目录

■java代码

■注意

■运行效果

■包的结构

---

=============

■java代码

package com.sxz.study.reflect;

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

public class Test {
	public static void main(String[] args) {

		// Search Target Class
		Class searchClass = com.sxz.study.classload.Parent.class;

		// Search Target Package Name
		String searchPackageName = "com.sxz.study";

		List<Class> subClasses = getSubClasses(searchClass, searchPackageName);
		System.out.println(" Result ========================================== Result");
		for (Class subClass : subClasses) {
			System.out.println(subClass.getName());
		}
	}

	/**
	 * 
	 * Get SubClass Search From Package
	 * 
	 * @param parentClass
	 * @param packageName
	 * @return
	 */
	public static List<Class> getSubClasses(Class parentClass, String packageName) {
		List<Class> subClasses = new ArrayList<>();
		try {

			System.out.println("========================================== Now Load Package Begin.");
			Package[] packages = Package.getPackages();
			for (Package pkg : packages) {
				System.out.println(pkg.getName());
			}
			System.out.println("========================================== Now Load Package End.");

			// Get Class from package.
			List<Class<?>> classes = getClasses(packageName);

			for (Class clazz : classes) {

				System.out.println(clazz.getTypeName());
				// Is SubClass ?
				if (parentClass.isAssignableFrom(clazz) && !clazz.equals(parentClass)) {
					subClasses.add(clazz);
				}
			}
		} catch (ClassNotFoundException ex) {
			ex.printStackTrace();
		}

		return subClasses;

	}

	/**
	 * 
	 * Get Class from package.
	 * 
	 * @param packageName
	 * @return
	 * @throws ClassNotFoundException
	 */
	public static List<Class<?>> getClasses(String packageName) throws ClassNotFoundException {
		ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
		String path = packageName.replace('.', '/');
		Enumeration<URL> resources;
		try {
			resources = classLoader.getResources(path);
		} catch (IOException e) {
			throw new ClassNotFoundException("Package not found", e);
		}
		List<File> dirs = new ArrayList<>();
		while (resources.hasMoreElements()) {
			URL resource = resources.nextElement();
			dirs.add(new File(resource.getFile()));
		}
		List<Class<?>> classes = new ArrayList<>();
		for (File directory : dirs) {
			classes.addAll(findClasses(directory, packageName));
		}
		return classes;
	}

	/**
	 * 
	 * @param directory
	 * @param packageName
	 * @return
	 * @throws ClassNotFoundException
	 */
	private static List<Class<?>> findClasses(File directory, String packageName) throws ClassNotFoundException {
		List<Class<?>> classes = new ArrayList<>();
		if (!directory.exists()) {
			return classes;
		}
		File[] files = directory.listFiles();
		for (File file : files) {
			if (file.isDirectory()) {
				assert !file.getName().contains(".");
				// 使用到了递归
				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;
	}

}

===

■注意

所有被扫描的类，都会被加载

■运行效果

========================================== Now Load Package Begin.
sun.reflect
java.util
sun.reflect.annotation
java.lang.annotation
java.nio
sun.nio
java.security.cert
java.util.zip
sun.launcher
sun.security.action
java.nio.file
com.sxz.study.reflect
java.nio.charset
sun.net.www
java.lang.ref
java.net
jdk.internal.util
sun.net.www.protocol.file
java.lang.invoke
sun.util.locale
sun.reflect.generics.repository
com.sxz.study.classload
sun.misc
java.lang.reflect
sun.net.util
java.security
sun.net.www.protocol.jar
java.util.concurrent
sun.io
java.util.concurrent.atomic
java.util.concurrent.locks
sun.util
java.lang
sun.nio.cs.ext
java.io
sun.reflect.misc
sun.nio.ch
java.util.jar
sun.nio.cs
java.util.function
java.nio.charset.spi
sun.security.util
sun.usagetracker
========================================== Now Load Package End.
父类--静态变量
父类--静态初始化块
子类--静态变量
子类--静态初始化块
Face--静态变量
Face--静态初始化块
Face--构造器
Person invoked
com.sxz.study.aes.AESUTil
com.sxz.study.aes.TestAES
com.sxz.study.alogrithm.TestAlogrithom2
com.sxz.study.aop.AspectTest
com.sxz.study.aop.MyAspect
com.sxz.study.classload.Child
com.sxz.study.classload.ClassLoadTest
com.sxz.study.classload.Face
com.sxz.study.classload.Parent
com.sxz.study.classload.Person$1
com.sxz.study.classload.Person
com.sxz.study.conf.AppConf
com.sxz.study.extend.Test
com.sxz.study.file.Test
com.sxz.study.file.Test2
com.sxz.study.http.HttpClientTest
com.sxz.study.json.TestBean
com.sxz.study.json.TestJson
com.sxz.study.jvm.Test$1
com.sxz.study.jvm.Test
com.sxz.study.messageDigest.MessageDigestTest
com.sxz.study.objectReflect.Person
com.sxz.study.objectReflect.Test
com.sxz.study.observer.ConcreteObserver
com.sxz.study.observer.ConcreteSubject
com.sxz.study.observer.Observer
com.sxz.study.observer.ObserverPatternExample
com.sxz.study.observer.Subject
com.sxz.study.process.TestProcess
com.sxz.study.reflect.Test
com.sxz.study.socket.Client
com.sxz.study.socket.Server
com.sxz.study.thread.ThreadStudy1$1
com.sxz.study.thread.ThreadStudy1
com.sxz.study.type.Test
 Result ========================================== Result
com.sxz.study.classload.Child
 

==

■包的结构

==

===