客户端程序没有命中 RMI 中的服务器程序

Question

下面是实现RMI的sn-ps

以下是我的服务器类

package com.queryExecutor.actionclass;   
import java.rmi.Naming;   
import java.rmi.RemoteException;   
import java.rmi.registry.LocateRegistry;   
import java.rmi.server.UnicastRemoteObject;   
import java.util.concurrent.ExecutorService;   
import java.util.concurrent.Executors;   

public class ExecutorServer extends UnicastRemoteObject implements executorInterface   
{   
public ExecutorServer()throws RemoteException   
{   
System.out.println("Server is in listening mode");   
}   
public void executeJob(String req_id,String usrname,String pwd,String driver,String url)throws RemoteException     
{   
    System.out.println("Inside executeJob...");   
    acQueryExecutor a=new acQueryExecutor(req_id,usrname,pwd,driver,url);   

    ExecutorService threadExecutor = Executors.newCachedThreadPool();   

    threadExecutor.execute(a); // start task1   

    threadExecutor.shutdown(); // shutdown worker threads   

}      
public void killJob(String req_id)throws RemoteException{}   
public int getJobStatus(String req_id)throws RemoteException{return 1;}   
public void restart(String req_id)throws RemoteException{}   


public static void main(String arg[])   
{   
try{   
    //Registry registry = LocateRegistry.getRegistry("10.155.1.159",1099);    
    LocateRegistry.createRegistry(2005);   
ExecutorServer p=new ExecutorServer();   
Naming.rebind("//127.0.0.1:2005/exec",p);   
}catch(Exception e)   
{   
System.out.println("Exception occurred : "+e.getMessage());   
}   
}   
@Override  
public void executeJob(String req_id, String usrname, String pwd)   
        throws RemoteException {   
    // TODO Auto-generated method stub   
       System.out.println("Inside executeJob...");
acQueryExecutor a=new acQueryExecutor(req_id,usrname,pwd,"driver","url");

ExecutorService threadExecutor = Executors.newCachedThreadPool();
threadExecutor.execute(a); // start task1
threadExecutor.shutdown(); // shutdown worker threads
}   
}  

界面

package com.queryExecutor.actionclass;   
import java.rmi.Remote;   
import java.rmi.RemoteException;   

public interface executorInterface extends Remote   
{   
public void executeJob(String req_id,String usrname,String pwd)throws RemoteException;   
public void killJob(String req_id)throws RemoteException;   
public int getJobStatus(String req_id)throws RemoteException;   
public void restart(String req_id)throws RemoteException;   
}  
package com.queryExecutor.actionclass;
import java.rmi.Remote;
import java.rmi.RemoteException;

public interface executorInterface extends Remote
{
public void executeJob(String req_id,String usrname,String pwd)throws RemoteException;
public void killJob(String req_id)throws RemoteException;
public int getJobStatus(String req_id)throws RemoteException;
public void restart(String req_id)throws RemoteException;
} 

客户

package com.queryExecutor.actionclass;   
import java.rmi.Naming;   

    public class testClient {   
    public static void  main(String args[])   
    {   
    try{   

        executorInterface p=(executorInterface)Naming.lookup("//127.0.0.1:2005/exec");   

    p.executeJob("1", "abc", "abc");   


    }   
    catch(Exception e)   
    {   
    System.out.println("Exception occurred : "+e.getMessage());   
    }   
    }   
    }  

当我运行客户端代码时，我没有得到任何输出，而是在 Eclipse 控制台标题中它写入的 javaw.exe 终止。 我的问题是为什么我的客户端程序没有访问服务器。

Answer 1

1. 您需要将LocateRegistry.createRegistry() 的结果存储在不会被垃圾回收的地方。否则将被垃圾回收 => 没有注册表 => Naming.lookup() 失败 => 客户端静默退出，因为您通过将异常打印到 javaw.exe 进程的 System.out 来处理异常没有这种东西。

2. 当调用Naming.bind() 或Naming.rebind() 时，使用“localhost”以外的任何主机名都没有多大意义。如果主机名不是本地的，它无论如何都会失败，所以你只是在服务器代码中添加了一个额外的无意义的配置噩梦。将其设为“localhost”，它将在任何地方运行。

3. 你的executeJob() 方法完全是疯了。它创建一个 Executor，调度一个作业，然后关闭 Executor：所以 Executor 永远不能做线程池；所以这基本上是浪费时间。您也可以只生成一个线程来执行任务；但是由于 RMI 已经是多线程的，您也可以自己执行任务。失去这一切。