RMI（java.net.ConnectException：连接被拒绝：连接）

RMI(java.net.ConnectException: Connection refused: connect)

提问by user2644819

I am trying to run my server named SampleServer. I am using windows and this is what i did:

我正在尝试运行名为 SampleServer 的服务器。我正在使用 Windows，这就是我所做的：

in cmd:

在 cmd 中：

javaw rmiregistry 1099
cd C:\Users\Home\workspace\RMI\src
java -Djava.security.policy=policy SampleServer 1099

i get the following error:

我收到以下错误：

binding //localhost:1099/Sample
New instance of Sample created
Sample server failed:Connection refused to host: localhost; nested exception is:

        java.net.ConnectException: Connection refused: connect

I've tried using a different port # such as 4719 for rmiregistry but i receive the same error. I made sure that my firewall was disabled but the problem persist. I made sure that the port is not already being used. I really hope someone can help me.

我尝试使用不同的端口号，例如 4719 用于 rmiregistry，但我收到相同的错误。我确保我的防火墙已禁用，但问题仍然存在。我确保该端口尚未被使用。我真的希望有人能帮助我。

Picture of my desktop with folders of project, eclipse window and cmd open: http://s22.postimg.org/uq00qzslr/picyture.png

我的桌面图片，其中包含项目文件夹、eclipse 窗口和 cmd 打开：http: //s22.postimg.org/uq00qzslr/picyture.png

Code:

代码：

SampleServer:

示例服务器：

import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.RMISecurityManager;
import java.rmi.server.UnicastRemoteObject;

public class SampleServer {
    public static void main(String args[]) {
        if (args.length != 1) {
            System.err.println("usage: java SampleServer rmi_port");
            System.exit(1);
        }
        // Create and install a security manager
        if (System.getSecurityManager() == null)
            System.setSecurityManager(new RMISecurityManager());
        try {
            // first command-line argument is the port of the rmiregistry
            int port = Integer.parseInt(args[0]);
            String url = "//localhost:" + port + "/Sample";
            System.out.println("binding " + url);
            Naming.rebind(url, new Sample());
            // Naming.rebind("Sample", new Sample());
            System.out.println("server " + url + " is running...");
        }
        catch (Exception e) {
            System.out.println("Sample server failed:" + e.getMessage());
        }
    }
}

SampleClient:

示例客户端：

import java.rmi.Naming;
import java.rmi.RemoteException;

public class SampleClient  {
    public static void main(String args[]) {
        try {
            if (args.length < 3) {
                System.err.println("usage: java SampleClient host port string... \n");
                System.exit(1);
            }

            int port = Integer.parseInt(args[1]);
            String url = "//" + args[0] + ":" + port + "/Sample";
            System.out.println("looking up " + url);

            SampleInterface sample = (SampleInterface)Naming.lookup(url);

            // args[2] onward are the strings we want to reverse
            for (int i=2; i < args.length; ++i)
                // call the remote method and print the return
                System.out.println(sample.invert(args[i]));
        } catch(Exception e) {
            System.out.println("SampleClient exception: " + e);
        }
    }
}

SampleInterface:

示例界面：

import java.rmi.Remote;
import java.rmi.RemoteException;

public interface SampleInterface extends Remote {
    public String invert(String msg) throws RemoteException;
}

Sample:

样本：

import java.rmi.Remote;
import java.rmi.RemoteException;
import java.rmi.server.*;

// this is the class with remote methods

public class Sample
  extends UnicastRemoteObject
  implements SampleInterface {

    private int a;

    public Sample() throws RemoteException {
    System.out.println("New instance of Sample created");
    a = 1;
    }

    public String invert(String m) throws RemoteException {
        // return input message with characters reversed
        System.out.println("invert("+m+") a=" + a);
        return new StringBuffer(m).reverse().toString();
    }
}

policy:

政策：

grant {
    permission java.security.AllPermission;
};

回答by user207421

javaw rmiregistry 1099

javaw rmiregistry 1099

Stop right there. This is already wrong. 'rmiregistry' is an executable, not the name of a Java class you can execute with 'java' or 'javaw'. Just use 'rmiregistry'.

停在那儿。这已经是错误的了。'rmiregistry' 是一个可执行文件，而不是您可以使用 'java' 或 'javaw' 执行的 Java 类的名称。只需使用'rmiregistry'。

回答by Keerthivasan

This error occurs when there is no service running on the port, you are trying to connect. As said by EJP, rmiregistryis a tool which can be started by rmiregistry &in the background (JDK 7). I would recommend you that you check your firewall or connectivity issue with the port.

当端口上没有运行任何服务，您正在尝试连接时，会发生此错误。正如 EJP 所说，rmiregistry是一个可以rmiregistry &在后台启动的工具（JDK 7）。我建议您检查端口的防火墙或连接问题。