Question

有人能告诉我为什么我会收到此错误，以及如何解决问题？

线程“main”中的异常java.lang.NoClassDefFoundError：org / codehaus / stax2 / ri / Stax2ReaderAdapter 在org.codehaus.staxmate.dom.DOMConverter._build（DOMConverter.java:188）在org.codehaus.staxmate.dom.DOMConverter.buildDocument（DOMConverter.java:171）在org.codehaus.staxmate.dom.DOMConverter.buildDocument（DOMConverter.java:152）在org.codehaus.staxmate.dom.DOMConverter.buildDocument（DOMConverter.java:131） at xmlprocessing.api.STAXModifyCV.main（STAXModifyCV.java:68）引起：java.lang.ClassNotFoundException：org.codehaus.stax2.ri.Stax2ReaderAdapter 在java.net.URLClassLoader $ 1.run（URLClassLoader.java:202） at java.security.AccessController.doPrivileged（Native Method）在java.net.URLClassLoader.findClass（URLClassLoader.java:190） at java.lang.ClassLoader.loadClass（ClassLoader.java:307）在sun.misc.Launcher $ AppClassLoader.loadClass（Launcher.java:301）在java.lang.ClassLoader.loadClass（ClassLoader.java:248） ......还有5个 Java结果：1

我写了下面的代码：

    //-*-*-
    FileInputStream input = new FileInputStream("cv.xml");
    XMLStreamReader reader = XMLInputFactory.newInstance().createXMLStreamReader(input);
    BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

    //-*-*- get new entries from input stream
    System.out.println("<< Sahar CV >>\n -> Modify the first reference\n    ** Modify The Name **");
    System.out.print("    Enter degree : ");
    String degree = in.readLine();
    System.out.print("    Enter first name : ");
    String fName = in.readLine();
    System.out.print("    Enter last name : ");
    String lName = in.readLine();
    System.out.println("    ** Modify The Address ** ");
    System.out.print("    Enter new city : ");
    String newCity = in.readLine();
    System.out.print("    Enter new country : ");
    String newCountry = in.readLine();

    //-*-*- let the reader point at the first "reference" element
    int eventType;
    boolean ref = false, fname = false;
    while (!ref && reader.hasNext()) {
        eventType = reader.next();
        switch (eventType) {
            case XMLEvent.START_ELEMENT:
                if (reader.getLocalName().equalsIgnoreCase("references")) {
                    ref = true;
                    break;
                }
        }
    }
    System.out.println("I am here");

    //-*-*- start modification
    Document doc = new DOMConverter().buildDocument(reader);
    Element firstRef = (Element)doc.getElementsByTagName("reference").item(0);
    NodeList name = (NodeList)firstRef.getElementsByTagName("name");
    //-*-*- modify the degree (Dr. , Eng. , Dev. ,etc)
    Attr att = (Attr)name.item(0).getAttributes().item(0);
    ((Node)att).setNodeValue(degree);
    //-*-*- modify first name
    NodeList firstName = (NodeList)firstRef.getElementsByTagName("fname");
    NodeList firstNameChilds = (NodeList)firstName.item(0).getChildNodes();
    ((Node)firstNameChilds.item(0)).setNodeValue(fName);
    //-*-*- modify last name
    NodeList lastName = (NodeList)firstRef.getElementsByTagName("lname");
    NodeList lastNameChilds = (NodeList)lastName.item(0).getChildNodes();
    ((Node)lastNameChilds.item(0)).setNodeValue(lName);
    //-*-*- modify city
    NodeList city = (NodeList)firstRef.getElementsByTagName("city");
    NodeList cityChilds = (NodeList)city.item(0).getChildNodes();
    ((Node)cityChilds.item(0)).setNodeValue(newCity);
    //-*-*- modify country
    NodeList country = (NodeList)firstRef.getElementsByTagName("country");
    NodeList countryChilds = (NodeList)country.item(0).getChildNodes();
    ((Node)countryChilds.item(0)).setNodeValue(newCountry);

    reader.close();
    input.close();
    //-*-*- write DOM document
    FileOutputStream out = new FileOutputStream("cv.xml");
    XMLStreamWriter sw = XMLOutputFactory.newInstance().createXMLStreamWriter(out);

    new DOMConverter().writeDocument(doc, sw);
    sw.close();
    out.close();

Answer 1

你需要确保正确的Woodstox在你的道路上。基本上，您正在使用在该jar中实现的类，但由于jar不在路径中，因此Java不知道您引用了哪个类。

Answer 2

这意味着找到了一个不包含预期类的.class文件，因为该包与目录结构不对应，或者因为文件在编译后被重命名。还有其他原因，但这是最常见的。

Answer 3

抱歉，我对3个答案投了反对，但突然有了疑问，需要仔细检查我的想法......结果却比我想象的要复杂得多。但是我在这里找到了一个非常完整的答案： http://mindprod.com/jgloss/runerrormessages.html#NOCLASSDEFFOUNDERROR

为什么我得到NoClassDefFoundError？

3 个答案: