Socket连接技术

技术2022-05-11 61

使用Socket 是连接两台计算机最简单的方法，另外由于Socket 使用的是TCP 协议，所以也就保证了传输的质量。但在这里要注意的是，并不是所有的MIDP 设备都支持Socket 网络。在这部分中我们主要涉及到的两个接口是SocketConnection 和ServerSocketConnection。这个两个接口的使用方法其实和J2SE 中的Socket 和ServerSocket 类的使用方法很相似。不同的是ServerSocketConnection 中打开一个SocketConnection 作为监听者的方法是acceptAndOpen()。同时你可以用getLocalAddress()和getLocalPort()两个方法获得本地的绑定IP 地址和所打开的端口号，这样你就可以告诉另外一台MIDP 设备你所使用的IP 和端口，使得另一台MIDP 设备可以连接到你的设备上。在这里我们除了强调使用acceptAndOpen()从一个ServerSocketConnection 对象中打开一个SocketConnection 作为监听者外，还要说明的是作为套接字我们是可以设置一些属性的，这些属性的设置是通过SocketConnection.setSocketOption()方法来设置

package socketText; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import javax.microedition.io.Connector; import javax.microedition.io.ServerSocketConnection; import javax.microedition.io.SocketConnection; import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.Command; import javax.microedition.lcdui.CommandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.lcdui.StringItem; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.midlet.MIDletStateChangeException; /** * * @author leilu 服务器端代码 */ public class SocketServer extends MIDlet implements CommandListener, Runnable { private Display display; private Form f; private StringItem si; private TextField tf; private boolean stop; // 创建Command对象 private Command sendCommand = new Command("send", Command.ITEM, 1); private Command exitCommand = new Command("Exit", Command.EXIT, 1); // 输入流 InputStream is; // 输出流 OutputStream os; // Socket连接 SocketConnection sc; // Socket服务器连接 ServerSocketConnection scn; public SocketServer() { display = Display.getDisplay(this); f = new Form("Socket Server"); si = new StringItem("Status:", " "); // 显示发送消息的控件 tf = new TextField("Send:", "", 30, TextField.ANY); f.append(si); f.append(tf); f.addCommand(exitCommand); // f.addCommand(sendCommand); f.setCommandListener(this); display.setCurrent(f); // 启动线程 Thread t = new Thread(this); t.start(); } protected void startApp() throws MIDletStateChangeException { // TODO Auto-generated method stub } protected void pauseApp() { // TODO Auto-generated method stub } protected void destroyApp(boolean arg0) throws MIDletStateChangeException { // TODO Auto-generated method stub } public void commandAction(Command c, Displayable d) { if (sendCommand == c) { try { os.write(tf.getString().getBytes()); os.write(" ".getBytes()); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } else if (exitCommand == c) { try { destroyApp(false); this.notifyDestroyed(); } catch (MIDletStateChangeException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } public void run() { si.setText("Waiting for connection"); // 创建一个服务器的ServerSocketConnection连接 try { scn = (ServerSocketConnection) Connector.open("socket://:5000"); // 等待一个连接 sc = (SocketConnection) scn.acceptAndOpen(); // 设置提示信息 si.setText("Connection accepted"); is = sc.openInputStream(); os = sc.openOutputStream(); // 连接完成后允许发送 f.addCommand(sendCommand); // 读取客户端发来的消息 while (true) { StringBuffer sb = new StringBuffer(); int c = 0; // 读取数据 while (((c = is.read()) != ' ') && (c != -1)) { sb.append((char) c); } // 如果读取数据失败 if (c == -1) { break; } // 显示客户端反发送过来的消息 si.setText("Message receved-" + sb.toString()); } si.setText("Connection is closed"); // 连接结束，则不实现发送按钮 f.removeCommand(sendCommand); } catch (IOException ioe) { if (ioe.getMessage().equals("ServerSocket Open")) { // 提示端口己经被占用 Alert a = new Alert("Server", "Port 5000 is already taken.", null, AlertType.ERROR); a.setTimeout(Alert.FOREVER); a.setCommandListener(this); display.setCurrent(a); } else { if (!stop) { ioe.printStackTrace(); } } } catch (Exception e) { e.printStackTrace(); } } // 释放资源 public void stop() { try { stop = true; if (is != null) { is.close(); } if (os != null) { os.close(); } if (sc != null) { sc.close(); } if (scn != null) { scn.close(); } } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } }}

