rest - 使用 @Path 注释从包中加载所有类

Question

我试过寻找答案，但没有找到任何答案。我想利用一个现有的 JAR，它在包的几个部分下有几个类。这些类具有 JAX-RS 注释，因此我希望使用 CXF 来加载所有这些类并将它们连接为 CXF 端点。

CXF 是否可以将其指向一个包并将所有类连接到端点？

Answer 1

据我所知CXF，不会从一些jar带有注释的类中加载一些类。您需要手动执行此操作。例如，要获取使用特定注释注释的类，您可以使用以下命令：

public class AnnotationHandler {

    private static final Logger LOGGER = LoggerFactory.getLogger(AnnotationHandler.class);

    /**
     * Scans all classes accessible from the context class loader which belong to the given package and sub packages.
     *
     * @param packageName the base package
     * @return The classes
     * @throws ClassNotFoundException if class not found exception occurs
     * @throws IOException            if IO error occurs
     */
    public Iterable<Class> getClasses(String packageName)
            throws ClassNotFoundException, IOException {
        ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        String path = packageName.replace('.', '/');
        Enumeration<URL> resources = classLoader.getResources(path);
        LinkedList<File> dirs = new LinkedList<File>();
        while (resources.hasMoreElements()) {
            URL resource = resources.nextElement();
            dirs.add(new File(resource.getFile()));
        }
        LinkedList<Class> classes = new LinkedList<Class>();
        for (File directory : dirs) {
            classes.addAll(findClasses(directory, packageName));
        }
        return classes;
    }

    /**
     * Recursive method used to find all classes in a given directory and sub directories.
     *
     * @param directory   the base directory
     * @param packageName the package name for classes found inside the base directory
     * @return the classes
     * @throws ClassNotFoundException if class not found exception occurrs
     */
    private LinkedList<Class> findClasses(File directory, String packageName)
            throws ClassNotFoundException {
        LinkedList<Class> classes = new LinkedList<Class>();
        if (!directory.exists()) {
            return classes;
        }
        File[] files = directory.listFiles();
        if (files != null) {
            for (File file : files) {
                if (file.isDirectory()) {
                    classes.addAll(findClasses(file, packageName + "." + file.getName()));
                } else if (file.getName().endsWith(".class")) {
                    classes.add(Class.forName(
                            packageName + '.'
                                    + file.getName().substring(0, file.getName().length() - 6)));
                }
            }
        }
        return classes;
    }

    /**
     * Finds all classes annotated with passed annotation in provided package. Unchecked system exception might be
     * thrown if the class is not found or IO exception occurs.
     *
     * @param annotationClass annotation class
     * @param packageName     package name to search for annotated classes
     * @return list of annotated class with specified annotation
     */
    public LinkedList<Class> findAnnotatedClasses(Class annotationClass, String packageName) {
        LinkedList<Class> classes = new LinkedList<Class>();
        try {
            for (Class clazz : getClasses(packageName)) {
                if (clazz.isAnnotationPresent(annotationClass)) {
                    classes.add(clazz);
                }
            }
        } catch (ClassNotFoundException ex) {
            LOGGER.error("Class not found exception occurred.", ex);
            throw new SystemException("Class not found exception occurred.", ex);
        } catch (IOException ex) {
            LOGGER.error("IO exception occurred.", ex);
            throw new SystemException("IO exception occurred.", ex);
        }
        return classes;
    }

}

通过提供注解类和包名进行调用findAnnotatedClasses，您将获得一个使用指定注解注解的类列表。

然后你可以用这些类做任何你想做的事情。