设计模式——工厂方法模式

工厂方法模式：生产那种产品不再是由参数决定，定义一个创建对象的工厂接口，让实现工厂接口的具体类决定实例化哪一个产品类，将实际创建工作推迟到子类当中。

① 一个产品接口

② 一个工厂接口

③ 实现了产品接口的具体产品类

④ 实现了工厂接口的具体工厂类

⑤ 消费者类，用于测试

例子一

角色：一个产品接口

1 package com.test.factoryMethod2;
2 
3 public interface Shape {
4     public abstract void draw();
5 }

角色：一个工厂接口

1 package com.test.factoryMethod2;
2 
3 public interface ShapeFactory {
4     public abstract Shape getShape();
5 }

角色：具体的产品类 Circle

1 package com.test.factoryMethod2;
2 
3 public class Circle implements Shape {
4     @Override
5     public void draw() {
6         System.out.println(" I am the Circle");
7     }
8 }

角色：具体的产品类 Rectangle

1 package com.test.factoryMethod2;
2 
3 public class Rectangle implements Shape {
4     @Override
5     public void draw() {
6         System.out.println("I am the Rectangle");
7     }
8 }

角色：具体的产品类 Square

1 package com.test.factoryMethod2;
2 
3 public class Square implements Shape {
4     @Override
5     public void draw() {
6         System.out.println("I am the Square");
7     }
8 }

角色：与产品类Circle对应具体的工厂类

1 package com.test.factoryMethod2;
2 
3 public class CircleFactory implements ShapeFactory {
4     @Override
5     public Shape getShape() {
6         return new Circle();
7     }
8 }

角色：与产品类Rectangle 对应具体的工厂类

1 package com.test.factoryMethod2;
2 
3 public class RectangleFactory implements ShapeFactory {
4     @Override
5     public Shape getShape() {
6         return new Rectangle();
7     }
8 }

角色：与产品类Square对应具体的工厂类

1 package com.test.factoryMethod2;
2 
3 public class SquareFactory implements ShapeFactory {
4     @Override
5     public Shape getShape() {
6         return new Square();
7     }
8 }

测试

 1 package com.test.factoryMethod2;
 2 
 3 public class FactoryMethodDemo {
 4     public static void main(String[] args){
 5         ShapeFactory circleFactory = new CircleFactory();
 6         circleFactory.getShape().draw();
 7 
 8         ShapeFactory rectangleFactory = new RectangleFactory();
 9         rectangleFactory.getShape().draw();
10 
11         ShapeFactory squareFactory = new SquareFactory();
12         squareFactory.getShape().draw();
13     }
14 }

测试结果：

例子二在产品接口和具体产品类之间增加了一个抽象类

角色：产品接口

 1 package com.test.factoryMethod;
 2 
 3 import java.util.Map;
 4 
 5 public interface MyMessage {
 6     /*
 7     * 产品接口
 8     */
 9     public abstract Map<String, Object> getMessageParam();
10     public abstract void setMessageParam(Map<String, Object> messageParam);
11     public abstract void sendMessage() throws Exception;
12 }

角色：抽象产品类实现了一些共有方法

 1 package com.test.factoryMethod;
 2 
 3 import java.util.Map;
 4 
 5 public abstract class MyAbstractMessage implements MyMessage {
 6     /*
 7     * 抽象产品类
 8     */
 9     private Map<String, Object> messageParam;
10     @Override
11     public Map<String, Object> getMessageParam(){
12         return messageParam;
13     }
14     @Override
15     public void setMessageParam(Map<String, Object> messageParam){
16         this.messageParam = messageParam;
17     }
18 }

角色：具体产品类 EmialMessage

 1 package com.test.factoryMethod;
 2 
 3 public class EmailMessage extends MyAbstractMessage {
 4     @Override
 5     public void sendMessage() throws Exception {
 6         if (null == getMessageParam() || null == getMessageParam().get("EMAIL") || "".equals(getMessageParam().get("EMAIL"))){
 7             throw new Exception("发送短信，需要传入EMAIL参数");
 8         }
 9         System.out.println("我是邮件，发送通知给" + getMessageParam().get("EMAIL"));
10     }
11 }

角色：具体产品类 OAMessage

 1 package com.test.factoryMethod;
 2 
 3 public class OAMessage extends MyAbstractMessage {
 4     @Override
 5     public void sendMessage() throws Exception {
 6         if (null == getMessageParam() || null == getMessageParam().get("OA_userName") || "".equals(getMessageParam().get("OA_userName"))){
 7             throw new Exception("发送OA待办，需要传入 OA_userName 参数");
 8         }
 9         System.out.println("我是OA待办，发送通知给" + getMessageParam().get("OA_userName"));
10     }
11 }

角色：具体产品类 SMSMessage

 1 package com.test.factoryMethod;
 2 
 3 public class SMSMessage extends MyAbstractMessage {
 4     @Override
 5     public void sendMessage() throws Exception {
 6         if (null == getMessageParam() || null == getMessageParam().get("phone_number") || "".equals(getMessageParam().get("phone_number"))){
 7             throw new Exception("发送短信，需要传入phone_number参数");
 8         }
 9         System.out.println("我是短信，发送通知给" + getMessageParam().get("phone_number"));
10     }
11 }

角色：工厂接口

1 package com.test.factoryMethod;
2 
3 public interface FactoryMethod {
4     /*
5     * 工厂接口
6     */
7     public abstract MyMessage createMessage(String messageType);
8 }

角色：具体工厂类

 1 package com.test.factoryMethod;
 2 
 3 import java.util.HashMap;
 4 import java.util.Map;
 5 
 6 public class FactoryMethod1 implements FactoryMethod {
 7     @Override
 8     public MyMessage createMessage(String messageType) {
 9         MyMessage myMessage;
10         Map<String, Object> messageParam = new HashMap<>();
11         if ("SMS".equals(messageType)){
12             myMessage = new SMSMessage();
13             messageParam.put("phone_number", "123456789");
14         } else if ("OA".equals(messageType)){
15             myMessage = new OAMessage();
16             messageParam.put("OA_userName", "testUser");
17         } else if ("EMAIL".equals(messageType)){
18             myMessage = new EmailMessage();
19             messageParam.put("EMAIL", "test@test.com");
20         } else {
21             myMessage = new EmailMessage();
22             messageParam.put("EMAIL", "test@test.com");
23         }
24         myMessage.setMessageParam(messageParam);
25         return myMessage;
26     }
27 }

测试

 1 package com.test.factoryMethod;
 2 
 3 public class FactoryMethodTest {
 4     public static void main(String[] args){
 5         FactoryMethod messageFactory = new FactoryMethod1();
 6         MyMessage myMessage;
 7         try{
 8             myMessage = messageFactory.createMessage("SMS");
 9             myMessage.sendMessage();
10 
11             myMessage = messageFactory.createMessage("OA");
12             myMessage.sendMessage();
13 
14             myMessage = messageFactory.createMessage("EMAIL");
15             myMessage.sendMessage();
16 
17         } catch (Exception e) {
18             e.printStackTrace();
19         }
20     }
21 }

测试结果

1 package com.test.factoryMethod2;
2 
3 public interface Shape {
4     public abstract void draw(

posted on 2018-09-07 10:36 0820LL 阅读(114) 评论(0) 编辑收藏举报

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设计模式——工厂方法模式

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