我正在尝试使用java RMI在服务器(在Pi上)和客户端(在另一个PI上)之间进行通信。客户端能够调用服务器的远程方法,但是当服务器尝试访问客户端的远程方法时,我收到错误Connection refused to Host 127.0.0.1.
为了解决这个问题,我设置了System.setProperty("java.rmi.server.hostname", ServerIP;
,但随后得到错误Connection refused to Host 10.10.*.*.
主接口看起来像
import java.rmi.Remote;
import java.rmi.RemoteException;
public interface MasterInterface extends Remote{
public void sayHello(String s) throws RemoteException;
}
主.java文件如下所示
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;
public class Master extends UnicastRemoteObject implements MasterInterface{
protected Master() throws RemoteException {
super();
// TODO Auto-generated constructor stub
}
/**
*
*/
private static final long serialVersionUID = 1L;
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
try {
System.setProperty("java.rmi.server.hostname", "192.168.4.*");
Master master = new Master();
Registry reg = LocateRegistry.createRegistry(9898);
reg.rebind("Master", master);
System.out.println("Master is on.123123132.test.");
} catch (RemoteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
@Override
public void sayHello(String s) throws RemoteException {
// TODO Auto-generated method stub
System.out.println("Hiiiiiii ->>>>>"+s);
try{
Registry regi2 = LocateRegistry.getRegistry("192.168.*.*", 9898);
System.out.println("asdasdasd1!!");
SlaveInterface bsObj1 = (SlaveInterface) regi2.lookup("Slave");
bsObj1.saybye("madhav");
}catch(Exception e){
e.printStackTrace();
}
}
}
从属接口看起来像
import java.rmi.Remote;
import java.rmi.RemoteException;
public interface SlaveInterface extends Remote{
public void saybye(String s) throws RemoteException;
}
从属.java文件看起来像
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;
public class Slave extends UnicastRemoteObject implements SlaveInterface {
private final static String master_IP = "192.168.4.*";
protected Slave() throws RemoteException {
super();
// TODO Auto-generated constructor stub
}
/**
*
*/
private static final long serialVersionUID = 1L;
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
try{
System.setProperty("java.rmi.server.hostname", "192.168.*.*");
Slave s = new Slave();
Registry regclient = LocateRegistry.createRegistry(2525);
System.out.println("slave obj bound!!");
regclient.rebind("Slave", s);
System.out.println("Slave is on..");
Registry regi = LocateRegistry.getRegistry(master_IP, 9898);
System.out.println("slave obj bound1111!!");
MasterInterface bsObj = (MasterInterface) regi.lookup("Master");
System.out.println("slave obj bound2222!!");
bsObj.sayHello("hi karan");
System.out.println("done................");
}catch(Exception e){
System.out.println("not working!!!!!!!!!!");
e.printStackTrace();
}
}
@Override
public void saybye(String s) throws RemoteException {
// TODO Auto-generated method stub
System.out.println("bye "+s);
}
}
导出任何远程对象之前,将java.rmi.server.hostname
设置为服务器 JVM 中服务器的外部 IP 地址。请参阅 RMI 常见问题解答第 A.1 项。
遇到过这个问题,因为名称解析(默认情况下主机名将解析为 127.0.0.1 - 环回接口的 IP 地址)。
如果您没有 DNS 服务器,请尝试以下操作:
为两个 Pi 分配不同的主机名(在 /etc/hostname
中设置)或使用 hostname
命令。
"client"作为主机名,并且 10.10.10.13 和 10.10.10.14 是它们的 IP 地址,请将以下信息添加到文件 /etc/hosts
中,在两个 Pi 中:
10.10.10.13 master
10.10.10.14 client