策略模式+工厂模式-解决if else

Posted 2023-03-30 yan0219n

public interface strategy extends InitializingBean

void handler(JsonObject z2CmdReq);

public class CtrlInnerPolicyStrategy implements strategy

@Override

public void handler(JsonObject z2CmdReq)

//TODO

@Override

public void afterPropertiesSet()

CmdStrategyFactory.register(CmdTypeConstant.CTRL_INNER_POLICY,this);

@Component

public class CmdStrategyFactory

private static Map<String,Strategy> map = new HashMap<>();

public static Strategy getSpecStrategy(String cmd)

return map.get(cmd);

public static void register(String cmd,Strategy handler)

if(StringUtils.isEmpty() &&null == handler)

return;

map.put(cmd,handler);

使用：

CmdStrategyFactory.getSpecStrategy(z2CmdReq.getCmdType()).handler(JsonObject z2CmdReq);

策略模式+工厂方法消除if...else

今天来讲一下如何通过策略模式和工厂方法来消除累赘的if...else，具体什么是策略模式，大家可以自行百度学习，我就不再这里做过多的介绍了。

注意：如果业务场景简单，建议使用if...else，因为代码逻辑简单，便于理解

策略接口

Eat.java

/**
 * 策略接口
 *
 */
public interface Eat 
    
    public void eatFruit(String fruit);
    

策略类

EatApple.java

/**
 * 具体的策略类：吃苹果
 */
public class EatApple implements Eat
    
    @Override
    public void eatFruit(String fruit) 
        System.out.println("吃苹果");
    

EatBanana.java

/**
 * 具体的策略类：吃香蕉
 */
public class EatBanana implements Eat 

    @Override
    public void eatFruit(String fruit) 
        System.out.println("吃香蕉");
    

EatPear.java

/**
 * 具体的策略类：吃梨
 */
public class EatPear implements Eat 

    @Override
    public void eatFruit(String fruit) 
        System.out.println("吃梨");
    

策略上下文

EatContext.java

/**
 * 策略上下文
 */
public class EatContext 

    private Eat eat;

    public EatContext(Eat eat) 
        this.eat = eat;
    
    
    public void eatContext(String fruit) 
        eat.eatFruit(fruit);
    
    

策略工厂类

EatFactory.java

/**
 * 策略工厂类
 */
public class EatFactory 

    private static Map<String, Eat> map = new HashMap<>();
    
    static 
        map.put("apple", new EatApple());
        map.put("banana", new EatBanana());
        map.put("pear", new EatPear());
    
    
    public static Eat getEatStrategy(String fruitType) 
        return map.get(fruitType);
    

测试

public class Demo 

    public static void main(String[] args) 
        String fruit = "apple";
        // 传入具体水果类型，得到苹果策略接口
        Eat eat = EatFactory.getEatStrategy(fruit);
        // 调用具体策略方法
        eat.eatFruit(fruit);
    

测试结果：

吃苹果

第一次写博客，写的不好的地方，还望大家留言指教！