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  • java 类处理工具

    public class ClassUtils {
    
        private static final Logger LOGGER  = LoggerFactory.getLogger(ClassUtils.class);
    
        /**
         * 返回某个父类底下所有的实现类
         */public static List<Class> getSubClassesByParentClass(Class parentClass) {
    
            List<Class> returnClassList = new ArrayList<Class>();
    
            String packageName = parentClass.getPackage().getName();
            try {
                List<Class> allClass = getClassesByPackageName(packageName);
                for (int i = 0; i < allClass.size(); i++) {
                    if (parentClass.isAssignableFrom(allClass.get(i))) {
                        if (!parentClass.equals(allClass.get(i))) {
                            returnClassList.add(allClass.get(i));
                        }
                    }
                }
            } catch (Exception e) {
                LOGGER.error(e.getMessage(), e);
            }
            return returnClassList;
        }
    
        /**
         * 从一个包中查找出所有类,在jar包中不能查找
         * 
         * @param packageName
         * @return
         * @throws IOException
         * @throws ClassNotFoundException
         */
        public static List<Class> getClassesByPackageName(String packageName)
                throws IOException, ClassNotFoundException {
            ClassLoader classLoader = Thread.currentThread()
                    .getContextClassLoader();
            String path = packageName.replace('.', '/');
            Enumeration<URL> resources = classLoader.getResources(path);
            List<File> dirs = new ArrayList<File>();
            while (resources.hasMoreElements()) {
                URL resource = resources.nextElement();
                dirs.add(new File(resource.getFile()));
            }
            ArrayList<Class> classes = new ArrayList<Class>();
            for (File directory : dirs) {
                classes.addAll(findClasses(directory, packageName));
            }
            return classes;
        }
    
        /**
         * 
         * @param directory
         * @param packageName
         * @return
         * @throws ClassNotFoundException
         */
        public static List<Class> findClasses(File directory, String packageName)
                throws ClassNotFoundException {
            List<Class> classes = new ArrayList<Class>();
            if (!directory.exists()) {
                return classes;
            }
            File[] files = directory.listFiles();
            for (File file : files) {
                if (file.isDirectory()) {
                    assert !file.getName().contains(".");
                    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;
        }
    
        /**
         * 对Map类型数据按Key排序
         * 
         * @param map
         */public static List sort(Map map) {
            List list = new ArrayList(map.keySet());
            Collections.sort(list, new Comparator() {
                public int compare(Object a, Object b) {
                    return a.toString().toLowerCase().compareTo(
                            b.toString().toLowerCase());
                }
            });
            return list;
        }
    }
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  • 原文地址:https://www.cnblogs.com/rubekid/p/5336404.html
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