Java RMI圖形界面應(yīng)用程序

在上一章中，我們創(chuàng)建了一個RMI應(yīng)用程序的示例。 在本章中，我們將介紹如何創(chuàng)建一個客戶端調(diào)用顯示GUI窗口(基于JavaFX)的RMI應(yīng)用程序。

定義遠程接口

在這里，首先定義一個名稱為Hello的遠程接口，此接口中有一個名稱為animation()的方法。

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

// Creating Remote interface for our application 
public interface Hello extends Remote { 
   void animation() throws RemoteException; 
}

開發(fā)實現(xiàn)類

在本應(yīng)用程序的Implementation類(遠程對象)中，將創(chuàng)建一個使用JavaFX顯示GUI內(nèi)容的窗口。創(chuàng)建一個Java源代碼文件：FxSample.java，其代碼如下所示 -

import javafx.animation.RotateTransition;  
import javafx.application.Application;  
import javafx.event.EventHandler;   

import javafx.scene.Group;  
import javafx.scene.PerspectiveCamera;  
import javafx.scene.Scene;  
import javafx.scene.control.TextField;  
import javafx.scene.input.KeyEvent;  
import javafx.scene.paint.Color;  
import javafx.scene.paint.PhongMaterial; 

import javafx.scene.shape.Box;  
import javafx.scene.text.Font;  
import javafx.scene.text.FontWeight;
import javafx.scene.text.Text;   
import javafx.scene.transform.Rotate;  

import javafx.stage.Stage;  
import javafx.util.Duration;  

// Implementing the remote interface 
public class FxSample extends Application implements Hello {  
   @Override  
   public void start(Stage stage) { 
      // Drawing a Box  
      Box box = new Box();  

      // Setting the properties of the Box  
      box.setWidth(150.0);  
      box.setHeight(150.0);    
      box.setDepth(100.0);  

      // Setting the position of the box  
      box.setTranslateX(350);   
      box.setTranslateY(150);  
      box.setTranslateZ(50);  

      // Setting the text  
      Text text = new Text(
         "Type any letter to rotate the box, and click on the box to stop the rotation");

      // Setting the font of the text  
      text.setFont(Font.font(null, FontWeight.BOLD, 15));      

      // Setting the color of the text  
      text.setFill(Color.CRIMSON);  

      // Setting the position of the text  
      text.setX(20);  
      text.setY(50); 

      // Setting the material of the box  
      PhongMaterial material = new PhongMaterial();   
      material.setDiffuseColor(Color.DARKSLATEBLUE);   

      // Setting the diffuse color material to box  
      box.setMaterial(material);        

      // Setting the rotation animation to the box     
      RotateTransition rotateTransition = new RotateTransition();  

      // Setting the duration for the transition  
      rotateTransition.setDuration(Duration.millis(1000));  

      // Setting the node for the transition  
      rotateTransition.setNode(box);        

      // Setting the axis of the rotation  
      rotateTransition.setAxis(Rotate.Y_AXIS);  

      // Setting the angle of the rotation 
      rotateTransition.setByAngle(360);  

      // Setting the cycle count for the transition  
      rotateTransition.setCycleCount(50);  

      // Setting auto reverse value to false  
      rotateTransition.setAutoReverse(false);   

      // Creating a text filed  
      TextField textField = new TextField();    

      // Setting the position of the text field  
      textField.setLayoutX(50);  
      textField.setLayoutY(100);  

      // Handling the key typed event  
      EventHandler<KeyEvent> eventHandlerTextField = new EventHandler<KeyEvent>() {  
         @Override  
         public void handle(KeyEvent event) {  
            // Playing the animation  
            rotateTransition.play();  
         }            
      };               

      // Adding an event handler to the text feld  
      textField.addEventHandler(KeyEvent.KEY_TYPED, eventHandlerTextField);  

      // Handling the mouse clicked event(on box)  
      EventHandler<javafx.scene.input.MouseEvent> eventHandlerBox =  
         new EventHandler<javafx.scene.input.MouseEvent>() {  
         @Override  
         public void handle(javafx.scene.input.MouseEvent e) {  
            rotateTransition.stop();   
         }  
      };  

