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Java applet RuntimeException（java.lang.NoClassDefFoundError：javax / mail / Authenticator）

IT知识AuthenticatoException

金鞍玉勒寻芳客，未信我庐别有春。这篇文章主要讲述Java applet RuntimeException：java.lang.NoClassDefFoundError：javax / mail / Authenticator相关的知识，希望能为你提供帮助。
我编写了我的第一个java applet，并在我的Web服务器上部署它时遇到错误。我的applet使用了几个额外的jar文件，如javaMail mail.jar，smtp.jar，mailapi.jar等。当我尝试在Web浏览器中显示我的applet时，我在错误对话框中获得了这样的信息：

java.lang.RuntimeException: java.lang.NoClassDefFoundError: javax/mail/Authenticator .. Caused by: java.lang.NoClassDefFoundError: javax/mail/Authenticator ... 20 more

我对Web应用程序不是很好，也不确定导致此错误的原因。从信息我假设我的applet无法加载库。那我怎么解决这个问题呢？我在/ lib目录下的服务器上有这些库。所有其他文件都在主目录中。我的html文件如下：
< HTML> < HEAD> < TITLE> TPSA Speed Test< /TITLE> < /HEAD> < BODY> < P> < APPLET code="speedtester_pkg/AppletMain.class" archive="SpeedTester.jar" width=440height=600> < /APPLET> < /P> < /BODY> < /HTML>

