RMI注意事项

RMI服务接口

提供服务的RMI服务接口必须实现Remote接口

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

import com.google.protobuf.GeneratedMessageLite;
import com.yaowan.h5qipai.protobuf.message.code.Poker.RMIParam;


/**
 * RMI服务
 * @author 
 *
 * @param <T>
 */
public interface RMIService extends Remote{

    public Entity<? extends GeneratedMessageLite> dispatch(Entity<RMIParam> paramEntity )throws RemoteException;
}

RMI服务启动

RMI服务端口

RMI需要两个端口：

• 服务开启端口

Registry registry = LocateRegistry.createRegistry(port);

port端口，用来开启RMI服务，RMI终端连接需要制定连接此端口

String URL = "rmi://"+host+":"+port+"/rmiservice";
rmiService = (RMIService)Naming.lookup(URL);

• 服务交互端口
  RMI终端在与RMI服务端建立连接后会需要利用此端口来进行交互， 而此端口在RMI服务器启动后是随机生成的，这样在防火墙穿透时就不好处理， 因为随机防火墙都不知道对外开放哪个端口了，故在生产环境下是需要制定此端口的，这样我们就需要实现RMISocketFactory类，来指定此端口

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;
import java.rmi.server.RMISocketFactory;

import com.yaowan.framework.util.LogUtil;

public class RMILocalSocketFactory extends RMISocketFactory {

    private int dataPort;
    
    public RMILocalSocketFactory(int dataPort){
        this.dataPort = dataPort;
    }
    @Override
    public ServerSocket createServerSocket(int port) throws IOException {
        if(port == 0){
            port = dataPort;
            LogUtil.info("RMIDataPort: "+port);
        }
        LogUtil.info("RMI createServerSocket: "+port);
        
        return new ServerSocket(port); 
    }

    @Override
    public Socket createSocket(String host, int port) throws IOException {
        String key = host+":"+port;
        LogUtil.info("RMI createSocket: "+key);
        return new Socket(host, port);
    }
}

RMI服务启动

import java.net.MalformedURLException;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.RMISocketFactory;
import java.rmi.server.UnicastRemoteObject;

import org.apache.commons.lang3.exception.ExceptionUtils;

import com.yaowan.framework.core.GlobalConfig;
import com.yaowan.framework.util.LogUtil;

/**
 * RMI服务端启动器
 * @author 
 *
 */
public class RMIServiceServer {
    
    String host;
    private int port;
    private String URL;
    //RMI服务抽象也必须静态化
    private static RMIService rmiService;
    //RMI服务的实现类必须静态化
    private static RMIService rmiServiceImpl;
    public RMIServiceServer(int port) {
        this.port = port;
        this.host = GlobalConfig.getString("IntranetIP");
        URL = "rmi://"+host+":"+port+"/dispatche";
    }
    /**
     * 用于启动RMI服务
     */
    public void start() {
        try {
//          System.setProperty("java.rmi.server.hostname", host);
            
            int dataPort = GlobalConfig.getInt("RMIDataPort");
            if(dataPort == 0){//如果未设置，默认用此端口
                dataPort = 19998;
            }
            
            RMISocketFactory.setSocketFactory(new RMILocalSocketFactory(dataPort));
            //RMI服务的实现类必须静态化
            rmiServiceImpl = new RMIServiceImpl();
            //RMI服务抽象也必须静态化
            rmiService=(RMIService)UnicastRemoteObject.exportObject(rmiServiceImpl,0); //固定端口设置,配合在RMISocketFactory实现中做处理
            
            System.setProperty("java.rmi.server.hostname",host);
            
            LogUtil.info("Binding server implementation to registry");
            Registry registry = LocateRegistry.createRegistry(port);
            
            registry.rebind("dispatche", rmiService);
//          Naming.rebind(URL, rmiService);
            LogUtil.info("Waiting for invocations from clients ...");
            LogUtil.info("URL: "+URL);
            
        } catch (RemoteException e) {
            LogUtil.error(ExceptionUtils.getStackFrames(e));
        } catch (MalformedURLException e) {
            LogUtil.error(ExceptionUtils.getStackFrames(e));
        }catch(Exception e){
            LogUtil.error(ExceptionUtils.getStackFrames(e));
        }
    }
}

需要注意点:

• RMI服务抽象也必须静态化
• RMI服务的实现类必须静态化