XMLOutputFactoryImpl.java 文件源码

public javax.xml.stream.XMLStreamWriter createXMLStreamWriter(javax.xml.transform.Result result) throws javax.xml.stream.XMLStreamException {

        if (result instanceof StreamResult) {
            return createXMLStreamWriter((StreamResult) result, null);
        } else if (result instanceof DOMResult) {
            return new XMLDOMWriterImpl((DOMResult) result);
        } else if (result instanceof StAXResult) {
            if (((StAXResult) result).getXMLStreamWriter() != null) {
                return ((StAXResult) result).getXMLStreamWriter();
            } else {
                throw new java.lang.UnsupportedOperationException("Result of type " + result + " is not supported");
            }
        } else {
            if (result.getSystemId() !=null) {
                //this is not correct impl of SAXResult. Keep it for now for compatibility
                return createXMLStreamWriter(new StreamResult(result.getSystemId()));
            } else {
                throw new java.lang.UnsupportedOperationException("Result of type " + result + " is not supported. " +
                        "Supported result types are: DOMResult, StAXResult and StreamResult.");
            }
        }

    }