java如何远程加载class文件

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import ch.ethz.ssh2.Connection;
import ch.ethz.ssh2.SFTPInputStream;
import ch.ethz.ssh2.SFTPv3Client;


public class Fs{
	public static void main(String[] args) throws Exception {
		OwnClassLoader ocl = new OwnClassLoader();
		String ip,user,password;
		ip = "120.34.168.80";//自己的远程ip
		user = "root";//username
		password = "123456";//password
		ocl.login(ip, user, password);
		Object obj = ocl.loadeOthClass("/opt/4/tt.class");//class文件路径
				
		System.out.println(obj);
		Class c = obj.getClass();
		Field f = c.getDeclaredField("age");
		f.setAccessible(true);
		System.out.println("age:"+f.get(obj));
	}
}
//自定义类加载器
class OwnClassLoader extends ClassLoader{
	private Connection conn = null;
	//初始化链接
	public  Connection login(String ip,String user,String password){
		Connection conn = null;
		try {
			//也可以new Connection(ip, port)创建对象,默认22
			conn = new Connection(ip);
			//连接远程服务
			conn.connect();
			//使用用户名和密码登录
			conn.authenticateWithPassword(user, password);
			this.conn  = conn;
	        return conn;
		} catch (IOException e) {   
			e.printStackTrace();
	  }
	  return null;
	}
	//返回远程实例
	public Object loadeOthClass(String url) throws Exception{
		if(null==conn)
			throw new Exception("请初始化链接");
		SFTPv3Client sc = new SFTPv3Client(conn);//创建ssh客户端连接
		InputStream is = new SFTPInputStream(sc.openFileRO(url));//创建输入流
		byte[] b = this.readClassFile(is);
		Class<?> c = super.defineClass(b, 0, b.length);//定义class
		return c.newInstance();//创建实例
	}
	//读取远程class文件
	private  byte[] readClassFile(InputStream is){
		byte[] b = new byte[1024];
		int len;
		ByteArrayOutputStream bos = null;
		try {
			bos = new ByteArrayOutputStream();//内存流输出
			while((len=is.read(b))!=-1){
				bos.write(b, 0, len);
			}
			b = bos.toByteArray();
		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally{
			try {
				if(is!=null)
					is.close();
				if(bos!=null)
					bos.close();
			} catch (Exception e2) {
				// TODO: handle exception
			}		
		}	
		return b;	
	}	
}