用defineClass报错问题求教

cllncjh 2013-02-28 02:33:58

E:Plug.jar 是一个单独的Plug.class （没上层包）打的jar

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class CompilingClassLoader extends ClassLoader {
public Class getClas(String filename,String classname) throws IOException {
File file = new File(filename);
try
{ System.out.println("be to the Cload");
System.out.println("classname:"+classname);
Class ctmp = this.findLoadedClass(classname);
System.out.println(ctmp.getName()+" is load");
System.out.println("over!!");
return ctmp;
}
catch(Exception exception)
{
System.out.println("memory is null");
}
long len = file.length();
byte[] raw = new byte[(int)len];
FileInputStream fis = new FileInputStream(file);
int r = fis.read(raw);
if(r!=len) throw new IOException ("Cat not read all"+r+"!="+len);
fis.close();
return defineClass("classname",raw,0,raw.length);
}

public static void main(String[] args) throws IOException {
String s = "E:/Plug.jar";
File file = new File(s);
CompilingClassLoader ccl = new CompilingClassLoader();
Class clas = ccl.getClas(s,"Plug.class");
}

}

Exception in thread "main" java.lang.ClassFormatError: Incompatible magic value 1347093252 in class file classname
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.lang.ClassLoader.defineClass(ClassLoader.java:466)
at CompilingClassLoader.getClas(CompilingClassLoader.java:28)
at CompilingClassLoader.main(CompilingClassLoader.java:35)

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