lower version, for example 2.6.8
```properties
dubbo.provider.version=1.0
```

2.7.6 failed to recognize the provider url with 'default.version=1.0' key,  it only takes 'version.1.0' into consideration.

return StringUtils.isEmpty(value) ? defaultValue : COMMA_SPLIT_PATTERN.split(value);
    }
    public List<String> getParameter(String key, List<String> defaultValue) {
        String value = getParameter(key);
        if (StringUtils.isEmpty(value)) {
            return defaultValue;
        }
        String[] strArray = COMMA_SPLIT_PATTERN.split(value);
        return Arrays.asList(strArray);
    }
    private Map<String, Number> getNumbers() {
        
        if (numbers == null) {
            numbers = new ConcurrentHashMap<>();
        }
        return numbers;
    }
    private Map<String, Map<String, Number>> getMethodNumbers() {
        if (methodNumbers == null) { 
            methodNumbers = new ConcurrentHashMap<>();
        }
        return methodNumbers;
    }
    private Map<String, URL> getUrls() {
        
        if (urls == null) {
            urls = new ConcurrentHashMap<>();
        }
        return urls;
    }