三边是：
<jsp:useBean id="triangle" class="Triangle" scope="page" >
</jsp:useBean>
<jsp:setProperty name= "triangle" property="*" />
<BR>边A是：
<jsp:getProperty name= "triangle" property="sideA" />
<BR>边B是：
<jsp:getProperty name= "triangle" property="sideB" />
<BR>边C是：
<jsp:getProperty name= "triangle" property="sideC" />
<P>这三个边能构成一个三角形吗？
<jsp:getProperty name= "triangle" property="triangle" />
<P>面积是：
<jsp:getProperty name= "triangle" property="area" />
</FONT>
</BODY>
</HTML>
Counter.java：
public class Counter
{ long count=0;
public synchronized long getCount()
{count++;
return count;
}
}
count.jsp：(效果如图6.18所示)
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Counter"%>
<HTML>
<BODY ><Font size=1>
<jsp:useBean id="people" class="Counter" scope="application" >
</jsp:useBean>
<% if(session.isNew())
{ %>
<P>您是第
<jsp:getProperty name= "people" property="count" />
位访问本站的人
<%
}
else
{ out.print("禁止通过刷新增加计数！");
}
%>
</FONT>
</BODY>
</HTML>
Car1.java：
import java.util.*;
import java.io.*;
public class Car1 implements Serializable
{ Hashtable list=new Hashtable();
String item="Welcome!";
int mount=0;
String unit=null;
public void Car1()
{ }
public void setItem(String newItem)
{ item=newItem;
}
public void setUnit(String newUnit)
{ unit=newUnit;
}
public void setMount(int m)
{ mount=m;
}
public void 添加商品到购物车()
{ String str="Name: "+item+" Mount:"+mount+" Unit:"+unit;
list.put(item,str);
}
public Hashtable 列出购物车中的商品()
{ return list;
}
public void 删除货物(String s)
{ list.remove(s);
}
}
选择物品页面(效果如图6.19所示)
car.jsp：
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="java.util.*" %>
<%@ page import="Car1" %>
<HTML>
<BODY ><Font size=1>
<jsp:useBean id="car1" class="Car1" scope="session" >
</jsp:useBean>
<P>这里是第一百货商场，选择您要购买的商品添加到购物车：
<% String str=response.encodeRedirectURL("add.jsp");
%>
<FORM action="<%=str%>" method=post name=form>
<Select name="item" value="没选择">
<Option value="TV">电视机
<Option value="apple">苹果
<Option value="coke">可口可乐
<Option value="milk">牛奶
<Option value="tea">茶叶
</Select>
<P>输入购买的数量:
<Input type=text name="mount">
<P>选择计量单位：
<INPUT type="radio" name="unit" value="个">个
<INPUT type="radio" name="unit" value="公斤">公斤
<INPUT type="radio" name="unit" value="台">台
<INPUT type="radio" name="unit" value="瓶">瓶
<Input type=submit value="提交添加">
</FORM>
<P>您的购物车有如下商品：
<% Hashtable list=car1.列出购物车中的商品();
Enumeration enum=list.elements();
while(enum.hasMoreElements())
{ String goods=(String)enum.nextElement();
byte b[]=goods.getBytes("ISO-8859-1");
goods=new String(b);
out.print("<BR>"+goods);
}
%>
<% String str1=response.encodeRedirectURL("selectRemovedGoods.jsp");
%>
<FORM action="<%=str1%>" method=post name=form>
<Input type=submit value="修改购物车中的货物">
</FORM>
</FONT>
</BODY>
</HTML>
添加货物到购物车页面(效果如图6.20所示)
add.jsp：
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="java.util.*" %>
<%@ page import="Car1" %>
<HTML>
<BODY ><Font size=2>
<jsp:useBean id="car1" class="Car1" scope="session" >
</jsp:useBean>
<jsp:setProperty name= "car1" property="*" />
<% car1.添加商品到购物车();
%>
<P>您的购物车有如下商品：
<% Hashtable list=car1.列出购物车中的商品();
Enumeration enum=list.elements();
while(enum.hasMoreElements())
{ String goods=(String)enum.nextElement();
byte b[]=goods.getBytes("ISO-8859-1");
goods=new String(b);
out.print("<BR>"+goods);
}
%>
<% String str=response.encodeRedirectURL("car.jsp");
%>
<BR><FORM action="<%=str%>" method=post name=form>
<Input type=submit value="继续购物">
</FORM>
<% String str1=response.encodeRedirectURL("selectRemovedGoods.jsp");
%>
<BR><FORM action="<%=str1%>" method=post name=form>
<Input type=submit value="修改购物车中的货物">
</FORM>
</FONT>
</BODY>
</HTML>
选择删除货物的页面(效果如图6.21所示)
selectRemovedGoods.jsp：
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="java.util.*" %>
<%@ page import="Car1" %>
<HTML>
<BODY ><Font size=1>
<jsp:useBean id="car1" class="Car1" scope="session" >
</jsp:useBean>
<P>选择从购物车删除的商品：
<% String str=response.encodeRedirectURL("removeWork.jsp");
%>
<FORM action="<%=str%>" method=post name=form2>
<Select name="deleteitem" size=1>
<Option value="TV">电视机
<Option value="apple">苹果
<Option value="coke">可口可乐
<Option value="milk">牛奶
<Option value="tea">茶叶
</Select>
<Input type=submit value="提交删除">
</FORM>
<P> 您的购物车有如下商品:
<% Hashtable list=car1.列出购物车中的商品();
Enumeration enum=list.elements();
while(enum.hasMoreElements())
{ String goods=(String)enum.nextElement();
byte b[]=goods.getBytes("ISO-8859-1");
goods=new String(b);
out.print("<BR>"+goods);
}
%>
<% String str1=response.encodeRedirectURL("car.jsp");
%>
<FORM action="<%=str1%>" method=post name=form>
<Input type=submit value="继续购物">
</FORM>
</FONT>
</BODY>
</HTML>
删除货物页面(效果如图6.22所示)
removeWork.jsp：
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="java.util.*" %>
<%@ page import="Car1" %>
<HTML>
<BODY ><Font size=1>
<jsp:useBean id="car1" class="Car1" scope="session" >
</jsp:useBean>
<% String name=request.getParameter("deleteitem");
if(name==null)
{name="";
}
byte c[]=name.getBytes("ISO-8859-1");
name=new String(c);
car1.删除货物(name);
out.print("您删除了货物："+name);
%>
<P>购物车中现在的货物：
<% Hashtable list=car1.列出购物车中的商品();
Enumeration enum=list.elements();
while(enum.hasMoreElements())
{ String goods=(String)enum.nextElement();
byte b[]=goods.getBytes("ISO-8859-1");
goods=new String(b);
out.print("<BR>"+goods);
}
%>
<% String str1=response.encodeRedirectURL("car.jsp");
%>
<FORM action="<%=str1%>" method=post name=form>
<Input type=submit value="继续购物">
</FORM>
<% String str=response.encodeRedirectURL("selectRemovedGoods.jsp");
%>
<FORM action="<%=str%>" method=post name=form1>
<Input type=submit value="修改购物车中的货物">
</FORM>
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