Java学习笔记----------------RMI操作

这个例子不是RMI入门级的，但是也不难

首先是两个实体类，用来保存客户信息及留言信息

User.java

/**
 * 保存用户的实体类
 * 
 * @author 白强
 * 
 */
public class User {
    private String userName;
    private String password;
    public Message msg[] = new Message[100];
    // the total number of users
    public int num = 0;

    public User(String name, String psw) {
        userName = name;
        password = psw;
        num = 0;
    }

    public void setUserName(String name) {

        userName = name;
    }

    public String getUserName() {

        return userName;
    }

    public void setPassword(String psw) {

        password = psw;
    }

    public String getPassword() {

        return password;
    }
}

Message.java

import java.util.Date;

/**
 * 保存消息的实体
 * 
 * @author 白强
 * 
 */
public class Message {

    private String sender;
    private String receiver;
    private String msgText;
    private Date date;

    public Message(String sender, String receiver, String msgText, Date date) {
        super();
        this.sender = sender;
        this.receiver = receiver;
        this.msgText = msgText;
        this.date = date;
    }

    public String getSender() {
        return sender;
    }

    public void setSender(String sender) {
        this.sender = sender;
    }

    public String getReceiver() {
        return receiver;
    }

    public void setReceiver(String receiver) {
        this.receiver = receiver;
    }

    public String getMsgText() {
        return msgText;
    }

    public void setMsgText(String msgText) {
        this.msgText = msgText;
    }

    public Date getDate() {
        return date;
    }

    public void setDate(Date date) {
        this.date = date;
    }

}

---

RMI的接口

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

/**
 * RMI接口
 * 
 * @author 白强
 * 
 */
public interface MessageCenter extends Remote {

    /**
     * @param userName
     * @param password
     * @return 注册结果
     * @throws RemoteException
     */
    String register(String userName, String password) throws RemoteException;

    /**
     * @return 用户列表
     * @throws RemoteException
     */
    String showUsers() throws RemoteException;

    /**
     * @param uName
     * @param psw
     * @return 留言列表
     * @throws RemoteException
     */
    String checkMessage(String uName, String psw) throws RemoteException;

    /**
     * @param sender
     * @param receiver
     * @param message
     * @return 留言信息
     * @throws RemoteException
     */
    String leaveMessage(String sender, String receiver, String message)
            throws RemoteException;
}

接口的实现

import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;
import java.util.ArrayList;
import java.util.Date;

/**
 * RMI实现类
 * 
 * @author 白强
 * 
 */
public class MessageCenterImpl extends UnicastRemoteObject implements
        MessageCenter {

    private static final long serialVersionUID = 1L;
    ArrayList<User> list = new ArrayList<User>();
    String show = "";

    public MessageCenterImpl() throws RemoteException {
    }

    /*
     * (non-Javadoc)
     * 
     * @see MessageCenter#register(java.lang.String, java.lang.String)
     */
    @Override
    public String register(String userName, String password)
            throws RemoteException {
        for (int i = 0; i < list.size(); i++) {
            if (list.get(i).getUserName().equals(userName)) {
                show = "The user existes!!!!!!";
                return show;
            }
        }
        User newUser = new User(userName, password);
        list.add(newUser);
        show = "Register Successful";
        // System.out.println(userName + " has  registered");
        return show;
    }

    /*
     * (non-Javadoc)
     * 
     * @see MessageCenter#showUsers()
     */
    @Override
    public String showUsers() throws RemoteException {
        if (list.size() == 0) {
            show = " There are no users utill now.";
        } else {
            show = "users :" + "
";
            for (int i = 0; i < list.size(); i++) {
                show += (i + 1) + " : " + list.get(i).getUserName() + "
";
            }
        }
        return show;
    }

    /*
     * (non-Javadoc)
     * 
     * @see MessageCenter#checkMessage(java.lang.String, java.lang.String)
     */
    @Override
    public String checkMessage(String uName, String psw) throws RemoteException {
        if (list.size() != 0) {

            for (int i = 0; i < list.size(); i++) {
                // only the registered users can check their messages.
                if (list.get(i).getUserName().equals(uName)
                        && list.get(i).getPassword().equals(psw)) {
                    int j = list.get(i).num;
                    if (j == 0) {
                        show = "No message for you";
                    } else {// show all the message for the user.
                        show = "There are Messages :" + "
";
                        for (int k = 0; k < j; k++) {
                            show += " From : " + list.get(i).msg[k].getSender()
                                    + " Message :"
                                    + list.get(i).msg[k].getMsgText()
                                    + " Time: " + list.get(i).msg[k].getDate()
                                    + "
";
                        }
                    }
                }
            }
            if (show.equals("")) {
                show = "Wrong userName or password";
            }
        } else {
            // No users
            show = "There are no users.";
        }
        return show;
    }

