javaEE(MVC)

Posted 2023-05-08

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package mvc_Test;
public class model_Bean

private double result=0;
private double num1=0,num2=0,num3=0;

public double getNum1()
return num1;

public void setNum1(String x1)
this.num1 = Double.parseDouble("x1");

public double getNum2()
return num2;

public void setNum2(String x2)
this.num2 = Double.parseDouble("x2");

public double getNum3()
return num3;

public void setNum3(String x3)
this.num3 = Double.parseDouble("x3");

public double getTriangleArea()

double p=(num1+num2+num3)/2;
result=Math.sqrt(p*(p-num1)*(p-num2)*(p-num3));
return result;

//第一段代码，是M模型的。

//另一个文件,是C控制的。
package mvc_Test;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import mvc_Test.model_Bean;
public class controller_Servlet extends HttpServlet
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
double n1=0,n2=0,n3=0;
//String A=request.getParameter("a");
//String B=request.getParameter("b");
//String C=request.getParameter("c");
model_Bean mb=new model_Bean();
mb.setNum1("3");
mb.setNum2("4");
mb.setNum3("5");
double result=mb.getTriangleArea();

n1=mb.getNum1();
n2=mb.getNum2();
n3=mb.getNum3();
response.setContentType("text/html;charset=gb2312");
request.setAttribute("result",String.valueOf(result));
request.setAttribute("n1",String.valueOf(n1));
request.setAttribute("n2",String.valueOf(n2));
request.setAttribute("n3", String.valueOf(n3));
RequestDispatcher rd=request.getRequestDispatcher("/result.jsp");
rd.forward(request, response);

//问题：为什么我实例化模型调用模型的设置成员变量的时候总是报错，就是mb.setNum1("3");貌似报的数据类型错误，看不出来哪里错了，大神看看。

public void setNum1(String x1)
this.num1 = Double.parseDouble("x1");

"x1"不需要"" 参考技术A public void setNum1(String x1)
this.num1 = Double.parseDouble("x1"); //x1多了引号

---------->>>
public void setNum1(String x1)
this.num1 = Double.parseDouble(x1);

setNum2() setNum3() 也是同样哦