算法策略的主动选择,拒绝if...else...(策略模式+简单工厂模式)

本文通过一个切换加解密算法的Demo来学习如何使代码的调用和封装都变的更加简单

1. 抽象策略接口

 /**
 * 加密算法接口:封装算法的公共操作加密和解密
 * 
 * @author Spoon
 * @version 1.0.0
 */
public interface SecurityStrategy {
	/**
	 * 加密
	 */
	public String doEncryption(String key, String plaintext);
 
	/**
	 * 解密
	 */
	public String doDeciphering(String key, String ciphertext);
}

2. 策略算法的具体实现

 /**
 * AES加密算法具体实现类
 * 
 * @author Spoon
 * @version 1.0.0
 */
public class AesStrategy implements SecurityStrategy{
 
	@Override
	public String doEncryption(String key, String plaintext) {
		String dec = "";
		try {
			dec = AESUtil.encrypt(plaintext, key, "UTF-8");
		} catch (Exception e) {
			e.printStackTrace();
		}
		return dec;
	}
 
	@Override
	public String doDeciphering(String key, String ciphertext) {
		String enc = "";
		try {
			enc = AESUtil.decrypt(ciphertext, key);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return enc;
	}
 
}

 /**
 * DES3加密算法具体实现类
 *
 * @author Spoon
 * @version 1.0.0
 */
public class Des3Strategy implements SecurityStrategy{
 
	@Override
	public String doEncryption(String key, String plaintext) {
		String dec = "";
		try {
			dec = ThreeDES.encode(plaintext, key);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return dec;
	}
 
	@Override
	public String doDeciphering(String key, String ciphertext) {
		String enc = "";
		try {
			enc = ThreeDES.decode(ciphertext, key);
		} catch (Exception e) {
			e.printStackTrace();
		}
		return enc;
	}
 
}

3. 加密算法类型枚举

 /**
 * 加密算法类型枚举
 * @author Spoon
 * @version 1.0.0
 */
public enum StrategyType {
	AES(1,"AES加密算法"), 
	DES3(2,"DES3加密算法");
	
	private int index;
	private String desc;
    
	private StrategyType(int index, String desc){
		this.index = index;
		this.desc = desc;
	}
 
	public int index() {
		return index;
	}
 
	public String desc() {
		return desc;
	}
}

4. 使用简单工厂获取具体实现

 /**
 * 策略工厂类:将每个实现策略注册到工厂,并根据Type返回指定策略实现 
 
 * @author Spoon
 * @version 1.0.0
 */
public class StrategyFactory {
	private static Map<Integer, SecurityStrategy> services = new ConcurrentHashMap<Integer, SecurityStrategy>();
 
	static {
		services.put(StrategyType.AES.index(), new AesStrategy());
		services.put(StrategyType.DES3.index(), new Des3Strategy());
	}
 
	private StrategyFactory() {
	}
 
	public static SecurityStrategy getSecurity(Integer type) {
		return services.get(type);
	}
}

5. 策略上下文完成工厂返回实现的具体调用

 /**
 * 策略上下文:实际操作对象,接收传入的Type和必要参数,内部调用策略工厂类获取实际实现类进行加解密操作
 * 
 * @author Spoon
 * @version 1.0.0
 */
public class StrategyContext {
	private SecurityStrategy strategy;
 
	public StrategyContext() {
	}
 
	public SecurityStrategy getStrategy() {
		return strategy;
	}
 
	public void setStrategy(SecurityStrategy strategy) {
		this.strategy = strategy;
	}
 
	public String executeEncryptionStrategy(Integer type, String key, String plaintext) {
		strategy = StrategyFactory.getSecurity(type);
		return strategy.doEncryption(key, plaintext);
	}
 
	public String executeDecipheringStrategy(Integer type, String key, String ciphertext) {
		strategy = StrategyFactory.getSecurity(type);
		return strategy.doDeciphering(key, ciphertext);
	}
}

6. Test

 /**
 *  测试类
 * 	String key_aes = "789tenc963qAzWsX";
 * 	String key_des3 = "1234567890ASDFGH12345678";
 */
public class Main {
	@SuppressWarnings("resource")
	public static void main(String[] args) {
		
		String plaintext = "ABCDEFGHIJKLMNOPQRST";
		
		System.out.println("请选择加密算法(AES:1, DES3:2) :");
		int type = new Scanner(System.in).nextInt();
		
		System.out.println("请输入加密秘钥 :");
		String key = new Scanner(System.in).nextLine();
		
		StrategyContext context = new StrategyContext();
		System.out.println(context.executeEncryptionStrategy(type, key, plaintext));
	}
}

通过测试Main方法可以看出,在增加加密算法后对调用方来说只需要关注加密算法的Type值就可以,调用形式也没有发生改变,没有使用条件语句进行判断,减少了调用时出错的风险,对于提供方来说,主要关注点就是策略算法的具体实现,并添加相应的枚举后将实现的策略注册到策略工厂中即可。

