Java 自定义异常

public class ScaryException extends Exception {
	
	public ScaryException() {
		super();
	}
	
	public ScaryException(String message) {
		super(message);
	}
	
	public ScaryException(String message, Throwable cause ) {
		super(message, cause);
	}
	
	public ScaryException(Throwable cause) {
		super(cause);
	}

}
public class TestExceptions {

	public static void doRisky(String test) throws ScaryException {
		
		System.out.println("start risky......");
		//用Object 引用 String 类，是因为 Object 本身是String 类的父类
		//拥有 String 类重写的方法。
		if ("yes".equals(test)) {
			throw new ScaryException();
		}
		System.out.println("end risky......");
	}
	
	public static void main(String[] args) {
		
		String test = "no";
		try {
			System.out.println("start try......");
			doRisky(test);
			System.out.println("end try......");
		} catch (ScaryException se) {
			System.out.println("scary exception");
		} finally {
			System.out.println("finally......");
		}
		
		System.out.println("end of main.");

	}

}

class BaseballException extends Exception {}
class Foul extends BaseballException {}
class Strike extends BaseballException {}

abstract class Inning {
	public Inning() throws BaseballException {}
	public void event()  throws BaseballException {
		
	}
	public abstract void atBat() throws Strike, Foul;
	public void walk() {}
}

class StormException extends Exception {}
class RainedOut extends StormException {}
class PopFoul extends Foul {}

interface Storm {
	public void event();
	public void rainHard() throws RainedOut;
}

public class StormyInning extends Inning implements Storm {
	// 构造函数可以添加新的异常，但是必须处理父类的异常
	public StormyInning() throws RainedOut, BaseballException {
	}
	
	public StormyInning(String s) throws Foul, BaseballException {
	}
	/* 父类的方法没有异常的不能添加异常
	public void walk() throws PopFoul {
		
	}*/
	// 接口不能为父类中存在的方法添加异常
	public void event() {
		
	}
	
	
	@Override
	public void rainHard() throws RainedOut {
		// TODO Auto-generated method stub
		
	}
	// 可以窄化抛出的异常 PopFoul 可以用来替换 Strike, Foul
	@Override
	public void atBat() throws Strike, Foul {
		// TODO Auto-generated method stub
		
	}
	
}