浅谈JAVA设计模式之——状态模式（State）

package com.lyz.design.state;
/**
 * Context 
 * @author binghe
 *
 */
public class Context {
    private Weather weather;
    public void setWeather(Weather weather) {
        this.weather = weather;
    }
    public Weather getWeather() {
        return this.weather;
    }
    public String weatherMessage() {
        return weather.getWeather();
    }
}

package com.lyz.design.state;
/**
 * State 
 * @author binghe
 *
 */
public interface Weather {
    String getWeather();
}

package com.lyz.design.state;
/**
 * ConcreteStatesubclasses 
 * @author binghe
 *
 */
public class Rain implements Weather {
    public String getWeather() {
        return "下雨";
    }
}

package com.lyz.design.state;
/**
 * ConcreteStatesubclasses 
 * @author binghe
 *
 */
public class Sunshine implements Weather {
    public String getWeather() {
        return "阳光";
    }
}

package com.lyz.design.state;
/**
 * Test
 * @author binghe
 *
 */
public class Test{
    public static void main(String[] args) {
        Context ctx1 = new Context();
        ctx1.setWeather(new Sunshine());
        System.out.println(ctx1.weatherMessage());
        System.out.println("===============");
        Context ctx2 = new Context();
        ctx2.setWeather(new Rain());
        System.out.println(ctx2.weatherMessage());
    }
}

阳光
===============
下雨