javascript - 处理 - 如何将数据（通过 websockets？）发送到 javascript 应用程序

Question

我正在玩处理，想知道我是否可以将数据从处理发送到 javascript 应用程序。是否有可能创建具有处理功能的（例如 websocket）服务器？

提前致谢！

Answer 1

我已经在 Eclipse 中尝试了Java WebSockets for desktop（有或没有扩展 PApplet），它也适用于 Android。如果你想在处理中使用库，你需要这样做：

1. 在 Documents/Processing/libraries 中创建一个名为java_websocket的文件夹
2. 在新创建的 java_websocket 文件夹中创建另一个名为library的文件夹并将java_websocket.jar 放在那里
3. 重新启动处理并开始使用库（sketch > import library 现在应该列出 java_websocket）

这是正在处理的项目示例代码： 服务器：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.InetSocketAddress;
import java.net.UnknownHostException;
import java.util.Collection;

import org.java_websocket.WebSocket;
import org.java_websocket.WebSocketImpl;
import org.java_websocket.handshake.ClientHandshake;
import org.java_websocket.server.WebSocketServer;

void setup(){
  new ServerThread().start();
}
//create a separate thread for the server not to freeze/interfere with Processing's default animation thread
public class ServerThread extends Thread{
  @Override
  public void run(){
    try{
          WebSocketImpl.DEBUG = true;
          int port = 8887; // 843 flash policy port
          try {
            port = Integer.parseInt( args[ 0 ] );
          } catch ( Exception ex ) {
          }
          ChatServer s = new ChatServer( port );
          s.start();
          System.out.println( "ChatServer started on port: " + s.getPort() );

          BufferedReader sysin = new BufferedReader( new InputStreamReader( System.in ) );
          while ( true ) {
            String in = sysin.readLine();
            s.sendToAll( in );
          }
        }catch(IOException e){
          e.printStackTrace();
        }  
  }
}
public class ChatServer extends WebSocketServer {

  public ChatServer( int port ) throws UnknownHostException {
    super( new InetSocketAddress( port ) );
  }

  public ChatServer( InetSocketAddress address ) {
    super( address );
  }

  @Override
  public void onOpen( WebSocket conn, ClientHandshake handshake ) {
    this.sendToAll( "new connection: " + handshake.getResourceDescriptor() );
    System.out.println( conn.getRemoteSocketAddress().getAddress().getHostAddress() + " entered the room!" );
  }

  @Override
  public void onClose( WebSocket conn, int code, String reason, boolean remote ) {
    this.sendToAll( conn + " has left the room!" );
    System.out.println( conn + " has left the room!" );
  }

  @Override
  public void onMessage( WebSocket conn, String message ) {
    this.sendToAll( message );
    System.out.println( conn + ": " + message );
  }

  @Override
  public void onError( WebSocket conn, Exception ex ) {
    ex.printStackTrace();
    if( conn != null ) {
      // some errors like port binding failed may not be assignable to a specific websocket
    }
  }

  /**
   * Sends <var>text</var> to all currently connected WebSocket clients.
   * 
   * @param text
   *            The String to send across the network.
   * @throws InterruptedException
   *             When socket related I/O errors occur.
   */
  public void sendToAll( String text ) {
    Collection<WebSocket> con = connections();
    synchronized ( con ) {
      for( WebSocket c : con ) {
        c.send( text );
      }
    }
  }
}

一个测试客户：

import java.awt.Container;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowEvent;
import java.net.URI;
import java.net.URISyntaxException;

import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;

import org.java_websocket.WebSocketImpl;
import org.java_websocket.client.WebSocketClient;
import org.java_websocket.drafts.Draft;
import org.java_websocket.drafts.Draft_10;
import org.java_websocket.drafts.Draft_17;
import org.java_websocket.drafts.Draft_75;
import org.java_websocket.drafts.Draft_76;
import org.java_websocket.handshake.ServerHandshake;

void setup(){
  WebSocketImpl.DEBUG = true;
  new ChatClient( "ws://localhost:8887" );
}

public class ChatClient extends JFrame implements ActionListener {
  private static final long serialVersionUID = -6056260699202978657L;

  private final JTextField uriField;
  private final JButton connect;
  private final JButton close;
  private final JTextArea ta;
  private final JTextField chatField;
  private final JComboBox draft;
  private WebSocketClient cc;

  public ChatClient( String defaultlocation ) {
    super( "WebSocket Chat Client" );
    Container c = getContentPane();
    GridLayout layout = new GridLayout();
    layout.setColumns( 1 );
    layout.setRows( 6 );
    c.setLayout( layout );

