大话设计模式--计算器

时间 2019-12-05

标签大话设计模式计算器繁體版

原文原文链接

做为一名程序员，必要的总结是不能够缺乏的。计划从如今开始到明年年末将《大话设计模式》这本书中所列举的设计模式都纪录一遍用于之后工做的提高！javascript

简单工厂之计算器css

写这个功能以前，我须要整理一下写代码的基本思路：写程序必需要以能复用，易于维护为原则，必定要使用面向对象的三大特征封装继承和多态。引用《大话设计模式》中的一个例子在活字印刷出来以前，印刷的模板都是一次性使用的，所以一本书的成本过高，这样大规模使用是很难实现的。若是放到当今这个以流量为王的时代绝对会被淘汰。代码java

public class Operation程序员
```
{
```
```
private double _numbA = 0;
```
```
private double _numbB = 0;
```
```
public double _NumbA
```
```
{
```
```
get
```
```
{
```
```
return _numbA;
```
```
}
```
```
set
```
```
{
```
```
_numbA = value;
```
```
}
```
```
}
```
```
public double _NumbB
```
```
{
```
```
get
```
```
{
```
```
return _numbB;
```
```
}
```
```
set
```
```
{
```
```
_numbB = value;
```
```
}
```
```
}
```
```
public virtual double getResult()
```
```
{
```
```
double result = 0;
```
```
return result;
```
```
}
```
```
}
```

//上边是抽象出来其余运算类须要继承的父类。web

//下边写具体实现
//加法类ajax

public class OperationAdd : Operation
```
{
```
```
public override double getResult()
```
```
{
```
```
double result = 0;
```
```
result = _NumbA + _NumbB;
```
```
return result;
```
```
}
```
```
}
```

//减法类算法

public class OperationSub : Operation
```
{
```
```
public override double getResult()
```
```
{
```
```
double result = 0;
```
```
result = _NumbA - _NumbB;
```
```
return result;
```
```
}
```
```
}
```

//乘法类express

public class OperationMulti : Operation
```
{
```
```
public override double getResult()
```
```
{
```
```
double result = 0;
```
```
result = _NumbA * _NumbB;
```
```
return result;
```
```
}
```
```
}
```

//除法类设计模式

public class OperationDivde : Operation
```
{
```
```
public override double getResult()
```
```
{
```
```
double result = 0;
```
```
if (_NumbB == 0)
```
```
{
```

throw new Exception("除数不能为零！！");

```
}
```
```
result = _NumbA / _NumbB;
```
```
return result;
```
```
}
```
```
}
```

//后台类已经写好了，前台控制台程序也好，webform程序也好均可以使用。我是以asp.net webform配合ajax来实现的。 //前台数据经过ajax传递到后台通常处理性程序(ashx)文件，数据处理后将数据传递到前台。 //在这里须要添加一个ashx类的父类，经过反射的方式简化调用程序。asp.net

//Parent.ashx中代码

public class Parent : IHttpHandler
```
{
```
```
private string m_flag;
```
```
public string Flag
```
```
{
```
```
get { return m_flag; }
```
```
set { m_flag = value; }
```
```
}
```

public void ProcessRequest(HttpContext context)

```
{
```
```
if (context.Request["flag"] != null)
```

m_flag = context.Request["flag"].ToString();

var methodName = context.Request["flag"];

```
Type objType = this.GetType();
```

MethodInfo method = objType.GetMethod(methodName == null ? "" : methodName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);

```
if (method != null)
```
```
{
```

HttpContext[] objParams = new HttpContext[] { context };

```
method.Invoke(this, objParams);
```
```
}
```
```
else
```
```
{
```
```
Other(context);
```
```
}
```
```
}
```

public virtual void Other(HttpContext context)

```
{
```
```
}
```
```
public bool IsReusable
```
```
{
```
```
get
```
```
{
```
```
return false;
```
```
}
```
```
}
```
```
}
```

//建立调用类，调用类中的代码

public class Caculate : Parent
```
{
```

public void NumOperate(HttpContext context)

```
{
```

var expression = context.Request["expression"];//这里是将用户的表达式获取过来

var operateFlag = context.Request["operateFlag"].ToCharArray();

var ExpreArry = expression.Split(operateFlag);//而后经过用户输入的运算符来分割

```
Operation operate = null;
```
```
switch (operateFlag[0])
```
```
{
```
```
case '+':
```
```
operate = new OperationAdd();
```
```
break;
```
```
case '-':
```
```
operate = new OperationSub();
```
```
break;
```
```
case '*':
```
```
operate = new OperationMulti();
```
```
break;
```
```
case '/':
```
```
operate = new OperationDivde();
```
```
break;
```
```
}
```

operate._NumbA = Convert.ToDouble(ExpreArry[0]);//不管是加减乘除均可以使用同一种方式来调用

operate._NumbB = Convert.ToDouble(ExpreArry[1]);

```
var result = operate.getResult();
```
```
context.Response.Write(result);
```
```
context.Response.End();
```
```
}
```
```
}
```