    /*
     * (non-Javadoc)
     * 
     * @see MessageCenter#leaveMessage(java.lang.String, java.lang.String,
     * java.lang.String)
     */
    @Override
    public String leaveMessage(String sender, String receiver, String message)
            throws RemoteException {
        show = "";

        for (int i = 0; i < list.size(); i++) {

            if (list.get(i).getUserName().equals(sender)) {

                for (int j = 0; j < list.size(); j++) {

                    if (list.get(j).getUserName().equals(receiver)) {
                        Date d = new Date();
                        // the date and time the message was left.
                        Message ml = new Message(sender, receiver, message, d);
                        // create a new message.
                        list.get(j).msg[list.get(j).num] = ml;
                        list.get(j).num++;
                        // add one to the user's total message number.
                        show = "Leave Message Successfully!!";
                    }
                }
                if (show == "") {
                    // if the receiver do not exist.
                    show = "the receiver do not exist.";
                }
            }
        }
        if (show == "") {
            // if the sender have not registered.
            show = "Please register first!";
        }

        return show;
    }
}

---

RMIServer 用来发布远程服务

import java.rmi.Naming;
import java.rmi.registry.LocateRegistry;

/**
 * RMIServer
 * 
 * @author 白强
 * 
 */
public class MessageServer {

    public static void main(String[] args) {
        try {
            MessageCenter messageService = new MessageCenterImpl();
            String host = "localhost";
            int port = 8888;
            if (args.length > 1) {
                host = args[0];
                port = Integer.parseInt(args[1]);
            }
            // 注册，切记不能少
            LocateRegistry.createRegistry(port);
            String registration = "rmi://" + host + ":" + port
                    + "/MessageCenter";
            Naming.bind(registration, messageService);
            System.out.println("Start RMI service Successfully!!! ");
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}

---

客户端，用来远程连接操作

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.rmi.Naming;
import java.rmi.Remote;

/**
 * RMI的客户端类
 * 
 * @author 白强
 * 
 */
public class MessageClient {

    public MessageClient(String registration) throws Exception {
        Remote remoteService = Naming.lookup(registration);
        MessageCenter messageService = (MessageCenter) remoteService;
        while (true) {
            displayMenu();
            BufferedReader br = new BufferedReader(new InputStreamReader(
                    System.in));
            try {
                int actionID = Integer.parseInt(br.readLine());
                switch (actionID) {
                case 1:
                    // Register
                    System.out.println("Enter your name: ");
                    BufferedReader bfReader1 = new BufferedReader(
                            new InputStreamReader(System.in));
                    String userName = bfReader1.readLine();
                    System.out.println("Enter your password: ");
                    BufferedReader bfReader2 = new BufferedReader(
                            new InputStreamReader(System.in));
                    String psw = bfReader2.readLine();
                    System.out.println(messageService.register(userName, psw));
                    break;
                case 2:
                    // showUser
                    System.out.println(messageService.showUsers());
                    break;
                case 3:
                    // checkMessage
                    System.out.println("Enter your name: ");
                    BufferedReader bfReader3 = new BufferedReader(
                            new InputStreamReader(System.in));
                    String checkUserName = bfReader3.readLine();
                    // get the user's password.
                    System.out.println("Enter your password: ");
                    BufferedReader bfReader4 = new BufferedReader(
                            new InputStreamReader(System.in));
                    String checkpsw = bfReader4.readLine();
                    System.out.println(messageService.checkMessage(
                            checkUserName, checkpsw));
                    break;
                case 4:
                    // leaveMessage
                    System.out.println("Enter your name: ");
                    BufferedReader bfReader5 = new BufferedReader(
                            new InputStreamReader(System.in));
                    String leaveUserName = bfReader5.readLine();
                    // get the receiver's name.
                    System.out
                            .println("Enter the name which the message send to: ");
                    BufferedReader bfReader6 = new BufferedReader(
                            new InputStreamReader(System.in));
                    String receiver = bfReader6.readLine();
                    // get the message context.
                    System.out.println("Enter the message: ");
                    BufferedReader bfReader7 = new BufferedReader(
                            new InputStreamReader(System.in));
                    String msg = bfReader7.readLine();
                    System.out.println(messageService.leaveMessage(
                            leaveUserName, receiver, msg));
                    break;
                case 5:
                    System.exit(0);
                    break;
                default:
                    System.out.println("Invalid input!");
                }
            } catch (NumberFormatException nfe) {
                System.out.println("Invalid input!");
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 用来显示选项
     */
    public void displayMenu() {
        System.out.println("");
        System.out.println("Input a number :");
        System.out.println("");
        System.out.println("----Designed by BaiQiang------Start--------");
        System.out.println("      1 : Register");
        System.out.println("      2 : ShowsUsers");
        System.out.println("      3 : CheckMessage");
        System.out.println("      4 : LeaveMessage");
        System.out.println("    5 : Exit");
        System.out.println("----Designed by BaiQiang-------End--------");
    }

    public static void main(String[] args) throws Exception {
        String registry = "localhost";
        int port = 8888;
        if (args.length > 1) {
            registry = args[0];
            port = Integer.parseInt(args[1]);
        }
        String registration = "rmi://" + registry + ":" + port
                + "/MessageCenter";
        new MessageClient(registration);
    }
}

---

All Right!!!!!!!!!