    Draft[] drafts = { new Draft_17(), new Draft_10(), new Draft_76(), new Draft_75() };

    draft = new JComboBox( drafts );
    c.add( draft );

    uriField = new JTextField();
    uriField.setText( defaultlocation );
    c.add( uriField );

    connect = new JButton( "Connect" );
    connect.addActionListener( this );
    c.add( connect );

    close = new JButton( "Close" );
    close.addActionListener( this );
    close.setEnabled( false );
    c.add( close );

    JScrollPane scroll = new JScrollPane();
    ta = new JTextArea();
    scroll.setViewportView( ta );
    c.add( scroll );

    chatField = new JTextField();
    chatField.setText( "" );
    chatField.addActionListener( this );
    c.add( chatField );

    java.awt.Dimension d = new java.awt.Dimension( 300, 400 );
    setPreferredSize( d );
    setSize( d );

    addWindowListener( new java.awt.event.WindowAdapter() {
      @Override
      public void windowClosing( WindowEvent e ) {
        if( cc != null ) {
          cc.close();
        }
        dispose();
      }
    } );

    setLocationRelativeTo( null );
    setVisible( true );
  }

  public void actionPerformed( ActionEvent e ) {

    if( e.getSource() == chatField ) {
      if( cc != null ) {
        cc.send( chatField.getText() );
        chatField.setText( "" );
        chatField.requestFocus();
      }

    } else if( e.getSource() == connect ) {
      try {
        // cc = new ChatClient(new URI(uriField.getText()), area, ( Draft ) draft.getSelectedItem() );
        cc = new WebSocketClient( new URI( uriField.getText() ), (Draft) draft.getSelectedItem() ) {

          @Override
          public void onMessage( String message ) {
            ta.append( "got: " + message + "\n" );
            ta.setCaretPosition( ta.getDocument().getLength() );
          }

          @Override
          public void onOpen( ServerHandshake handshake ) {
            ta.append( "You are connected to ChatServer: " + getURI() + "\n" );
            ta.setCaretPosition( ta.getDocument().getLength() );
          }

          @Override
          public void onClose( int code, String reason, boolean remote ) {
            ta.append( "You have been disconnected from: " + getURI() + "; Code: " + code + " " + reason + "\n" );
            ta.setCaretPosition( ta.getDocument().getLength() );
            connect.setEnabled( true );
            uriField.setEditable( true );
            draft.setEditable( true );
            close.setEnabled( false );
          }

          @Override
          public void onError( Exception ex ) {
            ta.append( "Exception occured ...\n" + ex + "\n" );
            ta.setCaretPosition( ta.getDocument().getLength() );
            ex.printStackTrace();
            connect.setEnabled( true );
            uriField.setEditable( true );
            draft.setEditable( true );
            close.setEnabled( false );
          }
        };

        close.setEnabled( true );
        connect.setEnabled( false );
        uriField.setEditable( false );
        draft.setEditable( false );
        cc.connect();
      } catch ( URISyntaxException ex ) {
        ta.append( uriField.getText() + " is not a valid WebSocket URI\n" );
      }
    } else if( e.getSource() == close ) {
      cc.close();
    }
  }


}

这几乎是冗长的粘贴 Java 代码。但是如果需要，制作一些帮助器/包装器类应该很容易。

快速搜索会返回这些方便的结果：

• 处理论坛线程
• PWS
• 带有 websockets 和处理的简单网络摄像头
• 通过 WebSocket 处理

更新

我最近被介绍到一个名为spacebrew的新 Websockets 库，它非常适合您的查询，特别是因为它们似乎在幕后很好地包装了 java_websocket。

现在您将其用作任何其他处理库，使用大大简化（不需要 java 库经验，只需处理即可）并且示例很棒！

我通过另一个问题了解了这一点，这让我发现它实际上可以在你的 Android 设备上开箱即用（只需要检查 INTERNET 框）。那有多棒？

让所有那些甜蜜的 websocket 动作像它一样进行并不是没有任何好处，它是 android 支持的。

在您的桌面上快速制作原型，然后让您的项目从您的口袋中工作。

太空酿造♥处理