Python版本 :

 from abc import ABCMeta,abstractmethod
 
 
class SecurityStrategy:
    __metaclass__ = ABCMeta  # 指定这是一个抽象类
 
    @abstractmethod  # 抽象方法
    def doEncryption(self, key, plaintext):
        pass
 
    @abstractmethod  # 抽象方法
    def doDeciphering(self, key, ciphertext):
        pass

 from SecurityStrategy import SecurityStrategy
 
 
class AesStrategy(SecurityStrategy):
    def doEncryption(self, key, plaintext):
        print('AES === > ', 'key : ', key, 'plaintext : ', plaintext)
 
    def doDeciphering(self, key, ciphertext):
        print('AES === > ', 'key : ', key, 'ciphertext : ', ciphertext)

 from SecurityStrategy import SecurityStrategy
 
 
class Des3Strategy(SecurityStrategy):
    def doEncryption(self, key, plaintext):
        print('Des3 === > ', 'key : ', key, 'plaintext : ', plaintext)
 
    def doDeciphering(self, key, ciphertext):
        print('Des3 === > ', 'key : ', key, 'ciphertext : ', ciphertext)

 from enum import Enum
 
 
class StrategyType(Enum):
    AES = 1
    DES3 = 2

 from StrategyType import StrategyType
from impl.AesStrategy import AesStrategy
from impl.Des3Strategy import Des3Strategy
 
 
class StrategyFactory:
    services = {
        StrategyType.AES.value: AesStrategy(),
        StrategyType.DES3.value: Des3Strategy()
    }
 
    @staticmethod
    def getSecurity(type):
        return StrategyFactory.services[type]

 from StrategyFactory import StrategyFactory
 
 
class StrategyContext:
 
    @staticmethod
    def executeEncryptionStrategy(type, key, plaintext):
        return StrategyFactory.getSecurity(type).doEncryption(key, plaintext)
 
    @staticmethod
    def executeDecipheringStrategy(type, key, ciphertext):
        return StrategyFactory.getSecurity(type).doDeciphering(key, ciphertext)

 from StrategyContext import StrategyContext
 
if __name__ == '__main__':
    print("---------------开始测试-------------------")
    StrategyContext.executeEncryptionStrategy(1, '1234567890ASDFGH12345678', 'ABCDEFGHIJKLMNOPQRST')
    StrategyContext.executeDecipheringStrategy(1, '1234567890ASDFGH12345678', 'ABCDEFGHIJKLMNOPQRST')
    StrategyContext.executeEncryptionStrategy(2, '1234567890ASDFGH12345678', 'ABCDEFGHIJKLMNOPQRST')
    StrategyContext.executeDecipheringStrategy(2, '1234567890ASDFGH12345678', 'ABCDEFGHIJKLMNOPQRST')
    print("---------------结束测试-------------------")

posted @ 2020-05-31 21:58 前端小鑫同学阅读(4) 评论(0) 编辑收藏举报来源

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算法策略的主动选择,拒绝if...else...(策略模式+简单工厂模式)

算法策略的主动选择,拒绝if...else...(策略模式+简单工厂模式)

1. 抽象策略接口

2. 策略算法的具体实现

3. 加密算法类型枚举

4. 使用简单工厂获取具体实现

5. 策略上下文完成工厂返回实现的具体调用

6. Test

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	/**
	* 加密算法接口:封装算法的公共操作加密和解密
	*
	* @author Spoon
	* @version 1.0.0
	*/
	public interface SecurityStrategy {
	/**
	* 加密
	*/
	public String doEncryption(String key, String plaintext);

	/**
	* 解密
	*/
	public String doDeciphering(String key, String ciphertext);
	}

	/**
	* AES加密算法具体实现类
	*
	* @author Spoon
	* @version 1.0.0
	*/
	public class AesStrategy implements SecurityStrategy{

	@Override
	public String doEncryption(String key, String plaintext) {
	String dec = "";
	try {
	dec = AESUtil.encrypt(plaintext, key, "UTF-8");
	} catch (Exception e) {
	e.printStackTrace();
	}
	return dec;
	}

	@Override
	public String doDeciphering(String key, String ciphertext) {
	String enc = "";
	try {
	enc = AESUtil.decrypt(ciphertext, key);
	} catch (Exception e) {
	e.printStackTrace();
	}
	return enc;
	}

	}

	/**
	* DES3加密算法具体实现类
	*
	* @author Spoon
	* @version 1.0.0
	*/
	public class Des3Strategy implements SecurityStrategy{

	@Override
	public String doEncryption(String key, String plaintext) {
	String dec = "";
	try {
	dec = ThreeDES.encode(plaintext, key);
	} catch (Exception e) {
	e.printStackTrace();
	}
	return dec;
	}

	@Override
	public String doDeciphering(String key, String ciphertext) {
	String enc = "";
	try {
	enc = ThreeDES.decode(ciphertext, key);
	} catch (Exception e) {
	e.printStackTrace();
	}
	return enc;
	}

