JAVA功能代码-自定义类加载器加载不同版本的jar

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.net.URLClassLoader;
import java.net.URLStreamHandlerFactory;

public class CustomClassLoad extends URLClassLoader {

    public CustomClassLoad(){
        this(getSystemClassLoader());
    }
    public CustomClassLoad(ClassLoader parent) {
        super(new URL[] {}, null);
    }
    public void addURL(URL... urls) {
        if (urls != null) {
            for (URL url : urls) {
                super.addURL(url);
            }
        }
    }

    public void addFile(File... files) throws IOException {
        if (files != null) {
            for (File file : files) {
                if (file != null) {
                    super.addURL(file.toURI().toURL());
                }
            }
        }
    }
}