com.janetfilter.core.plugin.PluginClassLoader Maven / Gradle / Ivy
The newest version!
package com.janetfilter.core.plugin;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.jar.JarFile;
import java.util.zip.ZipEntry;
public final class PluginClassLoader extends ClassLoader {
private final JarFile jarFile;
public PluginClassLoader(JarFile jarFile) {
this.jarFile = jarFile;
}
@Override
public Class findClass(String name) throws ClassNotFoundException {
byte[] bytes = loadClassFromFile(name);
return defineClass(name, bytes, 0, bytes.length);
}
private byte[] loadClassFromFile(String fileName) throws ClassNotFoundException {
String classFile = fileName.replace('.', '/') + ".class";
ZipEntry entry = jarFile.getEntry(classFile);
if (null == entry) {
throw new ClassNotFoundException("Class not found: " + fileName);
}
int length;
byte[] buffer = new byte[1024];
ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
try (InputStream is = jarFile.getInputStream(entry)) {
while (-1 != (length = is.read(buffer))) {
byteStream.write(buffer, 0, length);
}
} catch (IOException e) {
throw new ClassNotFoundException("Can't access class: " + fileName, e);
}
return byteStream.toByteArray();
}
}