各位大神，不好意思，问错了，问题已解决

public Element(String name, String uri) {
        
        // The shadowing is important here.
        // I don't want to set the prefix field just yet.
        String prefix = "";
        String localName = name;
        int colon = name.indexOf(':');
        if (colon > 0) {
            prefix = name.substring(0, colon);   
            localName = name.substring(colon + 1);   
        }
        
        // The order of these next two calls
        // matters a great deal.
        _setNamespacePrefix(prefix);
        _setNamespaceURI(uri);
        try {
            _setLocalName(localName);
        }
        catch (IllegalNameException ex) {
            ex.setData(name);
            throw ex;
        }
        
    }

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java 语言