JSP程序设计习题答案(张跃平、耿祥义)(5)

二次项系数：

是一元二次方程吗？方程的两个根是：

（3） 控制器

HandleData.java：

package sun.yourservlet; import moon.yourbean.*; import java.io.*; import javax.servlet.*; import javax.servlet.http.*;

public class HandleData extends HttpServlet

{ public void init(ServletConfig config) throws ServletException {super.init(config); }

public void doPost(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException { Equation equ=new Equation(); //创建Javabean对象

request.setAttribute(\将equ存储到HttpServletRequest对象中 double a=Double.parseDouble(request.getParameter(\ double b=Double.parseDouble(request.getParameter(\ double c=Double.parseDouble(request.getParameter(\ equ.setA(a); //将数据存储在equ中 equ.setB(b); equ.setC(c); if(a!=0)

equ.setIsSquareEquation(true); else

equ.setIsSquareEquation(true); double disk=b*b-4*a*c; if(disk<0)

{ equ.setRootOne(\无实根\ equ.setRootTwo(\无实根\ } else

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{ double root1=(-b+Math.sqrt(disk))/(2*a), root2=(-b-Math.sqrt(disk))/(2*a); equ.setRootOne(\ equ.setRootTwo(\ }

RequestDispatcher dispatcher=request.getRequestDispatcher(\

dispatcher.forward(request,response); //请求show.jsp显示equ中的数据 }

public void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException,IOException { doPost(request,response); } }

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