我创建了一个ClassLoader想要加载一个类,但是从文件中读取byte[]这不也能成功,但是在defineClass(name, classBytes, 0, classBytes.length);这步时会报java.lang.ClassFormatError: Incompatible magic value 1668047219 in class file resources/ClassTest异常,我试了好几次都出现这个问题,有人能帮我解决下吗?
调试欢乐多
class MyCLassLoader extends ClassLoader{
private int key;
public MyCLassLoader(int key){
this.key = key;
}
protected Class<?> findClass(String name){
byte[] classBytes = null;
try {
classBytes = loadClassBytes(name);
} catch (Exception e) {
e.printStackTrace();
}
Class<?> c = defineClass(name, classBytes, 0, classBytes.length);
if(c == null)
try {
throw new ClassNotFoundException(name);
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return c;
} private byte[] loadClassBytes(String name) throws Exception {
// TODO Auto-generated method stub
String cname = name.replace('.', '/') + ".MY";
FileInputStream in = null;
in = new FileInputStream(cname);
ByteArrayOutputStream butter = new ByteArrayOutputStream();
int ch;
while ( (ch = in.read()) != -1 ) {
ch = (byte)(ch-key);
butter.write(ch);
}
return butter.toByteArray();
}
}
public class ClassLoaderTest { /**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
MyCLassLoader mc = new MyCLassLoader(3);
Class<?> c = mc.findClass("src.ClassLoader.ClassTestEx");
}}
这个.MY后缀是一个.class文件通过key转换过来的,为什么还是会抛出java.lang.NoClassDefFoundError: src/ClassLoader/ClassTestEx (wrong name: ClassLoader/ClassTestEx)异常
我改了点,现在可以获取类了,但是拿到的类有点奇怪不能调用任何东西,连newInstance()也报错。。
java.lang.IllegalAccessException: Class ClassLoader.ClassLoaderTest can not access a member of class ClassLoader.ClassTestEx with modifiers ""