	}

	/**
	* 加密算法类型枚举
	* @author Spoon
	* @version 1.0.0
	*/
	public enum StrategyType {
	AES(1,"AES加密算法"),
	DES3(2,"DES3加密算法");

	private int index;
	private String desc;

	private StrategyType(int index, String desc){
	this.index = index;
	this.desc = desc;
	}

	public int index() {
	return index;
	}

	public String desc() {
	return desc;
	}
	}

	/**
	* 策略工厂类:将每个实现策略注册到工厂,并根据Type返回指定策略实现

	* @author Spoon
	* @version 1.0.0
	*/
	public class StrategyFactory {
	private static Map<Integer, SecurityStrategy> services = new ConcurrentHashMap<Integer, SecurityStrategy>();

	static {
	services.put(StrategyType.AES.index(), new AesStrategy());
	services.put(StrategyType.DES3.index(), new Des3Strategy());
	}

	private StrategyFactory() {
	}

	public static SecurityStrategy getSecurity(Integer type) {
	return services.get(type);
	}
	}

	/**
	* 策略上下文:实际操作对象,接收传入的Type和必要参数,内部调用策略工厂类获取实际实现类进行加解密操作
	*
	* @author Spoon
	* @version 1.0.0
	*/
	public class StrategyContext {
	private SecurityStrategy strategy;

	public StrategyContext() {
	}

	public SecurityStrategy getStrategy() {
	return strategy;
	}

	public void setStrategy(SecurityStrategy strategy) {
	this.strategy = strategy;
	}

	public String executeEncryptionStrategy(Integer type, String key, String plaintext) {
	strategy = StrategyFactory.getSecurity(type);
	return strategy.doEncryption(key, plaintext);
	}

	public String executeDecipheringStrategy(Integer type, String key, String ciphertext) {
	strategy = StrategyFactory.getSecurity(type);
	return strategy.doDeciphering(key, ciphertext);
	}
	}

	/**
	* 测试类
	* String key_aes = "789tenc963qAzWsX";
	* String key_des3 = "1234567890ASDFGH12345678";
	*/
	public class Main {
	@SuppressWarnings("resource")
	public static void main(String[] args) {

	String plaintext = "ABCDEFGHIJKLMNOPQRST";

	System.out.println("请选择加密算法(AES:1, DES3:2) :");
	int type = new Scanner(System.in).nextInt();

	System.out.println("请输入加密秘钥 :");
	String key = new Scanner(System.in).nextLine();

	StrategyContext context = new StrategyContext();
	System.out.println(context.executeEncryptionStrategy(type, key, plaintext));
	}
	}

	from abc import ABCMeta,abstractmethod


	class SecurityStrategy:
	__metaclass__ = ABCMeta # 指定这是一个抽象类

	@abstractmethod # 抽象方法
	def doEncryption(self, key, plaintext):
	pass

	@abstractmethod # 抽象方法
	def doDeciphering(self, key, ciphertext):
	pass

	from SecurityStrategy import SecurityStrategy


	class AesStrategy(SecurityStrategy):
	def doEncryption(self, key, plaintext):
	print('AES === > ', 'key : ', key, 'plaintext : ', plaintext)

	def doDeciphering(self, key, ciphertext):
	print('AES === > ', 'key : ', key, 'ciphertext : ', ciphertext)

	from SecurityStrategy import SecurityStrategy


	class Des3Strategy(SecurityStrategy):
	def doEncryption(self, key, plaintext):
	print('Des3 === > ', 'key : ', key, 'plaintext : ', plaintext)

	def doDeciphering(self, key, ciphertext):
	print('Des3 === > ', 'key : ', key, 'ciphertext : ', ciphertext)

	from enum import Enum


	class StrategyType(Enum):
	AES = 1
	DES3 = 2

	from StrategyType import StrategyType
	from impl.AesStrategy import AesStrategy
	from impl.Des3Strategy import Des3Strategy


	class StrategyFactory:
	services = {
	StrategyType.AES.value: AesStrategy(),
	StrategyType.DES3.value: Des3Strategy()
	}

	@staticmethod
	def getSecurity(type):
	return StrategyFactory.services[type]

	from StrategyFactory import StrategyFactory


	class StrategyContext:

	@staticmethod
	def executeEncryptionStrategy(type, key, plaintext):
	return StrategyFactory.getSecurity(type).doEncryption(key, plaintext)

	@staticmethod
	def executeDecipheringStrategy(type, key, ciphertext):
	return StrategyFactory.getSecurity(type).doDeciphering(key, ciphertext)

	from StrategyContext import StrategyContext

	if __name__ == '__main__':
	print("---------------开始测试-------------------")
	StrategyContext.executeEncryptionStrategy(1, '1234567890ASDFGH12345678', 'ABCDEFGHIJKLMNOPQRST')
	StrategyContext.executeDecipheringStrategy(1, '1234567890ASDFGH12345678', 'ABCDEFGHIJKLMNOPQRST')
	StrategyContext.executeEncryptionStrategy(2, '1234567890ASDFGH12345678', 'ABCDEFGHIJKLMNOPQRST')
	StrategyContext.executeDecipheringStrategy(2, '1234567890ASDFGH12345678', 'ABCDEFGHIJKLMNOPQRST')
	print("---------------结束测试-------------------")