我什么时候应该在 RMI 中实现 java.io.Serializable? [英] When should i implement java.io.Serializable in RMI?

问题描述

我刚刚开始使用 Java RMI，在使用 java.io.Serializable 时遇到了一些问题，所以谁能给我一个必须实现 java.io.Serializable 的 RMI 示例.

谢谢！！！<小时>更新:我做了一个简单的例子，但是，我认为仍然存在问题，因为输出不正确.人机界面

包服务器；导入 java.rmi.Remote;导入 java.rmi.RemoteException;导入 java.rmi.server.UnicastRemoteObject;

公共接口 PersonInterface 扩展 Remote{public void setName(String name) 抛出 RemoteException；public String getPerson() 抛出 RemoteException；public void setAddress(Address address) 抛出 RemoteException；}

个人实施

包服务器；导入 java.rmi.server.UnicastRemoteObject;导入 java.rmi.RemoteException;导入 java.rmi.Naming;导入 java.rmi.Remote;类 Person 扩展 UnicastRemoteObject 实现 PersonInterface{私人字符串名称；私人整数年龄；私人地址地址；Person() 抛出 RemoteException {super();}Person(String name,int age, Address address) 抛出 RemoteException {this.name = 名称；this.age = 年龄；this.address = 地址；}public void setName(String name) 抛出 RemoteException {this.name = 名称；}public void setAddress(Address address) 抛出 RemoteException{this.address = 地址；}public String getPerson() 抛出 RemoteException {返回人:"+姓名+年龄:"+年龄+地址:"+地址；}}

地址类

包服务器；导入 java.io.Serializable;公共类地址实现可序列化{私有静态最终长serialVersionUID = 227L；私人字符串地址1；私人字符串地址2；公共地址() {}公共地址(字符串 addre1，字符串 addre2){this.addre1 = addre1;this.addre2 = addre2;}}

服务器

包服务器；导入 java.rmi.Naming;类服务器{public static void main(String[] args){尝试{//创建一个RemoteDatabaseServer的实例人人 = 新人()；//rmi://[host][:port]/objectString namePerson = "rmi://localhost:9999/person";//将此实例绑定到localhost port999，名称为databaseNaming.bind(namePerson, person);System.out.println("服务器正在运行...");}catch(异常前){System.out.println("服务器异常...");ex.printStackTrace();}}}

客户

打包客户端；导入 java.rmi.RMISecurityManager;导入 java.rmi.Naming;导入 server.PersonInterface;导入服务器.地址；类客户{public static void main(String[] args){尝试{System.setSecurityManager(new RMISecurityManager());String namePerson = "rmi://localhost:9999/person";PersonInterface 人 =(PersonInterface)Naming.lookup(namePerson);person.setName("myName");System.out.println(person.getPerson());person.setName("myNewName");地址 address = new Address("123","123");person.setAddress(地址);System.out.println(person.getPerson());}catch(异常前){System.out.println("客户端失败...");ex.printStackTrace();}}}

我得到的输出是

<前>D:\java -Djava.security.policy=d:\Client\policy\client.policy client.Client人:myName 年龄:0 地址:server.Address@1d6776d人员:myNewName 年龄:0 地址:server.Address@10a2d64

地址打印不正确PS:正如您从 Client 类导入中看到的

import server.PersonInterface;导入服务器.地址；

我已将 PersonInterface.class 和 Address.class 复制到客户端以进行客户端编译.

<小时>最终的:这么笨！！！将以下代码添加到 Address.java

public String toString(){返回地址1+"+地址2；}

好的，问题解决了！！:)

解决方案

interface MyInterface extends Remote {MyClass f(MyClass x) 抛出 RemoteException；}class MyClass 实现了可序列化的 {私有整数值；公共 MyClass(int 值) {this.value = 值；}公共 int getValue() {返回值；}}

你需要Serializable接口来告诉你的类可以通过网络发送

服务器代码

class Service extends UnicastRemoteObject 实现 MyInterface {公共服务() {}公共 MyClass f(MyClass v) 抛出 RemoteException {返回新的 MyClass(v.getValue() + 1)}公共静态无效主(Strint arg []){注册表 r = LocateRegistry.createRegistry(1099);r.rebind("service", new Service());}}

客户端代码

class 客户端 {公共静态无效主(Strint arg []){Registry r = LocateRegistry.getRegistry("localhost", 1099);MyInterface service = (MyInterface)r.lookup("service");MyClass 结果 = service.f(new MyClass(123));System.out.println(result.getValue());//这里打印124}}

I am just starting Java RMI and have some problems with when to use java.io.Serializable, so can anyone give me a RMI example that java.io.Serializable has to be implemented.

