我已经为 rmi 编程了一段时间,大约一个月后,我仍然陷入了一个棘手的问题。我想将一个序列化对象从服务器发送到客户端,并且我希望客户端从服务器代码库下载该对象的类。如果在客户端的类路径中没有对象的类,我无法让它工作。这是我一直在做的事情:
我有一个ClientLoader
要求。还应该下载类ClientPlayer
AuthServer
ClientLoader
ClientPlayer
加载它。
这是身份验证服务器,它应该创建一个对象ClientPlayer
(或ClientAdmin
)并将其返回给ClientLoader
. (为简洁起见,我省略了接口;无论如何AlfaBetaInt
意味着Beta
实现它并Alfa
使用它)
public class AuthServer extends UnicastRemoteObject implements LoaderAuthInt{
private static MasterServer master;
public AuthServer() throws RemoteException{
super();
}
public Runnable login(String username, String password) throws RemoteException{
System.out.println("Requested login with username '" + username + "' and password '" + password + "'");
if(password.equals("admin"))
return (Runnable)(new ClientAdmin());
else
return (Runnable)(new ClientPlayer(username, (PlayerMasterInt)master));
}
public static void main(String[] args){
if(System.getSecurityManager() == null)
System.setSecurityManager(new RMISecurityManager());
String port = args[0];
System.out.println("Current codebase:" + System.getProperty("java.rmi.server.codebase"));
try{
master = new MasterServer();//create master server
System.out.println("MasterServer creato.");
AuthServer auth = new AuthServer();//create auth server
System.out.println("AuthServer created.");
Naming.rebind("//:" + port + "/authServer", (LoaderAuthInt)auth);//rebind auth server
System.out.println("AuthServer rebinded.");
}catch(Exception e){
System.err.println(e);
System.exit(1);
}
}
}
这ClientLoader
应该从服务器下载ClientPlayer
(对象和类)并运行它。
public class ClientLoader{
public static void main(String[] args){
if(System.getSecurityManager() == null)
System.setSecurityManager(new RMISecurityManager());
Console console = System.console();
String host = args[0];
try{
//check to see if Server is registered in rmiregistry
String[] lista = Naming.list("//" + host );
for( int i = 0; i < lista.length; i = i+1)
System.out.println(lista[i]);
//look up the client
LoaderAuthInt authServer = (LoaderAuthInt)Naming.lookup("//" + host + "/authServer");
System.out.println("Lookup succesful.");
if( authServer != null)
System.out.println("authServer != null.");
//RUN THE CLIENT!
Runnable client = authServer.login(console.readLine("Username: "), new String(console.readPassword("Password: ")));
if(client == null)
System.err.println("Login not valid");
else
client.run();
System.out.println("Bye bye");
}catch(Exception e){
System.err.println(e);
System.exit(1);
}
}
}
这是应该从 发送到 的AuthServer
对象ClientLoader
:
public class ClientPlayer implements Runnable, Serializable, GamePlayerInt{
private String username;
private PlayerMasterInt master;
public ClientPlayer(String username, PlayerMasterInt master){
this.username = username;
this.master = master;
}
public void run(){
Console console = System.console();
System.out.println("I'm a succesfully authenticated ClientPlayer!");
}catch(RemoteException e){
System.err.println(e);
System.exit(1);
}
}
}
public String getUsername() throws RemoteException{
return username;
}
}
这是启动服务器的脚本:请注意,我确实指定了代码库并将属性设置useCodeBaseOnly
为false
if [ "$1" == "" -o "$2" == "" ]; then
echo "usage: $0 <ip> <port number>"
else
java -Djava.rmi.server.codebase=http://$1:8000/ \
-Djava.rmi.server.hostname=$1 \
-Djava.security.policy=policy \
-Djava.rmi.server.useCodebaseOnly=false \
card.AuthServer $2
fi
这是我启动的方式ClientLoader
:再次,我设置了代码库并useCodeBaseOnly
if [ "$1" == "" -o "$2" == "" ]; then
echo "usage: $0 <ip> <port>"
else
java -Djava.security.policy=policy \
-Djava.rmi.server.useCodebaseOnly=true \
-Djava.rmi.server.codebase=http://$1:8000/ \
card.ClientLoader "$1:$2"
fi
服务器运行良好;我在端口 8000 有一个 http 服务器,在端口 2378 有一个 rmiregistry。客户端加载程序运行......准很好:list()
rmiregistry 上的方法显示绑定的服务器,服务器的查找工作,我可以从服务器,但是当我运行它时,我得到了ClassNotFoundException
:
java.rmi.UnmarshalException: error unmarshalling return; nested exception is:
java.lang.ClassNotFoundException: card.ClientPlayer (no security manager: RMI class loader disabled)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:196)
at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:194)
at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:148)
at com.sun.proxy.$Proxy0.login(Unknown Source)
at card.ClientLoader.main(ClientLoader.java:26)
Caused by: java.lang.ClassNotFoundException: card.ClientPlayer (no security manager: RMI class loader disabled)
at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:395)
at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:185)
at java.rmi.server.RMIClassLoader$2.loadClass(RMIClassLoader.java:637)
at java.rmi.server.RMIClassLoader.loadClass(RMIClassLoader.java:264)
at sun.rmi.server.MarshalInputStream.resolveClass(MarshalInputStream.java:222)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1610)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1515)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1769)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1348)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
at sun.rmi.server.UnicastRef.unmarshalValue(UnicastRef.java:324)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:173)
... 4 more
我怀疑ClientLoader
没有使用正确的代码库......非常感谢任何帮助!
编辑:我-Djava.security.manager
按照建议添加到客户端启动脚本中......但这会导致这些安全异常:
Exception in thread "main" java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "writeFileDescriptor")
at java.security.AccessControlContext.checkPermission(AccessControlContext.java:372)
at java.security.AccessController.checkPermission(AccessController.java:559)
at java.lang.SecurityManager.checkPermission(SecurityManager.java:549)
at java.lang.SecurityManager.checkWrite(SecurityManager.java:954)
at java.io.FileOutputStream.<init>(FileOutputStream.java:244)
at java.io.Console.<init>(Console.java:566)
at java.io.Console.<init>(Console.java:92)
at java.io.Console$2.console(Console.java:540)
at java.lang.System.console(System.java:211)
at card.ClientLoader.main(ClientLoader.java:14)
请注意,我确实有策略文件(授予AllPermission
)!该选项是否会-Djava.security.manager
更改策略配置?
编辑:策略文件中有错字。[我可以讨厌 java rmi 吗?] 所以,回到 . ClassNotFoundException
,虽然风格略有不同:
java.rmi.UnmarshalException: error unmarshalling return; nested exception is:
java.lang.ClassNotFoundException: card.ClientPlayer
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:196)
at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:194)
at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:148)
at com.sun.proxy.$Proxy0.login(Unknown Source)
at card.ClientLoader.main(ClientLoader.java:25)
Caused by: java.lang.ClassNotFoundException: card.ClientPlayer
at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.rmi.server.LoaderHandler$Loader.loadClass(LoaderHandler.java:1208)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:270)
at sun.rmi.server.LoaderHandler.loadClassForName(LoaderHandler.java:1221)
at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:454)
at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:185)
at java.rmi.server.RMIClassLoader$2.loadClass(RMIClassLoader.java:637)
at java.rmi.server.RMIClassLoader.loadClass(RMIClassLoader.java:264)
at sun.rmi.server.MarshalInputStream.resolveClass(MarshalInputStream.java:222)
at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1610)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1515)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1769)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1348)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
at sun.rmi.server.UnicastRef.unmarshalValue(UnicastRef.java:324)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:173)
... 4 more
任何想法?我真的很难让这个工作......