我还尝试使用JNLP将我的applet加载到Web浏览器，效果相同。我试图找到一些方法将这些库指向HTML文件，但我没有管理（试图在JNLP文件中添加另一个jar存档行或nativelib）。我还试图用我的applet类将这些库添加到jar文件中，但这也无济于事。
这是我的代码，我在代码的末尾使用javaMail（sendTestResults（）方法）：
/* * AppletMain.java */ package speedtester_pkg; import java.awt.*; import java.beans.*; import java.io.*; import java.util.*; import java.util.logging.*; import javax.swing.*; import javax.mail.Address; import javax.mail.Message; import javax.mail.MessagingException; import javax.mail.PasswordAuthentication; import javax.mail.Session; import javax.mail.Transport; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage; public class AppletMain extends javax.swing.JApplet implements PropertyChangeListener{private ArrayList< String> customerFields; private DataReader dataReader; private Test test; private FileHandler fh; private ProgressBarTask progressBarTask; private JTextField[] customerData; private String speed, cpuLoad, NICspeed, testTime; private int timeDef = 60; /** * The input file directory */ //public String directory = "C:\Documents and Settings\Administrator\Pulpit\"; public String filename = "speedtestData.txt"; /** * Input file should bea simple "*.txt" file named "speedtestData.txt" */ public File file; // mail sending data /** * TO DO encrypt mailing data */ private String smtpHost = "smtp.gmail.com", username = "myUserName", password = "myPassword"; private int port = 465; // TLS 587/ SSL 465/** Initializes the applet Applet */ @Override public void init() { try { java.awt.EventQueue.invokeAndWait(new Runnable() { public void run() { createGUI(); } }); } catch (Exception ex) { ex.printStackTrace(); } }/** This method is called from within the init() method to * initialize the form. * WARNING: Do NOT modify this code. The content of this method is * always regenerated by the Form Editor. */ @SuppressWarnings("unchecked") // < editor-fold defaultstate="collapsed" desc="Generated Code"> private void initComponents() {infoPanel = new javax.swing.JPanel(); labelLogo = new javax.swing.JLabel(); labelTitle = new javax.swing.JLabel(); labelLinkSpeed = new javax.swing.JLabel(); labelProcessorLoad = new javax.swing.JLabel(); labelNIC = new javax.swing.JLabel(); buttonStart = new javax.swing.JButton(); jLabel4 = new javax.swing.JLabel(); jLabel5 = new javax.swing.JLabel(); jLabel6 = new javax.swing.JLabel(); jProgressBar = new javax.swing.JProgressBar(); formPanel = new javax.swing.JPanel(); jLabel8 = new javax.swing.JLabel(); buttonSend = new javax.swing.JButton(); labelForm = new javax.swing.JLabel(); infoLabel = new javax.swing.JLabel(); jScrollPane = new javax.swing.JScrollPane(); commentText = new javax.swing.JTextArea(); labelTitle.setFont(new java.awt.Font("Tahoma", 1, 14)); // NOI18N labelTitle.setHorizontalAlignment(javax.swing.SwingConstants.CENTER); labelTitle.setText("Link Speed Test"); labelLinkSpeed.setFont(new java.awt.Font("Tahoma", 1, 24)); // NOI18N labelLinkSpeed.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT); labelProcessorLoad.setFont(new java.awt.Font("Tahoma", 1, 18)); // NOI18N labelProcessorLoad.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT); labelNIC.setFont(new java.awt.Font("Tahoma", 0, 14)); // NOI18N labelNIC.setHorizontalAlignment(javax.swing.SwingConstants.RIGHT); buttonStart.setText("Start"); buttonStart.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { buttonStartActionPerformed(evt); } }); jLabel4.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N jLabel4.setText("Szybko?? ??cza:"); jLabel5.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N jLabel5.setText("Obci??enie procesora:"); jLabel6.setFont(new java.awt.Font("Tahoma", 0, 12)); // NOI18N jLabel6.setText("Szybko?? karty sieciowej:"); javax.swing.GroupLayout infoPanelLayout = new javax.swing.GroupLayout(infoPanel); infoPanel.setLayout(infoPanelLayout); infoPanelLayout.setHorizontalGroup( infoPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, infoPanelLayout.createSequentialGroup() .addComponent(labelLogo, javax.swing.GroupLayout.PREFERRED_SIZE, 100, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(infoPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING) .addGroup(infoPanelLayout.createSequentialGroup() .addGroup(infoPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(jLabel5) .addComponent(jLabel6) .addComponent(jLabel4)) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(infoPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(labelLinkSpeed, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 146, Short.MAX_VALUE) .addComponent(labelProcessorLoad, javax.swing.GroupLayout.DEFAULT_SIZE, 146, Short.MAX_VALUE) .addComponent(labelNIC, javax.swing.GroupLayout.DEFAULT_SIZE, 146, Short.MAX_VALUE))) .addComponent(labelTitle, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.PREFERRED_SIZE, 289, javax.swing.GroupLayout.PREFERRED_SIZE)) .addGap(22, 22, 22)) .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, infoPanelLayout.createSequentialGroup() .addContainerGap(352, Short.MAX_VALUE) .addComponent(buttonStart, javax.swing.GroupLayout.PREFERRED_SIZE, 65, javax.swing.GroupLayout.PREFERRED_SIZE)) ); infoPanelLayout.setVerticalGroup( infoPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGroup(infoPanelLayout.createSequentialGroup() .addContainerGap() .addGroup(infoPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false) .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, infoPanelLayout.createSequentialGroup() .addComponent(labelTitle) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(infoPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING) .addComponent(jLabel4, javax.swing.GroupLayout.PREFERRED_SIZE, 31, javax.swing.GroupLayout.PREFERRED_SIZE) .addComponent(labelLinkSpeed, javax.swing.GroupLayout.DEFAULT_SIZE, 31, Short.MAX_VALUE)) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(infoPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(jLabel5) .addComponent(labelProcessorLoad, javax.swing.GroupLayout.PREFERRED_SIZE, 21, javax.swing.GroupLayout.PREFERRED_SIZE)) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addGroup(infoPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(jLabel6) .addComponent(labelNIC, javax.swing.GroupLayout.PREFERRED_SIZE, 18, javax.swing.GroupLayout.PREFERRED_SIZE)) .addGap(6, 6, 6)) .addGroup(infoPanelLayout.createSequentialGroup() .addGap(16, 16, 16) .addComponent(labelLogo, javax.swing.GroupLayout.PREFERRED_SIZE, 100, javax.swing.GroupLayout.PREFERRED_SIZE))) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 8, Short.MAX_VALUE) .addComponent(buttonStart) .addContainerGap()) ); javax.swing.GroupLayout formPanelLayout = new javax.swing.GroupLayout(formPanel); formPanel.setLayout(formPanelLayout); formPanelLayout.setHorizontalGroup( formPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 417, Short.MAX_VALUE) ); formPanelLayout.setVerticalGroup( formPanelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 127, Short.MAX_VALUE) ); jLabel8.setText("Uwagi:"); buttonSend.setText("Wy?lij"); buttonSend.addActionListener(new java.awt.event.ActionListener() { public void actionPerformed(java.awt.event.ActionEvent evt) { buttonSendActionPerformed(evt); } }); labelForm.setFont(new java.awt.Font("Tahoma", 0, 14)); labelForm.setText("Formularz:"); infoLabel.setFont(new java.awt.Font("Tahoma", 1, 12)); // NOI18N infoLabel.setHorizontalAlignment(javax.swing.SwingConstants.CENTER); infoLabel.setText("Kliknij przycisk "Start" aby rozpocz?? test"); commentText.setColumns(20); commentText.setRows(5); jScrollPane.setViewportView(commentText); javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane()); getContentPane().setLayout(layout); layout.setHorizontalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 437, Short.MAX_VALUE) .addGap(0, 437, Short.MAX_VALUE) .addGroup(layout.createSequentialGroup() .addContainerGap() .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addComponent(jScrollPane, javax.swing.GroupLayout.DEFAULT_SIZE, 417, Short.MAX_VALUE) .addComponent(formPanel, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) .addComponent(infoLabel, javax.swing.GroupLayout.DEFAULT_SIZE, 417, Short.MAX_VALUE) .addComponent(jLabel8, javax.swing.GroupLayout.PREFERRED_SIZE, 42, javax.swing.GroupLayout.PREFERRED_SIZE) .addComponent(jProgressBar, javax.swing.GroupLayout.DEFAULT_SIZE, 417, Short.MAX_VALUE) .addComponent(infoPanel, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE) .addComponent(labelForm) .addComponent(buttonSend, javax.swing.GroupLayout.Alignment.TRAILING)) .addContainerGap()) ); layout.setVerticalGroup( layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING) .addGap(0, 572, Short.MAX_VALUE) .addGap(0, 572, Short.MAX_VALUE) .addGroup(layout.createSequentialGroup() .addComponent(infoPanel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) .addComponent(jProgressBar, javax.swing.GroupLayout.PREFERRED_SIZE, 19, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(infoLabel, javax.swing.GroupLayout.PREFERRED_SIZE, 29, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED) .addComponent(labelForm) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(formPanel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(jLabel8, javax.swing.GroupLayout.PREFERRED_SIZE, 16, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(jScrollPane, javax.swing.GroupLayout.PREFERRED_SIZE, 109, javax.swing.GroupLayout.PREFERRED_SIZE) .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED) .addComponent(buttonSend) .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)) ); }// < /editor-fold> public void createGUI() { try { dataReader = new DataReader(this); dataReader.read(); customerFields = dataReader.getCustomerFields(); testTime = String.valueOf(dataReader.getTestTime()); initComponents(); generateCustomerForm(); test = new Test(this, dataReader.getDownloadURLs(), dataReader.getTestTime()); } catch (ClassNotFoundException ex) { Logger.getLogger(AppletMain.class.getName()).log(Level.SEVERE, null, ex); } catch (InstantiationException ex) { Logger.getLogger(AppletMain.class.getName()).log(Level.SEVERE, null, ex); } catch (IllegalAccessException ex) { Logger.getLogger(AppletMain.class.getName()).log(Level.SEVERE, null, ex); } catch (UnsupportedLookAndFeelException ex) { Logger.getLogger(AppletMain.class.getName()).log(Level.SEVERE, null, ex); } catch (FileNotFoundException ex) { Logger.getLogger(AppletMain.class.getName()).log(Level.SEVERE, null, ex); }}private void buttonStartActionPerformed(java.awt.event.ActionEvent evt) { buttonStart.setEnabled(false); infoLabel.setText("Poczekaj do