Create a form, to achieve all the letters in the string is converted to uppercase or lowercase, as follows:
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
import javax.swing.UIManager;
public class Example extends JFrame {
private JTextField inputTextField;
private JTextField outputTextField;
private final ButtonGroup buttonGroup = new ButtonGroup();
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Example frame = new Example();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
//Create the frame.
public Example() {
setTitle("字符串大小写转换");
setBounds(100, 100, 450, 250);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setLayout(null);
inputTextField = new JTextField();
inputTextField.setBounds(23, 21, 383, 31);
getContentPane().add(inputTextField);
inputTextField.setColumns(10);
JButton button = new JButton("\u8F6C\u6362");//转换
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
do_button_actionPerformed(arg0);
}
});
button.setBounds(23, 77, 93, 23);
getContentPane().add(button);
JRadioButton radioButton = new JRadioButton("大写");
radioButton.setActionCommand("大写");
radioButton.setSelected(true);
radioButton.setBounds(169, 77, 76, 23);
buttonGroup.add(radioButton);
getContentPane().add(radioButton);
JRadioButton radioButton_1 = new JRadioButton("小写");
radioButton_1.setBounds(280, 77, 121, 23);
radioButton_1.setActionCommand("小写");
buttonGroup.add(radioButton_1);
getContentPane().add(radioButton_1);
outputTextField = new JTextField();
outputTextField.setEditable(false);
outputTextField.setColumns(10);
outputTextField.setBounds(23, 122, 383, 31);
getContentPane().add(outputTextField);
@SuppressWarnings("unused")
String strBook = "MingRiBook".toLowerCase();
}
protected void do_button_actionPerformed(ActionEvent arg0) {
// 获取大小写单选项的选择
String command = buttonGroup.getSelection().getActionCommand();
boolean upper = command.equals("大写");// 判断是否选择的大写单选项
String text = inputTextField.getText();// 获取输入字符串
if (upper) {// 大写转换
outputTextField.setText(text.toUpperCase());
} else {// 小写转换
outputTextField.setText(text.toLowerCase());
}
}
}
Execution results as shown below: