public String getString( String key ) {
    verifyIsNull();
    Object o = get( key );
    if( o != null ){
        return o.toString();//非空强转的过程
    }
    throw new JSONException( "JSONObject[" + JSONUtils.quote( key ) + "] not found." );
}

public int getInt(String key) {
        verifyIsNull();
        Object o = get(key);
        if (o != null) {
            return o instanceof Number ? ((Number) o).intValue() : (int) getDouble(key);
        }
        throw new JSONException("JSONObject[" + JSONUtils.quote(key) + "] is not a number.");
    }