NoClassDefFoundError 静态字段

Question

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
    String reqURI = req.getRequestURI();
    reqURI = reqURI.replace(req.getContextPath(), "");
    try {
        ServiceFactory factory = ServiceFactory.getInstance();
        Service service = factory.getService(reqURI);
        service.doPost(req, resp);
    } catch (Exception e ) {
        ROOT_LOGGER.error(e.getMessage(), e);
        throw new ServletException(e);
    }
}

当我尝试获取 ServiceFactory 实例时，出现 NoClassDefFoundError。

它仅在部署应用程序后发生。如果我通过 IntelliJ 启动它，不会发生任何错误。

有什么问题吗？

public class ServiceFactory {
    private static final Map<String, Service> SERVICE_MAP = new HashMap<>();
    private static final ServiceFactory SERVICE_FACTORY = new ServiceFactory();

private ServiceFactory() {
        init();
    }

    private static void init() {
        SERVICE_MAP.put(LOGIN_PAGE_URI, new LoginService());
        SERVICE_MAP.put(LOGOUT_PAGE_URI, new LogoutService());
        SERVICE_MAP.put(SWITCH_LANGUAGE_URI, new SwitchLanguageService());
        SERVICE_MAP.put(USERS_PAGE_URI, new AllUsersService());
        SERVICE_MAP.put(REGISTRATION_PAGE_URI, new RegistrationService());
        SERVICE_MAP.put(DELETE_USER_PAGE_URI, new DeleteUserService());
        SERVICE_MAP.put(NEW_DOCUMENT_PAGE_URI, new NewDocumentService());
        SERVICE_MAP.put(GET_FORM_AJAX_PAGE_URI, new GetFormAJAX());
    }

    public static ServiceFactory getInstance() {
        return SERVICE_FACTORY;
    }

    public Service getService(String request) {
        return SERVICE_MAP.get(request);
    }

Answer 1

根据您提供的信息，您可能没有将导致 NoClassDefFoundError 的库包含到您的 class-path

java -cp <add-jar-paths-with-file-separator> <class-to-run> <arguments>

例如

java -cp lib/the-jar-you-are-missing.jar;myapp.jar com.mypackage.MyClassWithMain arg1

对于linux替换;字符 :

如果您的库有固定路径，您还可以将路径添加到 MANIFEST.MF

Manifest-Version: 1.0
...
Main-Class: com.mypackage.MyClassWithMain
Class-Path: lib/the-jar-you-are-missing.jar

https://docs.oracle.com/javase/7/docs/technotes/tools/windows/classpath.html

Intellij 不会自动为您执行此操作。可能有办法做到这一点，但不幸的是我不知道答案。

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