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.

if (defaultValue <= 0) {
            throw new IllegalArgumentException("defaultValue <= 0");
        }
        short value = getParameter(key, defaultValue);
        return value <= 0 ? defaultValue : value;
    }
    public byte getPositiveParameter(String key, byte defaultValue) {
        if (defaultValue <= 0) {
            throw new IllegalArgumentException("defaultValue <= 0");
        }
        byte value = getParameter(key, defaultValue);
        return value <= 0 ? defaultValue : value;
    }
    public char getParameter(String key, char defaultValue) {
        String value = getParameter(key);
        return StringUtils.isEmpty(value) ? defaultValue : value.charAt(0);
    }
    public boolean getParameter(String key, boolean defaultValue) {
        String value = getParameter(key);
        return StringUtils.isEmpty(value) ? defaultValue : Boolean.parseBoolean(value);
    }
    public boolean hasParameter(String key) {
        String value = getParameter(key);
        return value != null && value.length() > 0;
    }
    public String getMethodParameterAndDecoded(String method, String key) {
        return URL.decode(getMethodParameter(method, key));
    }
    public String getMethodParameterAndDecoded(String method, String key, String defaultValue) {
        return URL.decode(getMethodParameter(method, key, defaultValue));