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第6章JavaBeans与JSP
Circle.java:
import java.io.*;
public class Circle
{ int radius;
public Circle()
{ radius=1;
}
public int getRadius()
{ return radius;
}
public void setRadius(int newRadius)
{radius=newRadius;
}
public double circleArea()
{return Math.PI*radius*radius;
}
public double circlLength()
{return 2.0*Math.PI*radius;
}
}
例子1(效果如图6.2所示)
useBeans.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Circle"%>
<HTML>
<BODY bgcolor=cyan><Font size=1>
<jsp:useBean id="girl" class="Circle" scope="page" >
</jsp:useBean>
<%--通过上述JSP标签,客户获得了一个作用域是page,名字是girl的beans --%>
<% //设置圆的半径:
girl.setRadius(100);
%>
<P>圆的半径是:
<%=girl.getRadius()%>
<P>圆的周长是:
<%=girl.circlLength()%>
<P>圆的面积是:
<%=girl.circleArea()%>
</BODY>
</HTML>
例子2(效果如图6.3、6.4、6.5所示)
beans1.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Circle"%>
<HTML>
<BODY bgcolor=cyan><Font size=1>
<jsp:useBean id="girl" class="Circle" scope="session" >
</jsp:useBean>
<P>圆的半径是:
<%=girl.getRadius()%>
<A href="beans2.jsp"><BR>beans2.jsp </A>
</BODY>
</HTML>
beans2.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Circle"%>
<HTML>
<BODY bgcolor=cyan><Font size=1>
<jsp:useBean id="girl" class="Circle" scope="session" >
</jsp:useBean>
<P>圆的半径是:
<%=girl.getRadius()%>
<%girl.setRadius(400);%>
<P>修改后的圆的半径是:
<%=girl.getRadius()%>
</BODY>
</HTML>
例子3(效果如图6.6、6.7所示)
appbeans.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Circle"%>
<HTML> <BODY>
<jsp:useBean id="girl" class="Circle" scope="application" >
</jsp:useBean>
<P>圆的初始半径是:
<%=girl.getRadius()%>
<%girl.setRadius(1000);%>
<P>修改后的圆的半径是:
<%=girl.getRadius()%>
</BODY>
</HTML>
Circle2.java:
import java.io.*;
public class Circle2
{ double radius=1;
double circleArea=0;
double circleLength=0;
public double getRadius()
{ return radius;
}
public void setRadius(double newRadius)
{radius=newRadius;
}
public double getCircleArea()
{circleArea=Math.PI*radius*radius;
return circleArea;
}
public double getCircleLength()
{ circleLength=2.0*Math.PI*radius;
return circleLength;
}
}
例子4(效果如图6.10所示)
beansGetproperty.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Circle2"%>
<HTML>
<BODY bgcolor=cyan><Font size=1>
<jsp:useBean id="apple" class="Circle2" scope="page" >
</jsp:useBean>
<%apple.setRadius(100);%>
<P>圆的半径是:
<jsp:getProperty name= "apple" property= "radius" />
<P>圆的面积是:
<jsp:getProperty name= "apple" property= "circleArea" />
<P>圆的周长是:
<jsp:getProperty name= "apple" property= "circleLength" />
</BODY>
</HTML>
例子5(效果如图6.11所示)
student.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Student"%>
<HTML>
<BODY bgcolor=cyan><Font size=1>
<jsp:useBean id="zhang" class="Student" scope="page" >
</jsp:useBean>
<jsp:setProperty name= "zhang" property="name" value="张小三" />
<P>名字是:
<jsp:getProperty name= "zhang" property="name" />
<jsp:setProperty name= "zhang" property="number" value="1999001" />
<P>学号是:
<jsp:getProperty name= "zhang" property="number" />
<% double height=1.70;
%>
<jsp:setProperty name= "zhang" property="height" value="<%=height+0.05%>" />
<P>身高是:
<jsp:getProperty name= "zhang" property="height" />
米
<jsp:setProperty name= "zhang" property="weight" value="67.65" />
<P>体重是:
<jsp:getProperty name= "zhang" property="weight" />
公斤
</FONT>
</BODY>
</HTML>
例子6(效果如图6.12所示)
