我正试图制作一个GUI，将十进制转换为二进制，反之亦然，但在public static void main（String args[]）上的表达式的开头非法。如何更正？
我的代码：
public class NewJFrame extends javax.swing.JFrame {
/**
* Creates new form NewJFrame
*/
public NewJFrame() {
setTitle("Quiz");
}
/**
* This method is called from within the constructor 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() {
jLabel1 = new javax.swing.JLabel();
jTextField1 = new javax.swing.JTextField();
jButton1 = new javax.swing.JButton();
jTextField2 = new javax.swing.JTextField();
jTextField3 = new javax.swing.JTextField();
jTextField4 = new javax.swing.JTextField();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
jComboBox1 = new javax.swing.JComboBox<>();
jTextField5 = new javax.swing.JTextField();
jLabel5 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jLabel1.setText("Desimal");
jTextField1.setText("jTextField1");
jButton1.setText("Konversikan");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jTextField2.setText("jTextField2");
jTextField3.setText("jTextField3");
jTextField4.setText("jTextField4");
jLabel2.setText("Biner");
jLabel3.setText("Hexa");
jLabel4.setText("Octal");
jComboBox1.setModel(new javax.swing.DefaultComboBoxModel<>(new String[] { "Desimal", "Biner", "Hexa", "Octal" }));
jTextField5.setText("jTextField5");
jLabel5.setText("Input");
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jLabel5)
.addGap(11, 11, 11)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addComponent(jTextField5, javax.swing.GroupLayout.PREFERRED_SIZE, 104, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(15, 15, 15)
.addComponent(jComboBox1, 0, 116, Short.MAX_VALUE)
.addGap(18, 18, 18)
.addComponent(jButton1))
.addGroup(layout.createSequentialGroup()
.addGap(22, 22, 22)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel4)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel1)
.addComponent(jLabel2))
.addGroup(layout.createSequentialGroup()
.addComponent(jLabel3)
.addGap(12, 12, 12)))
.addGap(26, 26, 26)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addComponent(jTextField2, javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jTextField4, javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jTextField3, javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jTextField1, javax.swing.GroupLayout.Alignment.LEADING, javax.swing.GroupLayout.PREFERRED_SIZE, 143, javax.swing.GroupLayout.PREFERRED_SIZE))))
.addGap(0, 0, Short.MAX_VALUE)))
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(31, 31, 31)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jComboBox1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jTextField5, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel5))
.addGap(53, 53, 53)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel1))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel2))
.addGap(24, 24, 24)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel3)
.addComponent(jTextField3, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jTextField4, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addComponent(jLabel4))
.addContainerGap(53, Short.MAX_VALUE))
);
pack();
}// </editor-fold>
private void error(){
jLabel2.setText("Input invalid");
jLabel1.setText("Input invalid");
jLabel3.setText("Input invalid");
jLabel4.setText("Input invalid");
}
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
if (jComboBox1.getSelectedItem() == "Desimal") {
try {
int decimal = Integer.parseInt(jTextField5.getText());
String biner = Integer.toBinaryString(decimal);
String hex = Integer.toHexString(decimal);
String octal = Integer.toOctalString(decimal);
jTextField1.setText(Integer.toString(decimal));
jTextField2.setText(biner);
jTextField3.setText(hex);
jTextField4.setText(octal);
} catch (Exception e) {
error();
}
}else if(jComboBox1.getSelectedItem() == "Biner")
try {
int decimal = Integer.parseInt(jTextField5.getText(), 2);
String biner = jTextField5.getText();
String hex = Integer.toHexString(decimal);
String octal = Integer.toOctalString(decimal);
jTextField1.setText(Integer.toString(decimal));
jTextField2.setText(biner);
jTextField3.setText(hex);
jTextField4.setText(octal);
} catch (Exception e){
}else if(jComboBox1.getSelectedItem() == "Biner")
try {
int decimal = Integer.parseInt(jTextField5.getText(), 16);
String biner = Integer.toBinaryString(decimal);
String octal = Integer.toOctalString(decimal);
jTextField1.setText(Integer.toString(decimal));
jTextField2.setText(biner);
jTextField3.setText(jTextField5.getText());
jTextField4.setText(octal);
} catch (Exception e) {
}else if(jComboBox1.getSelectedItem() == "Octal"){
try {
int decimal = Integer.parseInt(jTextField5.getText(),8);
String hexa = Integer.toHexString(decimal);
String biner = Integer.toBinaryString(decimal);
jTextField1.setText(Integer.toString(decimal));
jTextField2.setText(biner);
jTextField3.setText(hexa);
jTextField4.setText(jTextField5.getText());
} catch (Exception e) {
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(NewJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new NewJFrame().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton jButton1;
private javax.swing.JComboBox<String> jComboBox1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField2;
private javax.swing.JTextField jTextField3;
private javax.swing.JTextField jTextField4;
private javax.swing.JTextField jTextField5;
// End of variables declaration
}
修复您的语法错误。您忘记了主方法上方几行catch块的右括号，也忘记了其上方else-if的右括号。