końca testu..."); progressBarTask = new ProgressBarTask(this); infoLabel.setText("progress bar"); progressBarTask.addPropertyChangeListener(this); progressBarTask.execute(); Thread testThread = new Thread(this.test); testThread.start(); System.out.println("Test thread "" + testThread.getName() + "" started."); }private void buttonSendActionPerformed(java.awt.event.ActionEvent evt) { try { sendTestResults(); } catch (MessagingException ex) { Logger.getLogger(AppletMain.class.getName()).log(Level.SEVERE, null, ex); } catch (UnsupportedEncodingException ex) { Logger.getLogger(AppletMain.class.getName()).log(Level.SEVERE, null, ex); }}private void generateCustomerForm() throws ClassNotFoundException, InstantiationException, IllegalAccessException, UnsupportedLookAndFeelException { UIManager.setLookAndFeel(UIManager.getCrossPlatformLookAndFeelClassName()); //correcting auto-generated layout jLabel8.setFont(new java.awt.Font("Tahoma", 0, 11)); labelProcessorLoad.setAlignmentX(RIGHT_ALIGNMENT); labelLogo.setIcon(new ImageIcon(getImage(getDocumentBase(), "orange.jpeg"))); //gereate JLabels and JTextFields read from file GridBagLayout gridBagLayout = new GridBagLayout(); GridBagConstraints gbc = new GridBagConstraints(); formPanel.setLayout(gridBagLayout); customerData = https://www.songbingjia.com/android/new JTextField[customerFields.size()]; for(int i=0; i< customerFields.size(); i++) { JLabel l = new JLabel(customerFields.get(i)); l.setFont(new java.awt.Font("Tahoma", 0, 11)); gbc.fill = GridBagConstraints.HORIZONTAL; gbc.gridx=0; gbc.gridy=i; gbc.weightx = 0.5; gbc.weighty = 0.5; formPanel.add(l, gbc); JTextField t = new JTextField(); t.setFont(new java.awt.Font("Tahoma", 0, 11)); gbc.fill = GridBagConstraints.HORIZONTAL; gbc.gridx=1; gbc.gridy=i; gbc.weightx = 0.5; gbc.weighty = 0.5; formPanel.add(t, gbc); customerData[i] = t; }}/** * Invoked when task's progress property changes. */ public void propertyChange(PropertyChangeEvent evt) { if (evt.getPropertyName().equals("progress")) { int progress = (Integer) evt.getNewValue(); jProgressBar.setValue(progress); } }public void setLabelProcessorLoad(String text) { labelProcessorLoad.setText(text); }public void setLabelLinkSpeed(String text) { labelLinkSpeed.setText(text); }public void setLabelNIC(String text) { labelNIC.setText(text); }public JProgressBar getProgressBar() { return jProgressBar; }public JButton getButtonStart() { return buttonStart; }public Test getTest() { return this.test; }public void setNICspeed(String NICspeed) { this.NICspeed = NICspeed; }public void setCpuLoad(String cpuLoad) { this.cpuLoad = cpuLoad; }public void setSpeed(String speed) { this.speed = speed; }public JLabel getInfoLabel() { return infoLabel; } /** * Prepares e-mail message for sending via google SMTP protocol with SSL */ private void sendTestResults() throws MessagingException, UnsupportedEncodingException{ Properties props = new Properties(); props.put("mail.smtp.host", "smtp.gmail.com"); props.put("mail.smtp.socketFactory.port", "465"); props.put("mail.smtp.socketFactory.class", "javax.net.ssl.SSLSocketFactory"); props.put("mail.smtp.auth", "true"); props.put("mail.smtp.port", "465"); Session session = Session.getDefaultInstance(props, new javax.mail.Authenticator() { protected PasswordAuthentication getPasswordAuthentication() { return new PasswordAuthentication(username,password); } }); MimeMessage message = new MimeMessage(session); //Setting message fields Address toAddress = new InternetAddress(dataReader.getMail(), "SpeedTest crew"); message.addRecipient(Message.RecipientType.TO, toAddress); message.setSubject("SpeedTest"); message.setText(prepareMailText(), "UTF8"); Transport.send(message); infoLabel.setText("Wiadomo?? z wynikami testu zosta?a wys?ana pomy?lnie"); System.out.println("Mail sent."); }/** * Gets all test results and customer data and prepares mail content * @return the content of e-mail body */ private String prepareMailText() { String messageContentHeader = "Pr?dko?? pobierania " + "Obci??enie procesora " + "Szybko?? ??cza karty sieciowej " + "Czas trwania testu "; String messageContent = speed + " "+ cpuLoad + " " + NICspeed + " " + testTime + " "; for(int j=0; j< customerData.length; j++) { messageContentHeader += customerFields.get(j) + " "; messageContent += customerData[j].getText() + " "; } messageContentHeader += "Uwagi"; messageContent += commentText.getText(); String messageText = messageContentHeader + " " + messageContent; return messageText; }// Variables declaration - do not modify private javax.swing.JButton buttonSend; private javax.swing.JButton buttonStart; private javax.swing.JTextArea commentText; private javax.swing.JPanel formPanel; private javax.swing.JLabel infoLabel; private javax.swing.JPanel infoPanel; private javax.swing.JLabel jLabel4; private javax.swing.JLabel jLabel5; private javax.swing.JLabel jLabel6; private javax.swing.JLabel jLabel8; private javax.swing.JProgressBar jProgressBar; private javax.swing.JScrollPane jScrollPane; private javax.swing.JLabel labelForm; private javax.swing.JLabel labelLinkSpeed; private javax.swing.JLabel labelLogo; private javax.swing.JLabel labelNIC; private javax.swing.JLabel labelProcessorLoad; private javax.swing.JLabel labelTitle; // End of variables declaration}

