Java JAXB解组链接异常

Question

Background: I am trying to parse XML into object using JAXB unmarshaller.

What I've done: I used JAXB itself to generate object classes and wrote some methods to unmarshal xml.

public void xmlParser() {
    try {
        Acquirer acquirer = (Acquirer) readXml(Constants.XML_PATH);
        System.out.println(acquirer.getDate());
    } catch (JAXBException | IOException e) {
        e.printStackTrace();
    }
}

/**
 * Initializes of JAXB Context and Unmarshaller.
 */
private static void createContext() {
    try {
        jaxbContext = JAXBContext.newInstance("com.test.xml.generated");
        unmarshaller = jaxbContext.createUnmarshaller();
    } catch (JAXBException e) {
        e.printStackTrace();
    }
}

/**
 * This reads the XML file from the resources in ClassPath.
 *
 * @param xmlFile XML file name as String with relative ClassPath
 * @return Unmarashalled XML file
 * @throws JAXBException
 * @throws IOException
 * @throws Exception
 */
public Object readXml(String xmlFile) throws JAXBException, IOException {
    if (jaxbContext == null) {
        createContext();
    }

    InputStream stream = getClass().getClassLoader().getResourceAsStream(xmlFile);
    BufferedInputStream buffredStream = new BufferedInputStream(stream);

***Error:***
    Object obj = unmarshaller.unmarshal(buffredStream);
    buffredStream.close();
    stream.close();
    return obj;

 }

Error is in Object obj.....

Exception:

javax.xml.bind.UnmarshalException - with linked exception:
[java.io.IOException: Stream closed]
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal0(UnmarshallerImpl.java:246)
at com.sun.xml.internal.bind.v2.runtime.unmarshaller.UnmarshallerImpl.unmarshal(UnmarshallerImpl.java:214)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:157)
at javax.xml.bind.helpers.AbstractUnmarshallerImpl.unmarshal(AbstractUnmarshallerImpl.java:125)

What I've managed to search: I used xml validator to validate xml and it seems fine. I also saw that someone suggested not to use InputStream and etc.. So I tried using File file = new File(); nothing. Moreover I tried to check auto generated object classes, but didn't find anything suspicious. @XmlElement and Root seems to be defined just fine.

PS I have xsd scheme of this xml (I generated all object classes using this xsd). I even used online tools to validate them both and everything seems right.

Constants.XML_PATH = "/Acquirer.xml";

Answer 1

Simply change:

InputStream stream = getClass().getClassLoader().getResourceAsStream(xmlFile);

on:

InputStream stream = getClass().getResourceAsStream(xmlFile);

Because when you use getClass().getClassLoader().getResourceAsStream(xmlFile) then it returns null (does not find the resource) and BufferedInputStream then throws the IOException when providing null instead of input stream instance into constructor.