Question

我在官方网站（http://code.google.com/p/reflections/）上找到了此代码，但这不起作用（reflections.getSubTypesOf(requestedClass)返回空列表）

  new Reflections(new ConfigurationBuilder()
          .filterInputsBy(new FilterBuilder().include(FilterBuilder.prefix("my.project.prefix")))
          .setUrls(ClasspathHelper.forPackage("my.project.prefix"))
          .setScanners(new SubTypesScanner(),
                       new TypeAnnotationsScanner().filterResultsBy(filter),
                       new ResourcesScanner()));

这是我的代码

@SuppressWarnings({ "rawtypes", "unchecked" })
public Class<? extends ApplicationModuleAbst>
        getApplicationModuleAbstSubClass(
                ApplicationModuleAbst objInTheSamePckg, 
                Class<? extends ApplicationModuleAbst> requestedClass) {
     String pckName = objInTheSamePckg.getClass().getPackage().getName();
     Reflections reflections = new Reflections(new ConfigurationBuilder()
     .filterInputsBy(new FilterBuilder().include(FilterBuilder.prefix(pckName)))
     .setUrls(ClasspathHelper.forPackage(pckName))
     .setScanners(new SubTypesScanner(),
                  new ResourcesScanner()));
    Set<?> applicationModuleAbstSubTypeClasses = 
             reflections.getSubTypesOf(requestedClass);
    Class<? extends ApplicationModuleAbst> appModCls = null;
    if (applicationModuleAbstSubTypeClasses.size() == 1) {
        appModCls = (Class<? extends ApplicationModuleAbst>)
                applicationModuleAbstSubTypeClasses.iterator().next();
    } else {
        throw new RuntimeException("Exist more than one class that extend " + requestedClass.getName() + " in package " + requestedClass.getPackage().getName());
    }

    return appModCls;
}

有人知道问题出在哪里？

Answer 1

简单：它返回空集，因为包中没有类指定的任何子类。

Answer 2

您可以简单地使用它：

Reflections reflections = new Reflections("my.package.prefix")

并且可能还添加了jboss-vfs类型，如JbossIntegration wiki页面所示：

Vfs.addDefaultURLTypes(
    new Vfs.UrlType() {
        public boolean matches(URL url) {
            return url.getProtocol().equals("vfs");
        }

        public Vfs.Dir createDir(URL url) {
            VirtualFile content;
            try {
                content = (VirtualFile) url.openConnection().getContent();
            } catch (Throwable e) {
                throw new ReflectionsException("could not open url connection as VirtualFile [" + url + "]", e);
            }

            Vfs.Dir dir = null;
            try {
                dir = createDir(new java.io.File(content.getPhysicalFile().getParentFile(), content.getName()));
            } catch (IOException e) { /*continue*/ }
            if (dir == null) {
                try {
                    dir = createDir(content.getPhysicalFile());
                } catch (IOException e) { /*continue*/ }
            }
            return dir;
        }

        Vfs.Dir createDir(java.io.File file) {
            try {
                return file.exists() && file.canRead() ? file.isDirectory() ? new SystemDir(file) : new ZipDir(new JarFile(file)) : null;
            } catch (IOException e) {
                e.printStackTrace();
            }
            return null;
        }
    });

反思不起作用

2 个答案: