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 circleLength() { return 2.0*Math.PI*radius; }}<%@ page language="java" contentType="text/html; charset=utf-8" pageEncoding="utf-8"%> <html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"><title>Insert title here</title></head><body><jsp:useBean id="haha" class="first.Circle" scope="page" /><%haha.setRadius(100);%><P>圆的半径是：<%=haha.getRadius()%><P>圆的周长是：<%=haha.circleLength()%><P>圆的面积是：<%=haha.circleArea()%></body></html>
scope改为qppliaction试试
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