package socketText; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import javax.microedition.io.ConnectionNotFoundException; import javax.microedition.io.Connector; import javax.microedition.io.SocketConnection; import javax.microedition.lcdui.Alert; import javax.microedition.lcdui.AlertType; import javax.microedition.lcdui.Command; import javax.microedition.lcdui.CommandListener; import javax.microedition.lcdui.Display; import javax.microedition.lcdui.Displayable; import javax.microedition.lcdui.Form; import javax.microedition.lcdui.StringItem; import javax.microedition.lcdui.TextField; import javax.microedition.midlet.MIDlet; import javax.microedition.midlet.MIDletStateChangeException; public class SocketClient extends MIDlet implements Runnable, CommandListener { private Display display; private Form f; private StringItem si; private TextField tf; private boolean stop; // 创建Command对象 private Command sendCommand = new Command("send", Command.ITEM, 1); private Command exitCommand = new Command("Exit", Command.EXIT, 1); // 输入流 InputStream is; // 输出流 OutputStream os; // Socket连接 SocketConnection sc; public SocketClient() { display = Display.getDisplay(this); f = new Form("Socket Server"); si = new StringItem("Status:", " "); // 显示发送消息的控件 tf = new TextField("Send:", "", 30, TextField.ANY); f.append(si); f.append(tf); f.addCommand(exitCommand); f.addCommand(sendCommand); f.setCommandListener(this); display.setCurrent(f); // 启动线程 Thread t = new Thread(this); t.start(); } protected void startApp() throws MIDletStateChangeException { // TODO Auto-generated method stub } protected void pauseApp() { // TODO Auto-generated method stub } protected void destroyApp(boolean arg0) throws MIDletStateChangeException { // TODO Auto-generated method stub } public void run() { try { // 打开一个连接本地服务器的SocketConnection sc = (SocketConnection) Connector.open("socket://localhost:5000"); si.setText("Connected to server"); // 设置提示信息 si.setText("Connection accepted"); is = sc.openInputStream(); os = sc.openOutputStream(); // 读取服务器端发来的消息 while (true) { StringBuffer sb = new StringBuffer(); int c = 0; // 读取数据 while (((c = is.read()) != ' ') && (c != -1)) { sb.append((char) c); } // 如果读取数据失败 if (c == -1) { break; } // 显示消息 si.setText("Message receved-" + sb.toString()); } // 停止连接 stop(); si.setText("Connection is closed"); // 连接结束，则不实现发送按钮 f.removeCommand(sendCommand); } catch (ConnectionNotFoundException cnf) { // 提示端口己经被占用 Alert a = new Alert("Client", "please run server first.", null, AlertType.ERROR); a.setTimeout(Alert.FOREVER); a.setCommandListener(this); display.setCurrent(a); } catch(IOException ioe) { if (!stop) { ioe.printStackTrace(); } } catch (Exception e) { e.printStackTrace(); } } public void commandAction(Command c, Displayable d) { if (sendCommand == c) { try { os.write(tf.getString().getBytes()); os.write(" ".getBytes()); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } else if (exitCommand == c) { try { destroyApp(false); this.notifyDestroyed(); } catch (MIDletStateChangeException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } public void stop() { try { stop = true; if (is != null) { is.close(); } if (os != null) { os.close(); } if (sc != null) { sc.close(); } } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } }}

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