package Jiami;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;

class MyClassLoader extends ClassLoader
{
public static void main(String[] args) throws Exception
{
  String srcPath = args[0];
  String destDir = args[1];//目标的目录
  FileInputStream fis = new FileInputStream(srcPath);//在这里，如果用绝对路径可以直接用，用相对路径需要计算，为了方便这里用了相对路径（在工程下面）
  System.out.println(srcPath);
  String destFileName = srcPath.substring(srcPath.lastIndexOf("\\")+1);//目标文件名
  System.out.println(destFileName);
  String destPath = destDir +"\\"+ destFileName;
  System.out.println(destPath);
  FileOutputStream fos = new FileOutputStream(destPath);
  cypher(fis,fos);
  fis.close();
  fos.close();

}
private static void cypher(InputStream ips,OutputStream ops)throws Exception{

int b= -1;
while((b = ips.read())!=-1)
  {
   ops.write(b^0xff);
  }
}
private String classDir;

@Override

protected Class<?> findClass(String name) throws ClassNotFoundException {
  // TODO Auto-generated method stub

  System.out.println("name is"+name);
  String classFileName = classDir + "\\"+name +".class";
  System.out.println("classFileName is"+classFileName);
  try {
   FileInputStream fis = new FileInputStream(classFileName);
   ByteArrayOutputStream bos = new ByteArrayOutputStream();
   
   cypher(fis,bos);
   fis.close();
   byte[]  bytes = bos.toByteArray();
   return defineClass(bytes,0,bytes.length);
  } catch (Exception e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  return null;
}
public MyClassLoader(){
  
}
public MyClassLoader(String classDir){
  this.classDir = classDir;
}

}

------------------------------------------------------------------------
/**
*
*/
package Jiami;
import java.util.Date;
/**
* @author Administrator
*
*/
public class ClassLoaderTest {
/**
  * @param args
  * @throws Exception
  */
public static void main(String[] args) throws Exception {
  // TODO Auto-generated method stub
  System.out.println(ClassLoaderTest.class.getClassLoader().getClass().getName());
  
  System.out.println(System.class.getClassLoader());
  
  ClassLoader loader = ClassLoaderTest.class.getClassLoader();
  while(loader !=null){
   System.out.println(loader.getClass().getName());
   loader = loader.getParent();
  }
  System.out.println(loader);
  
  //System.out.println(new ClassLoaderAttachment().toString());
  Class clazz = new MyClassLoader("itcastlib").loadClass("ClassLoaderAttachment");
  Date d1 = (Date)clazz.newInstance();
  System.out.println(d1);
}
}
------------------------------------------------------------------------------------------------
执行结果报错：
sun.misc.Launcher$AppClassLoader
null
sun.misc.Launcher$AppClassLoader
sun.misc.Launcher$ExtClassLoader
null
Exception in thread "main" java.lang.NoClassDefFoundError: ClassLoaderAttachment (wrong name: Jiami/ClassLoaderAttachment)
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:792)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
at java.lang.ClassLoader.loadClass(ClassLoader.java:411)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at Jiami.ClassLoaderTest.main(ClassLoaderTest.java:32)

{:soso_e176:}
亲，请问下问题是否解决？
如果已解决请及时将未解决改为已解决
如果未解决请回帖追问
三天未回复的将视为已解决
详情参考：如何更改分类

保持队形，谢谢合作

{:soso_e181:}

刚才测试了一下你写的程序可以运行,应用是你传的参数出了问题,以下是我帮你测试时传入的参数你可以看一下:没有报错信息, AutoBox.class可以正常加密.
String srcPath = "E:\\workspace\\javaenhance\\bin\\cn\\itcast\\day1\\AutoBox.class";
String destDir = "itcastlib";