day09-12-面向对象（ExceptionTest）

需求：毕老师用电脑上课
1.开始思考上课中出现的问题：1.电脑蓝屏2.电脑冒烟
2.要对问题进行描述，封装成对象。
可是当冒烟发生后，出现讲课进度无法继续
出现了讲师的问题，课程计划无法完成

//定义蓝屏异常，封装成对象
class LanPingException extends Exception
{
    LanPingException(String message)
    {
        super(message);//父类Exception有getMessage方法，用super调用，无需重写
    }
}
//定义冒烟异常，封装成对象，
class MaoYanException extends Exception
{
    MaoYanException(String message)
    {
        super(message);
    }
}
//课时无法完成异常，封装成对象
class NoPlanException extends Exception
{
    NoPlanException(String message)
    {
        super(message);
    }
}

class Computer
{
    private int state = 3;
    public void run() throws LanPingException,MaoYanException
    {
        if(state==2)
            throw new LanPingException("蓝屏了");
        if(state==3)
            throw new MaoYanException("冒烟了");
        System.out.println("电脑运行啦");
    }
    public void reset()
    {
        state = 1;
        System.out.println("电脑重启");
    }
}

class Teacher
{
    private String name;
    private Computer cmpt;
    Teacher(String name)
    {
        this.name = name;
        cmpt = new Computer();//老师一初始化就有电脑
    }
    public void prelect()throws NoPlanException
    {
        try
        {
            cmpt.run();
        }
        catch(LanPingException e)
        {
            cmpt.reset();
        }
        catch(MaoYanException e)
        {
            test();
            //创建 NoPlanException，函数上声明NoPlanException后，抛给主函数，主函数try catch
            throw new NoPlanException("课时无法继续"+e.getMessage());
        }
        System.out.println("讲课");
    }
    public void test()
    {
        System.out.println("练习");
    }
}
class ExceptionTest
{
    public static void main(String[] args)
    {
        Teacher t = new Teacher("毕老师");
        try
        {
            t.prelect();
        }
        catch (NoPlanException e)
        {
            System.out.println(e.toString());
            System.out.println("换老师或者放假");
        }
    }
}