题目：做一个简单的收发电子邮件的代码。还需各位指教！
/*客户端代码*/ import javax.mail.*; import javax.mail.internet.*; import java.util.*; import java.io.*; public class MailClient { public static void main(String[] args){ if (args.length == 0){ System.err.println("Usage:javaMailClient protocol://username:password@host:port/foldername"); return; } URLName server = new URLName(args[0]); try { Session session = Session.getDefaultInstance(new Properties(), null); Folder folder = session.getFolder(server); if (folder == null) { System.out.println("Folder " + server.getFile() + " not found."); System.exit(1); } folder.open(Folder.READ_ONLY); Message[] messages = folder.getMessages(); for (int i = 0; i < messages.length; i++) { System.out.println("------------ Message " + (i+1) + " ------------"); messages[i].writeTo(System.out); } folder.close(false); } catch (Exception e) { e.printStackTrace(); } } } /*服务器端代码*/ import java.applet.Applet; import java.awt.*; import java.io.*; import java.net.*; public class WebSendMail extends Applet{ // 初始化界面 public void init(){ String s = getParameter("BgColor"); if(s == null) s = "0,0,0"; bgcolor = param.decodeColor(s); String s1 = getParameter("FgColor"); if(s1 == null) s1 = "255,255,255"; fgcolor = param.decodeColor(s1); in_mailto = getParameter("MailTo"); if(in_mailto == null) in_mailto = ""; in_website = getParameter("Website"); if(in_website == null) in_website = ""; d = size(); SuperCedeInit(); } public void sendMsg() { // 处理消息发送 try { button_Send.disable(); button_Clear.disable(); host = getCodeBase().getHost(); if(host.length() == 0) host = "localhost"; textArea_Log.appendText("Connecting. '" + host + "'\n"); Socket socket = new Socket(host, 25); textArea_Log.appendText("Connect OK '" + host + "'\n"); // 创建输入输出流 DataOutputStream dataoutputstream = new DataOutputStream(socket.getOutputStream()); DataInputStream datainputstream = new DataInputStream(socket.getInputStream()); textArea_Log.appendText("Send Start '" + textField_Subject.getText() + "'\n"); textArea_Log.appendText(datainputstream.readLine() + "\n"); dataoutputstream.writeBytes("HELO " + host + "\n"); textArea_Log.appendText(datainputstream.readLine() + "\n"); dataoutputstream.writeBytes("MAIL FROM: " + textField_From.getText() + "\n"); textArea_Log.appendText(datainputstream.readLine() + "\n"); dataoutputstream.writeBytes("RCPT TO: " + textField_To.getText() + "\n"); textArea_Log.appendText(datainputstream.readLine() + "\n"); dataoutputstream.writeBytes("DATA\n"); textArea_Log.appendText(datainputstream.readLine() + "\n"); dataoutputstream.writeBytes("X-Mailer: WebSendMail\n"); dataoutputstream.writeBytes("X-WebSite: " + in_website + "\n"); dataoutputstream.writeBytes("Subject: " + textField_Subject.getText() + "\n" + textArea_Msg.getText() + "\n"); dataoutputstream.writeBytes(".\nQUIT\n"); textArea_Log.appendText(datainputstream.readLine() + "\n------------------------------\n"); socket.close(); button_Send.enable(); button_Clear.enable(); button_Send.enable(); button_Clear.enable(); return; } catch(UnknownHostException _ex) { // 处理连接异常 textArea_Log.appendText("Connect Error '" + host + "'\n"); return; } catch(IOException _ex) { button_Send.enable(); } button_Clear.enable(); textArea_Log.appendText("Send Error '" + textField_Subject.getText() + "'\n"); } public void paint(Graphics g){} protected void Button_SendClicked(Event event) { // 处理发送按钮点击事件 if(textField_From.getText().length() == 0){ // 如果信件来源为空 textArea_Log.appendText("Input? 'From'\n"); return; } if(textField_To.getText().length() == 0) { // 如果信件目的地为空 textArea_Log.appendText("Input? 'To'\n"); return; } if(textField_Subject.getText().length() == 0){ // 如果信件主题为空 textArea_Log.appendText("Input? 'Subject'\n"); return; } if(textArea_Msg.getText().length() == 0) { // 如果信件内容为空 textArea_Log.appendText("Input? 