Thanks!!!

---

UPDATE: i had made a simple example, however, i think there are still problems as the output is not correct. Person Interface

package server; import java.rmi.Remote; import java.rmi.RemoteException; import java.rmi.server.UnicastRemoteObject;

public interface PersonInterface extends Remote  
{
    public void setName(String name) throws RemoteException;
    public String getPerson() throws RemoteException;
    public void setAddress(Address address) throws RemoteException;
}

Person Implementation

package server;
import java.rmi.server.UnicastRemoteObject;
import java.rmi.RemoteException;
import java.rmi.Naming;
import java.rmi.Remote;

class Person extends UnicastRemoteObject implements PersonInterface
{
    private String name;
    private int age;
    private Address address;


    Person() throws RemoteException {super();}
    Person(String name,int age, Address address) throws RemoteException {
        this.name = name;
        this.age = age;
        this.address = address;
    }

    public void setName(String name) throws RemoteException {
        this.name = name;
    }
    public void setAddress(Address address) throws RemoteException{
        this.address = address;
    }

    public String getPerson() throws RemoteException {
        return "Person : " + name + " age : " + age + " address : " + address;
    }
}

Address Class

package server;
import java.io.Serializable;

public class Address implements Serializable
{
    private static final long serialVersionUID = 227L;
    private String addre1;
    private String addre2;

    public Address() {}
    public Address(String addre1,String addre2){
        this.addre1 = addre1;
        this.addre2 = addre2;   
    }
}

Server

package server;
import java.rmi.Naming;

class Server 
{
    public static void main(String[] args) 
    {
        try{
        //create an instance of the RemoteDatabaseServer
            Person person = new Person();
            //rmi://[host][:port]/object
            String namePerson = "rmi://localhost:9999/person";

            //bind this instance to localhost port999 with name database
            Naming.bind(namePerson, person);
            System.out.println("Server is running...");
        }catch(Exception ex){
            System.out.println("Server Exception...");
            ex.printStackTrace();
        }
    }
}

Client

package client;
import java.rmi.RMISecurityManager;
import java.rmi.Naming;
import server.PersonInterface;
import server.Address;


class Client
{
    public static void main(String[] args) 
    {
        try{
            System.setSecurityManager(new RMISecurityManager());
            String namePerson = "rmi://localhost:9999/person";
            PersonInterface person = 
                (PersonInterface)Naming.lookup(namePerson);

            person.setName("myName");
            System.out.println(person.getPerson());
            person.setName("myNewName");
            Address address = new Address("123","123");
            person.setAddress(address);
            System.out.println(person.getPerson());
        }catch(Exception ex){
            System.out.println("Client failure...");
            ex.printStackTrace();
        }
    }
}

The output i got is

D:\java -Djava.security.policy=d:\Client\policy\client.policy client.Client
Person : myName age : 0 address : server.Address@1d6776d
Person : myNewName age : 0 address : server.Address@10a2d64

The address is not printed correctly PS: As you can see from Client class import

import server.PersonInterface;
import server.Address;

I had copy PersonInterface.class and Address.class to client side to make Client compiled.

---

Final: So stupid!!! Add following code to Address.java

public String toString(){
    return addre1+ " " + addre2;
}

OK, problems are solved!! :)

解决方案

interface MyInterface extends Remote {
  MyClass f(MyClass x) throws RemoteException;
}

class MyClass implements Serializable {
   private int value;
   public MyClass(int value) {
       this.value = value;
   }

   public int getValue() {
       return value;
   }
}

you need Serializable interface to tell that your class can be sent via network

server code

class Service extends UnicastRemoteObject  implements MyInterface {
   public Service() {
   }
   public MyClass f(MyClass v) throws RemoteException {
       return new MyClass(v.getValue() + 1)
   }

   public static void main(Strint arg[]) {
      Registry r = LocateRegistry.createRegistry(1099);
      r.rebind("service", new Service());
   }
}

client code

class Client {
       public static void main(Strint arg[]) {
          Registry r = LocateRegistry.getRegistry("localhost", 1099);
          MyInterface service = (MyInterface)r.lookup("service");

          MyClass result = service.f(new MyClass(123));
          System.out.println(result.getValue());  //print 124 here
       }
  }

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