IntelliJ IDEA 2018 配置servlet

前提配置好java web开发环境:点击

主要有俩种方法

1. .在servlet3.0以前,需要在web.xml文件中将其映射为url.
2. .在servlet3.0(即tomcat7以上),在类名上添加@webServlet("/class_name")即可.

 

我们采用mvc模式,实现俩个数字的运算.

名为inputNumber.jsp的页面提供一个表单，用户可以通过表单输入两个数和运算符号提交给Servlet控制器；

名为ComputerBean.java生成的JavaBean负责存储运算数、运算符号和运算结果，

名为handleComputer的servlet控制器负责运算，将结果存储到JavaBean中，并负责请求JSP页面lookResult.jsp显示JavaBean中的数据。

inputNumber.jsp

<%--
  Created by IntelliJ IDEA.
  User: max
  Date: 2018/10/30
  Time: 16:30
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    



    
数字1:
    
运算符:
    
数字2:
    

 ComputerBean.java

public class ComputerBean {
    private double number1;
    private double number2;
    private String CalChar;
    private double result;

    public ComputerBean() {

    }

    public ComputerBean(double number1, double number2, String calChar) {
        this.number1 = number1;
        this.number2 = number2;
        this.CalChar = calChar;
    }

    public double getNumber1() {
        return number1;
    }

    public void setNumber1(double number1) {
        this.number1 = number1;
    }

    public double getNumber2() {
        return number2;
    }

    public void setNumber2(double number2) {
        this.number2 = number2;
    }

    public String getCalChar() {
        return CalChar;
    }

    public void setCalChar(String calChar) {
        CalChar = calChar;
    }

    public double getResult() {
        switch (this.CalChar) {
            case "-":
                setResult(this.number1 - this.number2);
                break;
            case "+":
                setResult(this.number1 + this.number2);
                break;
            case "*":
                setResult(this.number1 * this.number2);
                break;
            case "/":
                setResult(this.number1 / this.number2);
                break;
        }
        return this.result;
    }

    public void setResult(double result) {
        this.result = result;
    }

    public boolean isCalchar() {
        if (this.CalChar.equals("+") || this.CalChar.equals("-") || 
            this.CalChar.equals("/") || this.CalChar.equals("*"))
            return true;
        else
            return false;
    }


}

showResult.jsp

<%--
  Created by IntelliJ IDEA.
  User: max
  Date: 2018/10/30
  Time: 17:11
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>


    


${message}

 hanleComputer.java

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

//@WebServlet(name = "/handleComputer")
public class handleComputer extends HttpServlet {

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

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        String number1 = request.getParameter("number1");
        String number2 = request.getParameter("number2");
        String calchar = request.getParameter("calchar");

        HttpSession session = request.getSession();

        if (number1 == null||number2==null){
            session.setAttribute("message","输入数字不能为空!");
            response.sendRedirect("showresult.jsp");
            return ;
        }
        if (calchar == null) calchar = "error";

        double n1 = 0;
        double n2 = 0;

        try {
            n1 = Double.parseDouble(number1);
            n2 = Double.parseDouble(number2);
            
        } catch (NumberFormatException e) {
            e.printStackTrace();
        }

        ComputerBean computerBean = new ComputerBean(n1, n2, calchar);

        

        if (computerBean.isCalchar()) {

            if (computerBean.getCalChar().equals("/") && computerBean.getNumber2() == 0)
                session.setAttribute("message", "除数不能为0!");
            else
                session.setAttribute("message", "结果为:" + computerBean.getResult());
            
        } else {
            session.setAttribute("message", "输入的字符串有误,请重新输入!");
        }
        response.sendRedirect("lookResult.jsp");
    }
}

1.修改web.xml文件的方法

    
        handleComputer
        handleComputer
    

    
        handleComputer
        /handleComputer
    

 

2.利用@webServlet(name = "类名", urlPatterns = "路径")

如图添加在类名上面

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

@WebServlet(name = "handleComputer", urlPatterns = "/handleComputer")
public class handleComputer extends HttpServlet {

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

    protected void doGet(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException {

        String number1 = request.getParameter("number1");
        String number2 = request.getParameter("number2");
        String calchar = request.getParameter("calchar");

        HttpSession session = request.getSession();

        if (number1 == null||number2==null){
            session.setAttribute("message","输入数字不能为空!");
            response.sendRedirect("showresult.jsp");
            return ;
        }
        if (calchar == null) calchar = "error";

        double n1 = 0;
        double n2 = 0;

        try {
            n1 = Double.parseDouble(number1);
            n2 = Double.parseDouble(number2);
            
        } catch (NumberFormatException e) {
            e.printStackTrace();
        }

        ComputerBean computerBean = new ComputerBean(n1, n2, calchar);

        

        if (computerBean.isCalchar()) {

            if (computerBean.getCalChar().equals("/") && computerBean.getNumber2() == 0)
                session.setAttribute("message", "除数不能为0!");
            else
                session.setAttribute("message", "结果为:" + computerBean.getResult());
            
        } else {
            session.setAttribute("message", "输入的字符串有误,请重新输入!");
        }
        response.sendRedirect("lookResult.jsp");
    }
}

 

运行结果