我也遇到了像Sigar.jar这样的其他库的问题，但我想它会解决类似问题。
有人有好的建议吗？
答案有必要将包含javax.mail包的Jar添加到applet的运行时类路径中。要实现这一点（一种方法）将jar放在同一个地方SpeedTester.jar并更改存档属性：
archive="SpeedTester.jar"

..至：
archive="SpeedTester.jar,mail.jar"

更新1更改整个applet元素：
From
< APPLET code="speedtester_pkg/AppletMain.class" archive="SpeedTester.jar" width=440 height=600> < /APPLET>

To
< APPLET code="speedtester_pkg.AppletMain" archive="SpeedTester.jar,mail.jar" width=440 height=600> < /APPLET>

假设applet类的包是speedtester_pkg，applet名为AppletMain。 code属性应该是applet类的完全限定名，而不是路径/文件名。
更新2以上建议重新开始。 mail.jar不考虑Test，DataReader或ProgressBarTask（或他们加载的类）中引用的类。使用archive属性“冲洗并重复”有关向运行时类路径添加额外API的建议。
Note
似乎其他答案指的是一个网络应用程序。这完全是服务器端的。对于这样的网络应用程序，将Jars放入lib是有道理的。 OTOH小程序只能通过将Jar的URL复制/粘贴到浏览器地址栏并按Enter键来访问可用的Jar。
事实上，使用Jar的代码库和href的组合，对于applet是否能够访问存档是一个很好的“酸测试”。
另一答案看起来你错过了javax.mail.Authenticator的JAR
您可以使用FindJar站点来确定JAR的名称以及下载位置。谷歌为它; 值得了解的。
你可能也会错过其他人。继续将JAR添加到应用程序的WEB-INF / lib中，直到CNF异常消失为止。
另一答案【Java applet RuntimeException（java.lang.NoClassDefFoundError：javax / mail / Authenticator）】缺少JAR（在您的情况下为mail.jar）是任何ClassNotFoundexception的主要原因。将它放在您的应用服务器lib目录中以解决此问题。

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