2018/01/02常见异常处理

1）自己自作主张改写的原站长[武器类Weapon（继承类Item）]的代码案例如下：

/**
 * Description
 * <br> this's a test class
 * Created by test on 2018/01/02
 * @author peaceful water
 *
 */
public class Hero {
    public  class Weapon {
        int damage;//多了一个属性
        String name;
        int price;
    }
    public static void main(String[] args) {
        Weapon infinityEdge = new Weapon();
        infinityEdge.damage = 65; //damage属性在类Weapon中新设计的
        
        infinityEdge.name = "无尽之刃";//name属性，是从Item中继承来的，就不需要重复设计了
        infinityEdge.price = 3600;
    }
}

出现异常提示：

Exception in thread "main" java.lang.Error: Unresolved compilation problem: 
    No enclosing instance of type Hero is accessible. Must qualify the allocation with an enclosing instance of type Hero (e.g. x.new A() where x is an instance of Hero).

    at Hero.main(Hero.java:19)

解决方法：将第9行代码修改为：public static class Weapon。

原因如下：起初写的内部类Weapon是动态的，也就是开头以public class开头。而主程序是public static class main[即静态方法]。在Java中，类中的静态方法不能直接调用动态方法。只有将某个内部类修饰为静态类，然后才能够在静态类中调用该类的成员变量与成员方法。所以解决办法是将public class改为public static class.

参考链接：Java出现No enclosing instance of type E is accessible. Must qualify the allocatio