Dynamic Proxy 在 Java RMI 中的应用 学习疑问

Question

  Dynamic Proxy 在 Java RMI 中的应用 这篇文章google一搜，尽是转载
  
        请教各位RMI达人：
 这篇文章中的实例是否可实现，
在simpleserver中的
    URLClassLoader cl = new DynamicClassLoader(new URL[] { new
                      File("demo").toURL() });
demo文件内容是啥呢？
我这个地方运行时报错如下C:\code\proxy>start java -Djava.rmi.server.codebase=file:/c:/code/ SimpleServerC:\code\proxy>java -Djava.rmi.server.codebase=file:/c:/code/ SimpleServer
Exception in thread "main" java.lang.NoClassDefFoundError: SimpleServer
Caused by: java.lang.ClassNotFoundException: SimpleServer
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)

Answer 1

Caused by: java.lang.ClassNotFoundException: SimpleServer 
报错都给你说了,没有找到该类!

Answer 2

根据3楼进行的修正，但这回更奇怪，跟到这个simpleserver里面debug，就是到 UnicastRemoteObject.exportObject(server);
报错。
server一直是有内容的，高手指点啊[code=Java]
import java.lang.reflect.Proxy;
import java.io.*;
import java.net.*;
import java.rmi.*;
import java.rmi.server.*;
import java.rmi.registry.*;public class SimpleServer
{
    public static void main(String[] args)
    {
        try {
            // Create remote object
            URLClassLoader cl = new DynamicClassLoader(new URL[] { new
                      File("demo").toURL() });            Remote server = (Remote)cl.loadClass("SmallWorldImpl").newInstance();            // it should be DynamicRemoteStub
            System.out.println("StubObject is: " +
                RemoteObject.toStub((RemoteObject)server).getClass());            // add log Proxy to the remote object
            server = (Remote)Proxy.newProxyInstance(server.getClass().getClassLoader(),
                                                    new Class[] { SmallWorld.class },
                                                    new LogProxy(server));            // add performance Proxy to the remote object
            server = (Remote)Proxy.newProxyInstance(server.getClass().getClassLoader(),
                                                    new Class[] { SmallWorld.class },
                                                    new PerformanceProxy(server));            UnicastRemoteObject.exportObject(server);
            Registry reg = LocateRegistry.createRegistry(1099);
            reg.bind(SmallWorld.NAME, server);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
[code]C:\code\proxy>java -Djava.rmi.server.codebase=file:/c:/code/proxy/ SimpleServerStubObject is: class SmallWorldImpl_Stub
java.rmi.StubNotFoundException: Stub class not found: $Proxy0_Stub; nested excep
tion is:
        java.lang.ClassNotFoundException: $Proxy0_Stub
        at sun.rmi.server.Util.createStub(Unknown Source)
        at sun.rmi.server.Util.createProxy(Unknown Source)
        at sun.rmi.server.UnicastServerRef.exportObject(Unknown Source)
        at java.rmi.server.UnicastRemoteObject.exportObject(Unknown Source)
        at java.rmi.server.UnicastRemoteObject.exportObject(Unknown Source)
        at SimpleServer.main(SimpleServer.java:33)
Caused by: java.lang.ClassNotFoundException: $Proxy0_Stub
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Unknown Source)
        ... 6 more

Answer 3

所在目录内容如下
 C:\code\proxy 的目录2008-06-20  08:28    <DIR>          .
2008-06-20  08:28    <DIR>          ..
2008-06-20  09:54             5,080 proxy.zip
2008-06-20  09:52    <DIR>          client
2008-06-20  08:11               169 client.policy
2008-06-20  09:55             1,763 SmallWorldImpl_Stub.class
2008-06-20  12:02            19,322 testRandom.zip
2008-06-18  11:09             1,561 testRandom.class
2008-06-20  11:08             1,300 DynamicClassLoader.class
2008-06-20  09:35             1,169 DynamicRemoteStub.class
2008-06-20  09:30             1,250 DynamicStubHandler.class
2008-06-20  09:44               966 LogProxy.class
2008-06-20  09:49               998 PerformanceProxy.class
2008-06-20  09:49             2,281 SimpleServer.class
2008-06-20  09:25               280 SmallWorld.class
2008-06-20  09:25               831 SmallWorldImpl.class
2008-06-20  11:08             1,213 DynamicClassLoader.java
2008-06-20  09:35             1,038 DynamicRemoteStub.java
2008-06-20  09:30               903 DynamicStubHandler.java
2008-06-20  09:44               575 LogProxy.java
2008-06-20  09:49               597 PerformanceProxy.java
2008-06-20  09:49             1,543 SimpleServer.java
2008-06-20  09:25               225 SmallWorld.java
2008-06-20  09:25               465 SmallWorldImpl.java
2008-06-18  11:09               787 testRandom.java
              22 个文件         44,316 字节
               3 个目录  4,860,551,168 可用字节

Answer 4

我的这两篇文章可能会给你启示，你的类加载器找不到需要的类。
http://blog.csdn.net/sunyujia/archive/2008/06/08/2524105.aspx
http://blog.csdn.net/sunyujia/archive/2008/06/01/2500684.aspx

Answer 5

真是奇怪了，SmallWorldImpl_Stub.class明明就在目录file:/c:/code/proxy/ 下面，莫非变身之后他要的不是这个stub？

Answer 6

          URLClassLoader cl = new DynamicClassLoader(new URL[] { new 
                      File("demo").toURL() }); 
你是定义了，但是好像我没有看到你那里有用，下面的两个地方都应该用你定义的。

Answer 7

It is used here:(Remote server = (Remote)    cl     .loadClass("SmallWorldImpl").newInstance(); 

Answer 8

 URLClassLoader cl = new DynamicClassLoader(new URL[] { new 
                      File("demo").toURL() }); 

Answer 9

what is wrong with this code?