student2.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Student"%>
<HTML>
<BODY ><Font size=1>
<FORM action="" Method="post" >
<P>输入学生的姓名:
<Input type=text name="name">
<P>输入学生的学号:
<Input type=text name="number">
<P>输入学生的身高:
<Input type=text name="height">
<P>输入学生的体重:
<Input type=text name="weight">
<Input type=submit value="提交">
</FORM>
<jsp:useBean id="zhang" class="Student" scope="page" >
</jsp:useBean>
<jsp:setProperty name= "zhang" property="*" />
<P>名字是:
<jsp:getProperty name= "zhang" property="name" />
<P>学号是:
<jsp:getProperty name= "zhang" property="number" />
<P>身高是:
<jsp:getProperty name= "zhang" property="height" />
米
<P>体重是:
<jsp:getProperty name= "zhang" property="weight" />
公斤
</FONT>
</BODY>
</HTML>
例子7(效果如图6.13所示)
student3.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="Student"%>
<HTML>
<BODY bgcolor=yellow><Font size=1>
<FORM action="" Method="post" >
<P>输入学生的姓名:
<Input type=text name="name">
<P>输入学生的学号:
<Input type=text name="number">
<P>输入学生的身高:
<Input type=text name="height">
<P>输入学生的体重:
<Input type=text name="weight">
<BR> <Input type=submit value="提交">
</FORM>
<jsp:useBean id="zhang" class="Student" scope="page" >
</jsp:useBean>
<jsp:setProperty name= "zhang" property="name" param="name" />
<P>名字是:
<jsp:getProperty name= "zhang" property="name" />
<jsp:setProperty name= "zhang" property="number" param="number" />
<P>学号是:
<jsp:getProperty name= "zhang" property="number" />
<% double height=1.70;
%>
<jsp:setProperty name= "zhang" property="height" param="height" />
<P>身高是:
<jsp:getProperty name= "zhang" property="height" />
米
<jsp:setProperty name= "zhang" property="weight" param="weight" />
<P>体重是:
<jsp:getProperty name= "zhang" property="weight" />
公斤
</FONT>
</BODY>
</HTML>
例子8(效果如图6.14所示)
listfile.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="ListFile" %>
<HTML>
<BODY ><Font size=1>
<FORM action="" Method="post" >
<P>输入文件的扩展名:
<Input type=text name="extendsName">
<Input type=submit value="提交">
<jsp:useBean id="file" class="ListFile" scope="page" >
</jsp:useBean>
<jsp:setProperty name= "file" property="*" />
<P>当前JSP页面所在目录中,扩展名是:
<jsp:getProperty name= "file" property="extendsName" />
文件有:
<% String name[]=file.listFile();
for(int i=0;i<name.length;i++)
{out.print("<BR>"+name[i]);
}
%>
</BODY>
</HTML>
求素数的beans
PrimNumber.java:
package tom.jiafei;
public class PrimNumber
{ int number;
StringBuffer result;
public PrimNumber()
{ result=new StringBuffer();
}
public void setNumber(int n)
{ number=n;
int i,j;
for( i=2;i<=number;i++) //找出number以内的素数。
{for(j=2;j<i;j++)
{if(i%j==0)
break;
}
if(j>=i)
result.append(""+i+"<BR>");
}
}
public int getNumber()
{return number;
}
public StringBuffer getResult()
{ return result;
}
}
例子9使用求素数beans的JSP页面(效果如图6.16所示)
primnumber.jsp:
<%@ page contentType="text/html;charset=GB2312" %>
<%@ page import="tom.jiafei.*" %>
<HTML>
<BODY bgcolor=cyan><Font size=1>
<FORM action="" Method="post" >
<P>输入一个正整数:
<Input type=text name="number">
<Input type=submit value="提交">
<jsp:useBean id="prim" class="tom.jiafei.PrimNumber" scope="page" >
</jsp:useBean>
<jsp:setProperty name= "prim" property="number" param="number" />
<P>小于
<jsp:getProperty name= "prim" property="number" />
这个数的全部素数是:
<BR> <jsp:getProperty name= "prim" property="result" />
</Font>
</BODY>
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