The value for the useBean class attribute tom.jiafei.Circle is invalid.

植物乳酸菌 2017-03-24 11:37:05

我的jsp文件：example4_1.jsp
<%@ page contentType="text/html;charset=GB2312" %>
<HTML><body bgcolor=cyan>
<jsp:useBean id="circle" class="tom.jiafei.Circle" scope="page" />
圆的初始半径是：<%=circle.getRadius()%>
<% double newRadius = 100;
circle.setRadius(newRadius);
%>
修改半径为<%= newRadius%>
 目前圆的半径是：<%=circle.getRadius() %>
 圆的周长是：<%= circle.circleLength() %>
 圆的面积是：<%= circle.circleArea() %>
</body></body></HTML>

javabean文件：
Circle.ava:
package tom.jiafei;
public class Circle{
double radius;
public Circle(){
radius=1;
}
public double getRadius(){
return radius;
}
public void setRadius(double newRadius){
radius=newRadius;
}
public double circleArea(){
return Math.PI*radius*radius;
}
public double circleLength(){
return 2.0*Math.PI*radius;
}
}

然后报错了，百度了很多方法还是解决不了，求大神帮助

exception

org.apache.jasper.JasperException: /ch4/example4_1.jsp (line: 3, column: 4) The value for the useBean class attribute tom.jiafei.Circle is invalid.
org.apache.jasper.compiler.DefaultErrorHandler.jspError(DefaultErrorHandler.java:41)
org.apache.jasper.compiler.ErrorDispatcher.dispatch(ErrorDispatcher.java:291)
org.apache.jasper.compiler.ErrorDispatcher.jspError(ErrorDispatcher.java:114)
org.apache.jasper.compiler.Generator$GenerateVisitor.visit(Generator.java:1379)
org.apache.jasper.compiler.Node$UseBean.accept(Node.java:1187)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2392)
org.apache.jasper.compiler.Node$Visitor.visitBody(Node.java:2444)
org.apache.jasper.compiler.Node$Visitor.visit(Node.java:2450)
org.apache.jasper.compiler.Node$Root.accept(Node.java:471)
org.apache.jasper.compiler.Node$Nodes.visit(Node.java:2392)
org.apache.jasper.compiler.Generator.generate(Generator.java:3668)
org.apache.jasper.compiler.Compiler.generateJava(Compiler.java:252)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:372)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:349)
org.apache.jasper.compiler.Compiler.compile(Compiler.java:333)
org.apache.jasper.JspCompilationContext.compile(JspCompilationContext.java:600)
org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:368)
org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:385)
org.apache.jasper.servlet.JspServlet.service(JspServlet.java:329)
javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
note The full stack trace of the root cause is available in the Apache Tomcat/8.5.11 logs.

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