简单的描述：一个父类、多个子类，实例化那个子类由一个单独的工厂类来进行
图片摘自大话设计模式：
运算类：
1 package com.longsheng.simpleFactory;
2
3 public class Calculate {
4
5 private double firstNum;
6 private double secondNum;
7
8 public double getFirstNum() {
9 return firstNum;
10 }
11
12 public void setFirstNum(double firstNum) {
13 this.firstNum = firstNum;
14 }
15
16 public double getSecondNum() {
17 return secondNum;
18 }
19
20 public void setSecondNum(double secondNum) {
21 this.secondNum = secondNum;
22 }
23
24 public double getResult() {
25 return 0d;
26 }
27 }
Calculate
加法类：
1 package com.longsheng.simpleFactory;
2
3 public class OperationAdd extends Calculate {
4
5 @Override
6 public double getResult() {
7 return getFirstNum() + getSecondNum();
8 }
9
10 }
OperationAdd
减法类：
1 package com.longsheng.simpleFactory;
2
3 public class OperationMinus extends Calculate {
4
5 @Override
6 public double getResult() {
7 return getFirstNum() - getSecondNum();
8 }
9
10 }
OperationMinus
乘法类：
1 package com.longsheng.simpleFactory;
2
3 public class OperationMutil extends Calculate {
4
5 @Override
6 public double getResult() {
7 return getFirstNum() * getSecondNum();
8 }
9
10 }
OperationMutil
除法类：
1 package com.longsheng.simpleFactory;
2
3 public class OperationDivide extends Calculate {
4
5 @Override
6 public double getResult() {
7 if( Math.abs(getSecondNum()) < 0.000001 ) {
8 throw new RuntimeException("除数不能为0");
9 }
10 return getFirstNum() / getSecondNum();
11 }
12
13 }
OperationDivide
简单工厂类：
1 package com.longsheng.simpleFactory;
2
3 public class OperationFactory {
4
5 public static Calculate getCalculate( String operation ) {
6 Calculate cal = null;
7 switch( operation ) {
8 case "+":
9 cal = new OperationAdd();
10 break;
11 case "-":
12 cal = new OperationMinus();
13 break;
14 case "*":
15 cal = new OperationMutil();
16 break;
17 case "/":
18 cal = new OperationDivide();
19 break;
20 }
21 return cal;
22 }
23
24 }
OperationFactory
客户端：
1 //两个数运算，输出结果
2 package com.longsheng.simpleFactory;
3
4 import java.util.Scanner;
5
6 public class Client {
7
8 public static void main(String[] args) {
9 double firstNum;
10 String oper;
11 double secondNum;
12
13 Scanner sc = new Scanner(System.in);
14
15 System.out.println("请输入第一个数字");
16 firstNum = sc.nextDouble();
17 System.out.println("请输入运算符(+、-、*、/)");
18 oper = sc.next();
19 System.out.println("请输入第二个运算符");
20 secondNum = sc.nextDouble();
21
22 Calculate cal = OperationFactory.getCalculate(oper);
23 cal.setFirstNum(firstNum);
24 cal.setSecondNum(secondNum);
25 System.out.print("运算的结果是");
26 System.out.println(cal.getResult());
27 sc.close();
28 }
29
30 }
Client
大话设计模式_简单工厂模式(Java代码),布布扣,bubuko.com
时间： 2024-08-01 22:46:05