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我有一個程序有文本字段由用戶填寫。根據comboBox中選擇的內容，不同的字段是必需的。如果必填字段留空，我有一個錯誤處理程序。出於某種原因，我不斷收到姓氏，生日和depatermentName的錯誤。任何人都可以闡明爲什麼這些錯誤即使在這些字段有數據時也會彈出來嗎？文本字段拋出錯誤
這裏是我的代碼...
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.util.StringJoiner;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.JOptionPane;
import javax.swing.JComboBox;
@SuppressWarnings("serial")
public class AddEmployeeDisplay extends JFrame
{
private EmployeeQueries employeeQueries;
private JPanel displayPanel;
private JButton addEmpButton;
private JButton clearButton;
private JLabel firstNameLabel;
private JTextField firstNameText;
private JLabel lastNameLabel;
private JTextField lastNameText;
private JLabel SSNLabel;
private JTextField SSNText;
private JLabel birthdayLabel;
private JTextField birthdayText;
private JLabel employeeTypeLabel;
private JComboBox<String> employeeTypeCombo;
private JLabel departmentNameLabel;
private JTextField departmentNameText;
private JLabel grossSalesLabel;
private JTextField grossSalesText;
private JLabel commissionRateLabel;
private JTextField commissionRateText;
private JLabel baseSalaryLabel;
private JTextField baseSalaryText;
private JLabel bonusLabel;
private JTextField bonusText;
private JLabel hoursLabel;
private JTextField hoursText;
private JLabel wageLabel;
private JTextField wageText;
private JLabel weeklySalaryLabel;
private JTextField weeklySalaryText;
private static final String[] employeeType = {"", "BasePlusCommissionEmployee", "CommissionEmployee",
"HourlyEmployee", "SalariedEmployee"};
// Constructor
public AddEmployeeDisplay()
{
super("Add a New Employee");
// Establish database connection
employeeQueries = new EmployeeQueries();
// Create the GUI
displayPanel = new JPanel();
employeeTypeLabel = new JLabel();
employeeTypeCombo = new JComboBox<String>(employeeType);
employeeTypeCombo.setMaximumRowCount(5);
firstNameLabel = new JLabel();
firstNameText = new JTextField();
lastNameLabel = new JLabel();
lastNameText = new JTextField();
SSNLabel = new JLabel();
SSNText = new JTextField();
birthdayLabel = new JLabel();
birthdayText = new JTextField();
departmentNameLabel = new JLabel();
departmentNameText = new JTextField();
grossSalesLabel = new JLabel();
grossSalesText = new JTextField();
commissionRateLabel = new JLabel();
commissionRateText = new JTextField();
baseSalaryLabel = new JLabel();
baseSalaryText = new JTextField();
bonusLabel = new JLabel();
bonusText = new JTextField();
hoursLabel = new JLabel();
hoursText = new JTextField();
wageLabel = new JLabel();
wageText = new JTextField();
weeklySalaryLabel = new JLabel();
weeklySalaryText = new JTextField();
clearButton = new JButton();
addEmpButton = new JButton();
setLayout(new FlowLayout(FlowLayout.CENTER, 10, 10));
setSize(500, 600);
setResizable(false);
displayPanel.setLayout(new GridLayout(16, 5, 4, 4));
employeeTypeLabel.setText("Employee Type: ");
displayPanel.add(employeeTypeLabel);
displayPanel.add(employeeTypeCombo);
employeeTypeCombo.addItemListener(
new ItemListener()
{
public void itemStateChanged(ItemEvent event)
{
if(event.getStateChange() == ItemEvent.SELECTED)
{
if(employeeTypeCombo.getSelectedItem().toString() == "BasePlusCommissionEmployee")
{
firstNameText.setEditable(true);
lastNameText.setEditable(true);
SSNText.setEditable(true);
birthdayText.setEditable(true);
departmentNameText.setEditable(true);
grossSalesText.setEditable(true);
commissionRateText.setEditable(true);
baseSalaryText.setEditable(true);
bonusText.setEditable(true);
hoursText.setEditable(false);
wageText.setEditable(false);
weeklySalaryText.setEditable(false);
}
