1. non-simplify mode:
```
dubbo://120.0.0.1:20880/org.apache.dubbo.demo.DemoService?key=value
```
the store path of ZK will be: `/dubbo/porg.apache.dubbo.demo.DemoService/url`

2. simplify mode:
```
dubbo://120.0.0.1:20880/org.apache.dubbo.demo.DemoService?key=value
```
the store path of ZK will be: `/dubbo/porg.apache.dubbo.demo.DemoService/url`

3. simplify mode with path specified:
```
dubbo://120.0.0.1:20880/path-value?key=value
```
the store path of ZK will be: `/dubbo/path-value/url`
if (StringUtils.isEmpty(username)
                && StringUtils.isNotEmpty(password)) {
            throw new IllegalArgumentException("Invalid url, password without username!");
        }
        this.protocol = protocol;
        this.username = username;
        this.password = password;
        this.host = host;
        this.port = (port < 0 ? 0 : port);
        
        while (path != null && path.startsWith("/")) {
            path = path.substring(1);
        }
        this.path = path;
        if (parameters == null) {
            parameters = new HashMap<>();
        } else {
            parameters = new HashMap<>(parameters);
        }
        this.parameters = Collections.unmodifiableMap(parameters);
    }
    /**
     * Parse url string
     *
     * @param url URL string
     * @return URL instance
     * @see URL
     */
    public static URL valueOf(String url) {
        if (url == null || (url = url.trim()).length() == 0) {