'Message'\n"); return; } else { sendMsg(); return; } } protected void Button_ClearClicked(Event event) {// 清除按钮点击处理，清空所有已填内容 textField_Subject.setText(""); textField_From.setText(""); textField_To.setText(in_mailto); textArea_Msg.setText(""); } protected void Button_ClearLogClicked(Event event) { // 清空日志 textArea_Log.setText(""); } // 调用或重载超类相关方法实现初始化、开始、结束以及事件处理等 public boolean handleEvent(Event event) { return SuperCedeEvent(event); } public void start() { SuperCedeStart(); } public void stop() { SuperCedeStop(); } public String getAppletInfo() { return "WebSendMail"; } private final void SuperCedeInit() { // 详细的界面设置 setLayout(null); setForeground(fgcolor); setBackground(bgcolor); addNotify(); resize(d.width, d.height); label4 = new Label("From :", 2); label4.setForeground(fgcolor); add(label4); int i = insets().left; label4.reshape(i, insets().top, 50, 22); textField_From = new TextField(""); textField_From.setEditable(true); textField_From.setForeground(new Color(0, 0, 0)); textField_From.setBackground(new Color(255, 255, 255)); add(textField_From); int j = insets().left + 50; textField_From.reshape(j, insets().top, d.width - 50, 22); label3 = new Label("To :", 2); label3.setForeground(fgcolor); add(label3); int k = insets().left; label3.reshape(k, insets().top + 22, 50, 22); textField_To = new TextField(in_mailto); textField_To.setEditable(true); textField_To.setForeground(new Color(0, 0, 0)); textField_To.setBackground(new Color(255, 255, 255)); add(textField_To); int l = insets().left + 50; textField_To.reshape(l, insets().top + 22, d.width - 50, 22); label_Subject = new Label("Subject :", 2); label_Subject.setForeground(fgcolor); add(label_Subject); label_Subject.reshape(0, insets().top + 44, 50, 22); textField_Subject = new TextField(""); textField_Subject.setEditable(true); textField_Subject.setForeground(new Color(0, 0, 0)); textField_Subject.setBackground(new Color(255, 255, 255)); add(textField_Subject); int i1 = insets().left + 50; textField_Subject.reshape(i1, insets().top + 44, d.width - 50, 22); textArea_Msg = new TextArea(""); textArea_Msg.setEditable(true); textArea_Msg.setForeground(new Color(0, 0, 0)); textArea_Msg.setBackground(new Color(255, 255, 255)); add(textArea_Msg); textArea_Msg.reshape(0, insets().top + 66, d.width, d.height - 170); textArea_Log = new TextArea(""); textArea_Log.setEditable(true); textArea_Log.setForeground(new Color(0, 0, 0)); textArea_Log.setBackground(new Color(192, 192, 192)); add(textArea_Log); textArea_Log.reshape(0, d.height - 105, d.width, 80); button_Send = new Button("Send"); button_Send.setForeground(new Color(128, 0, 0)); button_Send.setBackground(new Color(192, 192, 192)); add(button_Send); button_Send.reshape(d.width / 2 - 105, d.height - 25, 70, 25); button_Clear = new Button("Clear"); button_Clear.setForeground(new Color(0, 128, 0)); button_Clear.setBackground(new Color(192, 192, 192)); add(button_Clear); button_Clear.reshape(d.width / 2 - 35, d.height - 25, 70, 25); button_ClearLog = new Button("Clear Log"); button_ClearLog.setForeground(new Color(0, 0, 128)); button_ClearLog.setBackground(new Color(192, 192, 192)); add(button_ClearLog); button_ClearLog.reshape(d.width / 2 + 35, d.height - 25, 70, 25); super.init(); } private final boolean SuperCedeEvent(Event event) { if(event.target == button_Send && event.id == 1001) { Button_SendClicked(event); return true; } if(event.target == button_Clear && event.id == 1001) { Button_ClearClicked(event); return true; } if(event.target != button_ClearLog || event.id != 1001) { return super.handleEvent(event); } else { Button_ClearLogClicked(event); return true; } } private final void SuperCedeStart(){} private final void SuperCedeStop() {} public WebSendMail() { // 发送邮件 param = new CommonApplet(); in_mailto = null; } // 成员变量 Color fgcolor; Color bgcolor; String host; Dimension d; CommonApplet param; String in_mailto; String in_website; Button button_Send; Label label_Subject; Label label3; TextField textField_Subject; TextField textField_From; TextField textField_To; TextArea textArea_Msg; Button button_Clear; Button button_ClearLog; Label label4; TextArea textArea_Log; }
