Java中的自定义类加载器

是否可以在java中创建自己的自定义类加载器。 如果是那么请指导我。 我想在类文件中进行更改而不是类混淆，这样就无法通过任何工具进行反转

Answer 1

您可以使用一些混淆工具，如ProGuard。

自编写的ClassLoader必须放在标准的.class文件中，JVM可以加载它。 然后你安全装载机可以进行逆向工程。

不要自己动手。 在不知道加密算法的情况下编写“安全”代码将导致容易出错的不安全代码

Answer 2

import java.io.BufferedInputStream; import java.io.ByteArrayOutputStream; import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.util.HashMap; import java.util.Map; /** * * Simple custom class loader implementation * */ public class CustomClassLoader extends ClassLoader { /** * The HashMap where the classes will be cached */ private Map> classes = new HashMap>(); @Override public String toString() { return CustomClassLoader.class.getName(); } @Override protected Class findClass(String name) throws ClassNotFoundException { if (classes.containsKey(name)) { return classes.get(name); } byte[] classData; try { classData = loadClassData(name); } catch (IOException e) { throw new ClassNotFoundException("Class [" + name + "] could not be found", e); } Class c = defineClass(name, classData, 0, classData.length); resolveClass(c); classes.put(name, c); return c; } /** * Load the class file into byte array * * @param name * The name of the class eg com.codeslices.test.TestClass} * @return The class file as byte array * @throws IOException */ private byte[] loadClassData(String name) throws IOException { BufferedInputStream in = new BufferedInputStream( ClassLoader.getSystemResourceAsStream(name.replace(".", "/") + ".class")); ByteArrayOutputStream out = new ByteArrayOutputStream(); int i; while ((i = in.read()) != -1) { out.write(i); } in.close(); byte[] classData = out.toByteArray(); out.close(); return classData; } /** * Simple usage of the CustomClassLoader implementation * * @param args * @throws ClassNotFoundException * @throws IllegalAccessException * @throws InstantiationException * @throws SecurityException * @throws NoSuchMethodException * @throws InvocationTargetException * @throws IllegalArgumentException */ public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException, NoSuchMethodException, SecurityException, IllegalArgumentException, InvocationTargetException { CustomClassLoader loader = new CustomClassLoader(); // This class should be in your application class path Class c = loader.findClass("net.codeslices.test.TestClass"); Object o = c.newInstance(); Method m = c.getMethod("toString"); System.out.println(m.invoke(o)); } }