      // Adding the event handler to the box   
      box.addEventHandler(javafx.scene.input.MouseEvent.MOUSE_CLICKED, eventHandlerBox); 

      // Creating a Group object 
      Group root = new Group(box, textField, text);  

      // Creating a scene object  
      Scene scene = new Scene(root, 600, 300);       

      // Setting camera  
      PerspectiveCamera camera = new PerspectiveCamera(false);  
      camera.setTranslateX(0);  
      camera.setTranslateY(0);  
      camera.setTranslateZ(0);  
      scene.setCamera(camera);   

      // Setting title to the Stage
      stage.setTitle("Event Handlers Example");  

      // Adding scene to the stage  
      stage.setScene(scene);  

      // Displaying the contents of the stage  
      stage.show();  
   }  

   // Implementing the interface method 
   public void animation() {  
      launch();  
   }  
}

服務(wù)器程序

RMI服務(wù)器程序應(yīng)實現(xiàn)遠程接口或擴展實現(xiàn)類。 在這里，應(yīng)該創(chuàng)建一個遠程對象并將其綁定到RMIregistry。

以下是本應(yīng)用程序的服務(wù)器程序。在這里，我們將擴展上述創(chuàng)建的類，創(chuàng)建一個遠程對象，并使用綁定名稱：hello 將其注冊到RMI注冊表。創(chuàng)建一個Java源代碼文件：Server.java，其代碼如下所示 -

import java.rmi.registry.Registry; 
import java.rmi.registry.LocateRegistry; 
import java.rmi.RemoteException; 
import java.rmi.server.UnicastRemoteObject; 

public class Server extends FxSample { 
   public Server() {} 
   public static void main(String args[]) { 
      try { 
         // Instantiating the implementation class 
         FxSample obj = new FxSample();

         // Exporting the object of implementation class  
         // (here we are exporting the remote object to the stub) 
         Hello stub = (Hello) UnicastRemoteObject.exportObject(obj, 0);  

         // Binding the remote object (stub) in the registry 
         Registry registry = LocateRegistry.getRegistry(); 

         registry.bind("Hello", stub);  
         System.err.println("Server ready"); 
      } catch (Exception e) { 
         System.err.println("Server exception: " + e.toString()); 
         e.printStackTrace(); 
      } 
   } 
}

客戶端程序

以下是本應(yīng)用程序的客戶端程序。 在這里，我們提取遠程對象并調(diào)用其animation()方法。創(chuàng)建一個Java源代碼文件：Client.java，其代碼如下所示 -

import java.rmi.registry.LocateRegistry; 
import java.rmi.registry.Registry;  

public class Client { 
   private Client() {} 
   public static void main(String[] args) {  
      try { 
         // Getting the registry 
         Registry registry = LocateRegistry.getRegistry(null); 

         // Looking up the registry for the remote object 
         Hello stub = (Hello) registry.lookup("Hello"); 

         // Calling the remote method using the obtained object 
         stub.animation(); 

         System.out.println("Remote method invoked"); 
      } catch (Exception e) {
         System.err.println("Client exception: " + e.toString()); 
         e.printStackTrace(); 
      } 
   } 
}

運行示例的步驟

以下是運行RMI示例的步驟。

第一步 - 打開存儲所有程序的文件夾，并編譯所有Java文件，如下所示。

F:\worksp\java_rmi\java-gui>javac *.java
F:\worksp\java_rmi\java-gui>

第二步 - 使用以下命令啟動rmi注冊表。

start rmiregistry

這將在單獨的窗口中啟動一個rmi注冊表，如下所示。

第三步 - 運行服務(wù)器類文件，如下所示。

F:\worksp\java_rmi\java-gui>java Server
Server ready

第四步 - 運行客戶端類文件，如下所示。

F:\worksp\java_rmi\java-gui> java Client

驗證調(diào)用結(jié)果 - 當啟動客戶端以后，將在服務(wù)器中看到啟動一個圖形界面，如下所示 -