35. 例外定義

35. 例外定義

独自の例外を定義

l:\lesson087\test.java

class test {
    public static void main(String args[]) {
        try {
            ThrowException();
        }
        catch (Exception err) {
            System.out.println(err);
        }
    }

    static void ThrowException() throws MyException {
        throw new MyException("ThrowException() の例外");
    }
}

class MyException extends Exception {
    public MyException(String msg) { super(msg); }
}

実行結果

L:\lesson087>java test

MyException: ThrowException() の例外

例外の可能性を報告

l:\lesson088\test.java

class test {
    public static void main(String args[]) throws MyException {
        ThrowException();
    }

    static void ThrowException() throws MyException {
        throw new MyException("ThrowException() の例外");
    }
}

class MyException extends Exception {
    public MyException(String msg) { super(msg); }
}

実行結果

L:\lesson088>java test

Exception in thread "main" MyException: ThrowException() の例外

        at test.ThrowException(test.java:7)

        at test.main(test.java:3)