if(employeeTypeCombo.getSelectedItem().toString() == "CommissionEmployee")
{
firstNameText.setEditable(true);
lastNameText.setEditable(true);
SSNText.setEditable(true);
birthdayText.setEditable(true);
departmentNameText.setEditable(true);
grossSalesText.setEditable(true);
commissionRateText.setEditable(true);
baseSalaryText.setEditable(false);
bonusText.setEditable(true);
hoursText.setEditable(false);
wageText.setEditable(false);
weeklySalaryText.setEditable(false);
}
if(employeeTypeCombo.getSelectedItem().toString() == "HourlyEmployee")
{
firstNameText.setEditable(true);
lastNameText.setEditable(true);
SSNText.setEditable(true);
birthdayText.setEditable(true);
departmentNameText.setEditable(true);
grossSalesText.setEditable(false);
commissionRateText.setEditable(false);
baseSalaryText.setEditable(false);
bonusText.setEditable(true);
hoursText.setEditable(true);
wageText.setEditable(true);
weeklySalaryText.setEditable(false);
}
if(employeeTypeCombo.getSelectedItem().toString() == "SalariedEmployee")
{
firstNameText.setEditable(true);
lastNameText.setEditable(true);
SSNText.setEditable(true);
birthdayText.setEditable(true);
departmentNameText.setEditable(true);
grossSalesText.setEditable(false);
commissionRateText.setEditable(false);
baseSalaryText.setEditable(false);
bonusText.setEditable(true);
hoursText.setEditable(false);
wageText.setEditable(false);
weeklySalaryText.setEditable(true);
}
}
}
}
);
firstNameLabel.setText("First Name: ");
displayPanel.add(firstNameLabel);
displayPanel.add(firstNameText);
firstNameText.setEditable(false);
lastNameLabel.setText("Last Name: ");
displayPanel.add(lastNameLabel);
displayPanel.add(lastNameText);
lastNameText.setEditable(false);
SSNLabel.setText("SSN: ");
displayPanel.add(SSNLabel);
displayPanel.add(SSNText);
SSNText.setEditable(false);
birthdayLabel.setText("Birthday: ");
displayPanel.add(birthdayLabel);
displayPanel.add(birthdayText);
birthdayText.setEditable(false);
departmentNameLabel.setText("Department Name: ");
displayPanel.add(departmentNameLabel);
displayPanel.add(departmentNameText);
departmentNameText.setEditable(false);
grossSalesLabel.setText("Gross Sales: ");
displayPanel.add(grossSalesLabel);
displayPanel.add(grossSalesText);
grossSalesText.setEditable(false);
commissionRateLabel.setText("Commission Rate: ");
displayPanel.add(commissionRateLabel);
displayPanel.add(commissionRateText);
commissionRateText.setEditable(false);
baseSalaryLabel.setText("Base Salary: ");
displayPanel.add(baseSalaryLabel);
displayPanel.add(baseSalaryText);
baseSalaryText.setEditable(false);
bonusLabel.setText("Bonus Amount: ");
displayPanel.add(bonusLabel);
displayPanel.add(bonusText);
bonusText.setEditable(false);
hoursLabel.setText("Hours: ");
displayPanel.add(hoursLabel);
displayPanel.add(hoursText);
hoursText.setEditable(false);
wageLabel.setText("Wage: ");
displayPanel.add(wageLabel);
displayPanel.add(wageText);
wageText.setEditable(false);
weeklySalaryLabel.setText("Weekly Salary: ");
displayPanel.add(weeklySalaryLabel);
displayPanel.add(weeklySalaryText);
weeklySalaryText.setEditable(false);
add(displayPanel);
clearButton.setText("CLEAR");
clearButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
clearButtonActionPerformed(evt);
}
}
);
add(clearButton);
addEmpButton.setText("Add New Employee");
addEmpButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
addEmpButtonActionPerformed(evt);
}
}
);
add(addEmpButton);
addWindowListener(
new WindowAdapter()
{
public void windowClosing(WindowEvent evt)
{
employeeQueries.close();
System.exit(0);
}
}
);
setVisible(true);
}
private void clearButtonActionPerformed(ActionEvent e)
{
// Clear the fields so that a new entry may be made.
