JTextField textField = new JTextField(20);
// 添加到JFrame中...

// 获取文本内容
String text = textField.getText();

JPasswordField passwordField = new JPasswordField(20);
// 添加到JFrame中...

// 获取密码(返回char数组)
char[] password = passwordField.getPassword();
// 如果需要字符串形式
String passwordStr = new String(password);

JTextArea textArea = new JTextArea(5, 20);
// 添加到JFrame中...

// 获取文本内容
String text = textArea.getText();

JComboBox<String> comboBox = new JComboBox<>(new String[]{"选项1", "选项2", "选项3"});
// 添加到JFrame中...

// 获取选中的项
String selectedItem = (String) comboBox.getSelectedItem();

JCheckBox checkBox = new JCheckBox("选择我");
// 添加到JFrame中...

// 获取是否被选中
boolean isSelected = checkBox.isSelected();

JRadioButton radio1 = new JRadioButton("选项1");
JRadioButton radio2 = new JRadioButton("选项2");
ButtonGroup group = new ButtonGroup();
group.add(radio1);
group.add(radio2);
// 添加到JFrame中...

// 获取选中的单选按钮
boolean radio1Selected = radio1.isSelected();
boolean radio2Selected = radio2.isSelected();

JList<String> list = new JList<>(new String[]{"项目1", "项目2", "项目3"});
// 添加到JFrame中...

// 获取选中的项
String selectedValue = list.getSelectedValue();
// 或者获取多个选中的项(如果允许多选)
List<String> selectedValues = list.getSelectedValuesList();

JButton submitButton = new JButton("提交");
submitButton.addActionListener(e -> {
    String text = textField.getText();
    System.out.println("获取到的文本: " + text);
});

String text = textField.getText();
if (text == null || text.trim().isEmpty()) {
    JOptionPane.showMessageDialog(frame, "请输入有效内容");
    return;
}

SwingUtilities.invokeLater(() -> {
    // 在这里更新UI或获取UI数据
});