字节码加密（三）jar包解密后删除

在字节码加密（一）jar包加密https://www.cnblogs.com/silyvin/articles/11767818.html中

删除jar包是用delOnExit操作，但实际上是任务型的项目，跑完加密jar包的任务时，我们的jvm不会关闭，那解密的jar包就泄露了

因此我们要把jar包删除的操作放在类加载器finalize时

 

        Thread.sleep(5000);

        myUrlClassLoader = null;
        System.gc();

        Thread.sleep(5000);
    }

    private static class MyUrlClassLoader {

        URL [] murls;

        private URLClassLoader urlClassLoader;

        private static Coder coder = new Use3DES();

        public MyUrlClassLoader(URL[] urls) {
            URL [] urls1 = decode(urls);
            urlClassLoader = new URLClassLoader(urls1);
         //   delUrls(urls1);
            murls = urls1;
        }

        @Override
        protected void finalize() throws Throwable {
            System.out.println("回收decJar类加载器");
            for(URL url : murls) {
                File file = new File(url.getFile());
                file.delete();
            }
            super.finalize();
        }

        @Deprecated
        private static void delUrls(URL[] urls) {
            for(URL url : urls) {
                File file = new File(url.getFile());
                file.deleteOnExit();
            }
        }

        private static URL[] decode(URL [] urls) {
            URL[] outUrls = new URL[urls.length];
            for(int i=0; i<outUrls.length; ++i) {
                URL url = urls[i];

                String sin = url.getFile();
                String sout = sin + ".dec.jar";
                coder.decode(sin, sout);

                try {
                    outUrls[i] = new URL("file:" + sout);
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                }
            }
            return outUrls;
        }

        public Class<?> loadClass(String name) throws ClassNotFoundException {
            return urlClassLoader.loadClass(name);
        }

        public ClassLoader getParent() {
            return urlClassLoader.getParent();
        }
    }
}

 

parent:--sun.misc.Launcher$AppClassLoader@119d7047
C:--java.net.URLClassLoader@71be98f5
子 C 加载
父 D 加载
子 E 加载
回收decJar类加载器。 5秒后打印