关于张孝祥老师高新技术ClassLoader类加载器部分的问题 - 黑马程序员技术交流社区

package study.day2;
import java.io.*;
import com.sun.beans.finder.ClassFinder;
public class MyClassLoader extends ClassLoader{
/**
* @param args
*/
public static void main(String[] args) throws Exception {
String srcPath = args[0];
String destDir = args[1];
FileInputStream fis = new FileInputStream(srcPath);
String destFileName = srcPath.substring(srcPath.lastIndexOf('\\'));
String destPath = destDir+destFileName;
FileOutputStream fos = new FileOutputStream(destPath);
cypher(fis,fos);
fis.close();
fos.close();
}
//加密方法
public static void cypher(InputStream fis, OutputStream fos) throws Exception {
int b = -1;
while((b=fis.read())!=-1){
fos.write(b ^ 0xff);
}
}
private String classDir;
@Override
protected Class<?> findClass(String name) throws ClassNotFoundException {
String classFileName = classDir+"\\"+name.substring(name.lastIndexOf('.')+1)+".class";
try {
System.out.println("It's MyClassLoader.");
FileInputStream fis = new FileInputStream(classFileName);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
cypher(fis,bos);
byte[] bys = bos.toByteArray();
return defineClass(null, bys, 0,bys.length);
}
catch (Exception e) {
e.printStackTrace();
}
return super.findClass(name);
}
public MyClassLoader(String classDir){
this.classDir = classDir;
}
}

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package study.day2;
import java.util.Date;
public class ClassLoderTest {
/**
* @param args
*/
public static void main(String[] args) throws Exception {
/*
System.out.println(ClassLoderTest.class.getClassLoader().getClass().getName());
System.out.println(System.class.getClassLoader());
ClassLoader loader = ClassLoader.class.getClassLoader();
while(loader!=null){
System.out.println(loader.getClass().getName());
loader = loader.getParent();
}
System.out.println(loader);
//System.out.println(new ClassLoaderAttachment().toString());
*/
//问题在这里,看这里,看这里!!
Class clazz = new MyClassLoader("itcastlib").loadClass("study.day2.ClassLoaderAttachment");//这里我明明是获取的ClassLoaderAttachment的字节码?
Date dd = (Date) clazz.newInstance();//但是这里却要用ClassLoaderAttachment的父类来引用和强转,不明白其中的道理,求大家帮助
System.out.println(dd);
}
}

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