java-异常-异常应用

package p1.exception;


/*
 * 老师用电脑上课。
 * 
 * 问题领域中涉及两个对象。
 * 老师，电脑。
 * 
 * 分析其中的问题。
 * 比如电脑蓝屏。冒烟。
 * 
 */

class LanPingException extends Exception{
    public LanPingException(String msg) {
        super(msg);
        // TODO Auto-generated constructor stub
    }
}
class MaoYanException extends Exception{
    public MaoYanException(String msg) {
        super(msg);
        // TODO Auto-generated constructor stub
    }
}
class NoPlanException extends Exception{
    public NoPlanException(String msg) {
        super(msg);
        // TODO Auto-generated constructor stub
    }
}
class Computer{
    private int state = 2;
    
    public void run() throws LanPingException,MaoYanException{
        if (state == 1) {
            throw new LanPingException("电脑蓝屏");
        }
        if (state == 2) {
            throw new MaoYanException("电脑冒烟");
        }
        System.out.println("电脑运行");
    }
    public void reset() {
        state = 0;
        System.out.println("电脑重启");
    }
}
class Teacher{
    private String name;
    private Computer comp;
    public Teacher(String name) {
        this.name = name;
        comp = new Computer();
        // TODO Auto-generated constructor stub
    }
    public void prelect() throws NoPlanException{
        try {
            comp.run();
            System.out.println(name+"讲课");
        } catch (LanPingException e) {
            System.out.println(e.toString());
            comp.reset();
            prelect();
            
        } catch (MaoYanException e) {
            
            System.out.println(e.toString());
            test();
            //可以对电脑进行维修，
//            throw e;//做练习但没有解决冒烟问题抛出给别人
            throw new NoPlanException("课时进度无法完成，原因："+e.getMessage());
            
        }
        
        
    }
    public void test() {
        System.out.println("大家练习");
    }
}
public class ExceptionTest {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Teacher t = new Teacher("武老师");
        try {
            t.prelect();
        } catch (NoPlanException e) {
            System.out.println(e.toString()+"......");
            System.out.println("换人");
        }
        
    }

}

/*
 * class NoAddException extends Exception{
 * 
 * }
 * 
 * 
 * void addData(Data d) throws NoAddException{
 * 
 *         连接数据库
 *         try{
 *             添加数据。出现异常 SQLException();
 *         }catche (SQLException e) {
 *             //处理代码
 * 
 *             thorw new NoAddException();     内部处理了异常对外进行异常的转换，也叫异常的封装
 *                                             不该暴露出的问题就不暴露，你暴露了对方也不能处理
 *                                             
 *         }finally{
 *             关闭数据库
 *         }
 *         
 * 
 * 
 * 
 */ 
 * }