Java工厂设计模式(简单计算器实现)
总体的目录结构如下
1.基础工厂类
public interface BaseFactory {
}2.拓展工厂类
public class OperationFactoryimplements BaseFactory{
/**
* 工厂类的本质是帮助判断对应的实例,将这种判断放在工厂当中,那么就节省了让操作类自己来进行操作的性能判断,这是使用多态来解决父类和子类之间的差异
*
* @param operation
* @return
*/
public static Operation createOperation(String operation) {
Operation oper =null;
switch (operation) {
case "+":
oper =new OperationAddServiceImpl();
break;
case "-":
oper =new OperationSubServiceImpl();
break;
case "*":
oper =new OperationMulServiceimpl();
break;
case "/":
oper =new OperationDivServiceImpl();
break;
}
return oper;
}
}3.基础操作类
public class Operation {
protected DoublenumberA;
protected DoublenumberB;
public Double getNumberA() {
return numberA;
}
public void setNumberA(Double numberA) {
this.numberA = numberA;
}
public Double getNumberB() {
return numberB;
}
public void setNumberB(Double numberB) {
this.numberB = numberB;
}
/**
* 子类当中复写了当前方法,所以会优先使用子类的方法,这就是一种多态的用法
*
* @return
*/
public Double getResult() {
Double result =0D;
return result;
}
}4.加法Service
public interface OperationAddService {
/**
* 两个数相加
*
* @return
*/
Double getResult();
}5.除法Service
public interface OperationDivService {
/**
* 两数相除得到的结果
*
* @return
*/
Double getResult();
}6.乘法Service
public interface OperationMulService {
/**
* 两个数相乘的结果
*
* @return
*/
Double getResult();
}7.减法Service
public interface OperationSubService {
/**
* 两个数的减法
*
* @return
*/
Double getResult();
}8.加法ServiceImpl
public class OperationAddServiceImplextends Operationimplements OperationAddService {
@Override
public Double getResult() {
Double result =0D;
result =numberA +numberB ;
return result;
}
}9.除法ServiceImpl
public class OperationDivServiceImplextends Operationimplements OperationDivService {
@Override
public Double getResult() {
Double result =0D;
if (numberB ==0){
throw new LogicalException("除数不能为0");
}
result =numberA /numberB ;
return result;
}
}10.减法ServiceImpl
public class OperationSubServiceImplextends Operationimplements OperationSubService {
@Override
public Double getResult() {
Double result =0D;
result =numberA -numberB ;
return result;
}
}11.Controller层
@Controller
public class OperationController {
@Autowired
OperationServiceoperationService;
@RequestMapping("/index")
public String index(){
return "login";
}
@RequestMapping("/calculate")
public String operation(Model model, Double numberA , Double numberB , String operation){
Operation oper;
oper = OperationFactory.createOperation(operation);
oper.setNumberA(numberA);
oper.setNumberB(numberB);
model.addAttribute("result",oper.getResult());
return "login";
}
}12.使用freemarker来作为前端展示
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>页面</title>
<body>
<form action="/calculate" method="post" >
numberA:<input type="text" size="30" name="numberA"><br>
numberB:<input type="text" size="30" name="numberB"><br>
<select class="form-control" name="operation" id="state">
<option value="+">+</option>
<option value="-">-</option>
<option value="*">*</option>
<option value="/">/</option>
</select><input type="submit" value="comfirm"><br>
结果:<input type="text" value="${(result)!""}" readonly>
</form>
</body>
</html>本文参与 腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。
原始发表：2019/04/08 ，如有侵权请联系 cloudcommunity@tencent.com 删除
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