Java中基于Scanner 编写的计算器小程序

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package com.softeem.oc;import java.util.Scanner;import java.util.regex.Matcher;import java.util.regex.Pattern;class Calculator {    private Double num1;    private Double num2;    private String var;    private  Scanner input;        public Double getNum1() {        return num1;    }    public void setNum1(Double num1) {        this.num1 = num1;    }    public Double getNum2() {        return num2;    }    public void setNum2(Double num2) {        this.num2 = num2;    }    public String getVar() {        return var;    }    public void setVar(String var) {        this.var = var;    }    public Scanner getInput() {        return input;    }    public void setInput(Scanner input) {        this.input = input;    }    public boolean input1(){            System.out.println("请输入第一个数字");            String num1Str = input.next();            if(!this.isNumber(num1Str)){                input1();            }else{                this.num1 =Double.valueOf(num1Str);            }            return true;                }    public boolean input2(){        System.out.println("输入第二个数:");        String num2Str = input.next();        if(!this.isNumber(num2Str)){            input2();        }else if(var.equalsIgnoreCase("/")&&num2Str.equalsIgnoreCase("0")){            System.err.println("除数不能为0");            input2();        }else{            this.num2 =Double.valueOf(num2Str);        }        return true;    }    public boolean inputVar(){        System.out.println("输入计算符号:+ - * /");        String varStr=input.next();         Pattern pat=Pattern.compile("[+-\\\\*/]");         Matcher match=pat.matcher(varStr);         boolean flag=match.matches();         if(flag==false){             System.err.println("运算符号不正确！");             inputVar();         }else{             this.setVar(varStr);         }                 return true;    }        public void goCal(){                Scanner input= new Scanner(System.in);        this.setInput(input);        boolean flag1=this.input1();        if(flag1){            if(this.inputVar()){                if(this.input2()){                    calculate();                }            }        }    }    public void calculate(){        try {            switch (var) {            case "+":                System.out.println(num1+"+"+num2+"="+(num1+num2));                break;            case "-":                 System.out.println(num1+"-"+num2+"="+(num1-num2));                break;            case "*":                 System.out.println(num1+"-"+num2+"="+(num1*num2));                break;            case "/":                System.out.println(num1+"/"+num2+"="+(num1/(double)num2));                break;            default:                break;            }        } catch (Exception e) {            // TODO Auto-generated catch block            e.printStackTrace();            if(input!=null){                input.close();                System.exit(0);            }        }        if(input!=null){            input.close();            System.exit(0);        }           }    public boolean isNumber(Object obj){        if(obj==null||obj.toString().equals("")){            return false;        }        Pattern pattern=Pattern.compile("[0-9]+.*[0-9]*");        String str=obj.toString();        Matcher matcher=pattern.matcher(str);        boolean flag=matcher.matches();        if(flag==false){            System.err.println("请输入有效数值！");        }        return flag;    }}public class Calc {        public static void main(String[] args) {        Calculator cal = new Calculator();        cal.goCal();                    }}
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