一分钟学会系列：设计模式替换IF ELSE代码

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/t1g2q3/article/details/88067941

public void sendMessage(String type){
    if("sms".equals(type)){
        sendSms();
    }else if("email".equals(type)){
        sendEmail();
    }
    ...
}

/**
 * 模板引擎基类
 * 所有模板类继承此类
 * @author 李熠
 *
 */
public abstract class Template {

    //发送消息
    public abstract void send(String jsonData)throws Exception;

}


//短信模板
public class SmsTemplate extends Template {

    @Override
    public void send(String jsonData)throws Exception{
        // do something ...    
    }

}


public class TemplateFactory {

    public static Template create(Type type){
        Template template = null;
        switch (type){
            case SMS:
                template = new SmsTemplate();
                break;
            case EMAIL:
                template = new EmailTemplate();
                break;
        }
        return template;
    }

    public static void main(String[] args) {
        Template template = TemplateFactory.create(Type.SMS);
        template.send(...);
    }
}

if(情况1){
    执行策略1
}else if(情况2){
    执行策略2
}

public interface Strategy {

    /**
     * 策略方法
     */
    void strategyInterface();
}
public class ConcreteStrategyA implements Strategy{

    @Override
    public void strategyInterface() {
        System.out.println("实现策略1");
    }
}
public class Context {

    //持有一个具体策略的对象
    private Strategy strategy;
    /**
     * 构造函数，传入一个具体策略对象
     * @param strategy    具体策略对象
     */
    public Context(Strategy strategy){
        this.strategy = strategy;
    }
    /**
     * 策略方法
     */
    public void contextInterface(){
        strategy.strategyInterface();
    }
    public static void executeStrategy(int type){
        Strategy strategy = null;
        if(type == 1){
            strategy = new ConcreteStrategyA();
        }
        Context context = new Context(strategy);
        context.contextInterface();
    }

    public static void main(String[] args) {
        Context.executeStrategy(1);
    }
}