Java Web Service返回带有>和<而不是>和的字符串

Question

I have a java web service that returns a string. I'm creating the body of this xml string with a DocumentBuilder and Document class. When I view source of the returned XML (Which looks fine in the browser window) instead of <> it's returning < and > around the XML nodes.

Please help.

The code is not including any error catching, it was stripped for simplicity. One code block and three methods are included: The first code block (EXAMPLE SETUP) shows the basics of what the Document object is setup to be like. the method appendPayment(...) is where the actual document building happens. It calls on two helper methods getTagValue(...) and prepareElement(...)
**Note, this code is meant to copy specific parts from a pre-existing xml string, xmlString , and grap the necessary information to be returned later.

Response added at the end of the question

How to return arbitrary XML Document using an Eclipse/AXIS2 POJO Service

EXAMPLE SETUP
{
    //create new document
    DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder newDocBuilder = docFactory.newDocumentBuilder();
    Document newDoc = newDocBuilder.newDocument();
    Element rootElement = newDoc.createElement("AllTransactions");

    newDoc.appendChild(rootElement);
    appendPayment(stringXML, newDoc);
}

public static void appendPayment(String xmlString, Document newDoc) throws Exception
{
    //convert string to inputstream
    ByteArrayInputStream bais = new ByteArrayInputStream(xmlString.getBytes());
    DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
    DocumentBuilder docBuilder = docFactory.newDocumentBuilder();
    Document oldDoc =   docBuilder.parse(bais);
    oldDoc.getDocumentElement().normalize();            

    NodeList nList = oldDoc.getChildNodes();
    Node nNode = nList.item(0);
    Element eElement = (Element) nNode;

    //Create new child node for this payment
    Element transaction = newDoc.createElement("Transaction");
    newDoc.getDocumentElement().appendChild(transaction);


    //status
    transaction.appendChild(prepareElement("status", eElement, newDoc));

    //amount
    transaction.appendChild(prepareElement("amount", eElement, newDoc));
}

private static String getTagValue(String sTag, Element eElement)
{
    NodeList nlList = eElement.getElementsByTagName(sTag).item(0).getChildNodes();
    Node nValue = (Node) nlList.item(0);
    return nValue.getNodeValue();
}

private static Element prepareElement(String sTag, Element eElement, Document newDoc)
{
    String str = getTagValue(sTag, eElement);
    Element newElement = newDoc.createElement(sTag);
    newElement.appendChild(newDoc.createTextNode(str));
    return newElement;
}

Finally, I use the following method to convert the final Document object to a String

public static String getStringFromDocument(Document doc)
{
    try
    {
       DOMSource domSource = new DOMSource(doc);
       StringWriter writer = new StringWriter();
       StreamResult result = new StreamResult(writer);
       TransformerFactory tf = TransformerFactory.newInstance();
       Transformer transformer = tf.newTransformer();
       transformer.transform(domSource, result);
       return writer.toString();
    }
    catch(TransformerException ex)
    {
       ex.printStackTrace();
       return null;
    }
}

The header type of the response is as follows

Server: Apache-Coyote/1.1
Content-Type: text/xml;charset=utf-8
Transfer-Encoding: chunked

This is an example response

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/"
    xmlns:xsd="http://www.w3.org/2001/XMLSchema"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <soapenv:Body>
        <getTransactionsResponse xmlns="http://services.paypal.com">
        <getTransactionsReturn>&lt;AllTransactions&gt;&lt;Transaction&gt;&lt;status&gt;PENDING&lt;/status&gt;&lt;amount&gt;55.55&lt;/amount&gt;&lt;/transaction&gt;
        </getTransactionsResponse>
    </soapenv:Body>
</soapenv:Envelope>

Answer 1

The framework is doing what you tell it; your method returns a String which means the generated WSDL should have a response message of type <xsd:string> . As we know, XML strings must encode certain characters as character entity references (ie " < " becomes " < " so the XML parser treats it as a string, not the beginning of an XML element as you intend). If you want to return an XML document then you must define the XML structure in the WSDL <types> section and set the response message part to the appropriate element.

To put it another way, you are trying to send "typed" data without using the strong type system provided by SOAP/WSDL (namely XML schema); this is generally regarded as bad design (see Loosely typed versus strongly typed web services ).

The ultimate solution is to to define the response document via a proper XML Schema . If there is no set schema, as by the design of your service, then use the <xsd:any> type for the message response type, although this approach has its pitfalls . Moreover, such a redesign implies a schema-first (top-down) development model and from the comment stream it seems that you are currently practicing code-first (bottom-up) approach. Perhaps your tools provide a mechanism such as a "general XML document" return type or annotation which achieves the same effect.