SSNText.setText("");
SSNText.setEditable(false);
firstNameText.setText("");
firstNameText.setEditable(false);
lastNameText.setText("");
lastNameText.setEditable(false);
birthdayText.setText("");
birthdayText.setEditable(false);
employeeTypeCombo.setSelectedItem("");
departmentNameText.setText("");
departmentNameText.setEditable(false);
grossSalesText.setText("");
grossSalesText.setEditable(false);
commissionRateText.setText("");
commissionRateText.setEditable(false);
baseSalaryText.setText("");
baseSalaryText.setEditable(false);
bonusText.setText("");
bonusText.setEditable(false);
hoursText.setText("");
hoursText.setEditable(false);
wageText.setText("");
wageText.setEditable(false);
weeklySalaryText.setText("");
weeklySalaryText.setEditable(false);
}
// Handles call when addEmpButton is clicked
private void addEmpButtonActionPerformed(ActionEvent evt)
{
int result = 0;
StringJoiner joiner = new StringJoiner(System.lineSeparator());
if (employeeTypeCombo.getSelectedItem().toString() == "")
joiner.add("Employee type missing.");
if(SSNText.getText() == "")
joiner.add("SSN missing.");
if(firstNameText.getText() == "")
joiner.add("First name missing.");
if(lastNameText.getText() == "");
joiner.add("Last name missing.");
if(birthdayText.getText() == "");
joiner.add("Birthday missing.");
if(departmentNameText.getText() == "");
joiner.add("Department name missing.");
if(joiner.length() != 0)
{
JOptionPane.showMessageDialog(this,
joiner.toString(),
"Error in input",
JOptionPane.PLAIN_MESSAGE);
return;
}
// Add base plus commission employee data to BasePlusCommissionEmployee table
if (employeeTypeCombo.getSelectedItem().toString() == "BasePlusCommissionEmployee")
{
if(grossSalesText.getText() == "")
joiner.add("Gross sales missing.");
if(commissionRateText.getText() == "")
joiner.add("Commission rate missing.");
if(baseSalaryText.getText() == "")
joiner.add("Base salary missing.");
if(bonusText.getText() == "")
joiner.add("Bonus missing.");
if(joiner.length() != 0)
{
JOptionPane.showMessageDialog(this,
joiner.toString(),
"Error in input",
JOptionPane.PLAIN_MESSAGE);
return;
}
result = 1;
employeeQueries.addBPCEmp(SSNText.getText(), grossSalesText.getText(), commissionRateText.getText(),
baseSalaryText.getText(), bonusText.getText());
}
// Add commission employee data to CommissionEmployee table
if (employeeTypeCombo.getSelectedItem().toString() == "CommissionEmployee")
{
if(grossSalesText.getText() == "")
joiner.add("Gross sales missing.");
if(commissionRateText.getText() == "")
joiner.add("Commission rate missing.");
if(bonusText.getText() == "")
joiner.add("Bonus missing.");
if(joiner.length() != 0)
{
JOptionPane.showMessageDialog(this,
joiner.toString(),
"Error in input",
JOptionPane.PLAIN_MESSAGE);
return;
}
result = 1;
employeeQueries.addCEmployee(SSNText.getText(), grossSalesText.getText(),
commissionRateText.getText(), bonusText.getText());
}
// Add hourly employee data to HourlyEmployee table
if (employeeTypeCombo.getSelectedItem().toString() == "HourlyEmployee")
{
if(hoursText.getText() == "")
joiner.add("Hours missing.");
if(wageText.getText() == "")
joiner.add("Wage missing.");
if(bonusText.getText() == "")
joiner.add("Bonus missing.");
if(joiner.length() != 0)
{
JOptionPane.showMessageDialog(this,
joiner.toString(),
"Error in input",
JOptionPane.PLAIN_MESSAGE);
return;
}
result = 1;
employeeQueries.addHEmployee(SSNText.getText(), hoursText.getText(),
wageText.getText(), bonusText.getText());
}
// Add salaried employee data to SalariedEmployee table
if (employeeTypeCombo.getSelectedItem().toString() == "SalariedEmployee")
{
if(weeklySalaryText.getText() == "")
joiner.add("Weekly salary missing.");
if(bonusText.getText() == "")
joiner.add("Bonus missing.");
if(joiner.length() != 0)
{
JOptionPane.showMessageDialog(this,
joiner.toString(),
"Error in input",
JOptionPane.PLAIN_MESSAGE);
return;
}
result = 1;
employeeQueries.addSEmployee(SSNText.getText(), weeklySalaryText.getText(), bonusText.getText());
}
// Add Employee data to Employee table
result += 1;
employeeQueries.addEmp(SSNText.getText(), firstNameText.getText(), lastNameText.getText(), birthdayText.getText(),
employeeTypeCombo.getSelectedItem().toString(), departmentNameText.getText());
if(result == 2)
JOptionPane.showMessageDialog(this, "Employee added!", "Employee added", JOptionPane.PLAIN_MESSAGE);
else
JOptionPane.showMessageDialog(this, "Employee not added!", "Error", JOptionPane.PLAIN_MESSAGE);
// Clear the fields so that a new entry may be made.
clearButtonActionPerformed(evt);
}
public static void main(String args[])
{
AddEmployeeDisplay addEmployeeDisplay = new AddEmployeeDisplay();
}
}
使用.equals比較字符串對象 –
'String'總是使用'string1.euals進行比較（字符串2 ）'，而不是'=='。而且，不用附加'WindowListener'，只需在'AddEmployeeDisplay'類的構造函數'setDefaultCloseOperation（JFrame.DISPOSE_ON_CLOSE）'中添加這行。並閱讀[併發在Swing]（https://docs.oracle.com/javase/tutorial/uiswing/concurrency/）。你啓動'Swing'應用程序的方式是值得懷疑的，因爲'Swing'要在'Event Disptacher Thread（EDT）'上啓動。 –