//后台调用完毕，下边开始写前台调用方式。首先须要引用jQuery文件，而后就可使用jQuery中的方法了。在这里不展现引用(太简单)

//前台HTML布局使用的是table布局

<body>
```
<table id="caclator">
```
```
<tr>
```
```
<td colspan="5">
```

<input type="text" id="txtExpression" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="MC" id="btnMC" />

```
</td>
```
```
<td>
```

<input type="button" value="MR" id="btnMR" />

```
</td>
```
```
<td>
```

<input type="button" value="MS" id="btnMS" />

```
</td>
```
```
<td>
```

<input type="button" value="M+" id="btnMAdd" />

```
</td>
```
```
<td>
```

<input type="button" value="M-" id="btnMSub" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="←" id="btnBackSpace" />

```
</td>
```
```
<td>
```

<input type="button" value="CE" id="btnCE" />

```
</td>
```
```
<td>
```

<input type="button" value="C" id="btnC" />

```
</td>
```
```
<td>
```

<input type="button" value="±" id="Button4" />

```
</td>
```
```
<td>
```

<input type="button" value="√" id="Button5" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="7" id="btnNumSeven" />

```
</td>
```
```
<td>
```

<input type="button" value="8" id="btnNumEight" />

```
</td>
```
```
<td>
```

<input type="button" value="9" id="btnNumNine" />

```
</td>
```
```
<td>
```

<input type="button" value="/" id="btnOperDivide" />

```
</td>
```
```
<td>
```

<input type="button" value="%" id="Button10" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="4" id="btnNumFour" />

```
</td>
```
```
<td>
```

<input type="button" value="5" id="btnNumFive" />

```
</td>
```
```
<td>
```

<input type="button" value="6" id="btnNumSix" />

```
</td>
```
```
<td>
```

<input type="button" value="*" id="btnOperMulti" />

```
</td>
```
```
<td>
```

<input type="button" value="1/x" id="Button12" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td>
```

<input type="button" value="1" id="btnNumOne" />

```
</td>
```
```
<td>
```

<input type="button" value="2" id="btnNumTwo" />

```
</td>
```
```
<td>
```

<input type="button" value="3" id="btnNumThree" />

```
</td>
```
```
<td>
```

<input type="button" value="-" id="btnOperSub" />

```
</td>
```
```
<td rowspan="2">
```

<input type="button" value="=" id="btnEques" />

```
</td>
```
```
</tr>
```
```
<tr>
```
```
<td colspan="2">
```

<input type="button" value="0" id="btnNumZero" />

```
</td>
```
```
<td>
```

<input type="button" value="." id="btnPoint" />

```
</td>
```
```
<td>
```

<input type="button" value="+" id="btnOperAdd" />

```
</td>
```
```
</tr>
```
```
</table>
```
</body>

//仅仅实现了+-*/最基本的算法，所以没有涉及到的按钮id名称就没修改
//如下是css样式设置

<style type="text/css">
```
input[type='button']
```
```
{
```
```
height: 25px;
```
```
width: 35px;
```
```
}
```
```
input[type='button'][value='0']
```
```
{
```
```
height: 25px;
```
```
width: 72px;
```
```
}
```
```
input[type='button'][value='=']
```
```
{
```
```
height: 52px;
```
```
width: 35px;
```
```
}
```
```
input[type='text']
```
```
{
```
```
width: 185px;
```
```
}
```
```
</style>
```

//运行图仿照win7中计算器样式

//最后添加jQuery代码

<script type="text/javascript">

var expression = ""; //存放用户表达式

var operateFlag = ""; //存放用户操做 +-*/

```
$(function () {
```
```
$("#txtExpression").val('');
```

$("#caclator").offset({ top: 300, left: 900 });

```
$.each($("input"), function (i, j) {
```
```
if (j.id.indexOf("Num") > -1) {
```
```
$("#" + j.id).click(function () {
```
```
expression += this.value;
```
```
$("#txtExpression").val(expression);
```
```
})
```
```
}
```
```
})
```
```
$.each($("input"), function (i, j) {
```
```
if (j.id.indexOf("Oper") > -1) {
```
```
$("#" + j.id).click(function () {
```
```
expression += this.value;
```
```
$("#txtExpression").val(expression);
```
```
if (this.value != ".") {
```
```
operateFlag = "";
```
```
operateFlag = this.value;
```
```
}
```
```
})
```
```
}
```
```
})
```
```
$("#btnEques").click(function () {
```

var url = "/Handler/Caculate.ashx?t=" + new Date();

```
$.ajax({
```
```
type: "POST",
```
```
url: url,
```

data: { flag: "NumOperate", expression: expression, operateFlag: operateFlag },

```
async: false,
```
```
cache: false,
```
```
success: function (msg) {
```
```
expression = "";
```
```
$("#txtExpression").val(msg);
```
```
},
```
```
error: function (msg) {
```
```
if (msg.status == 500) {
```

alert("错误，不容许的操做！");//若是除数为0，那么就会弹出提示信息

```
}
```
```
}
```
```
})
```
```
})
```
```
})
```
</script>