我是Java初学者。我需要按字母顺序对名称字符串进行排序。字符串不是由用户提交的，而是从包含名字、姓氏和电话号码列表的文件中读取的。我也无法让删除功能正常工作。任何帮助将不胜感激。
请参阅下面的代码：
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.JOptionPane;
public class PhoneBook extends Frame implements ActionListener, ItemListener {
MenuItem newMI, openMI, saveMI, saveAsMI, exitMI;
MenuItem searchMI, deleteMI, updateMI, newEntryMI, sortMI;
String fileName;
List nameList, numberList;
TextField lastName, firstName, phoneNumber;
/**
* Constructor
*/
public PhoneBook() {
super("White Pages"); // set frame title
setLayout(new BorderLayout()); // set layout
// create menu bar
MenuBar menubar = new MenuBar();
setMenuBar(menubar);
// create file menu
Menu fileMenu = new Menu("File");
menubar.add(fileMenu);
newMI = fileMenu.add(new MenuItem("New"));
newMI.addActionListener(this);
openMI = fileMenu.add(new MenuItem("Open"));
openMI.addActionListener(this);
fileMenu.addSeparator();
saveMI = fileMenu.add(new MenuItem("Save"));
saveAsMI = fileMenu.add(new MenuItem("Save As ..."));
fileMenu.addSeparator();
exitMI = fileMenu.add(new MenuItem("Exit"));
exitMI.addActionListener(this);
// create edit menu
Menu editMenu = new Menu("Edit");
menubar.add(editMenu);
updateMI = editMenu.add(new MenuItem("Update"));
updateMI.addActionListener(this);
newEntryMI = editMenu.add(new MenuItem("New Entry"));
newEntryMI.addActionListener(this);
deleteMI = editMenu.add(new MenuItem("Delete"));
deleteMI.addActionListener(this);
editMenu.addSeparator();
searchMI = editMenu.add(new MenuItem("Search"));
searchMI.addActionListener(this);
sortMI = editMenu.add(new MenuItem("Sort"));
sortMI.addActionListener(this);
// create phone list and controls
Panel listPanel = new Panel(new BorderLayout());
add(listPanel, BorderLayout.CENTER);
Label label = new Label("Name List", Label.LEFT);
listPanel.add(label, BorderLayout.NORTH);
nameList = new List();
nameList.addItemListener(this);
numberList = new List();
listPanel.add(nameList, BorderLayout.CENTER);
Panel panel = new Panel(new BorderLayout());
add(panel, BorderLayout.WEST);
Panel editPanel = new Panel(new GridLayout(6, 1));
panel.add(editPanel, BorderLayout.NORTH);
label = new Label("Last Name", Label.LEFT);
editPanel.add(label);
lastName = new TextField();
editPanel.add(lastName);
label = new Label("First Name", Label.LEFT);
editPanel.add(label);
firstName = new TextField();
editPanel.add(firstName);
label = new Label("Phone Number", Label.LEFT);
editPanel.add(label);
phoneNumber = new TextField();
editPanel.add(phoneNumber);
}
// implementing ActionListener
public void actionPerformed(ActionEvent event) {
Object source = event.getSource();
if (source == newMI) {
nameList.removeAll();
numberList.removeAll();
fileName = null;
display(-1);
setTitle("White Pages"); // reset frame title
} else if (source == openMI) {
doOpen();
} else if (source == exitMI) {
System.exit(0);
} else if (source == updateMI) {
int index = nameList.getSelectedIndex();
String name = lastName.getText().trim() + " "
+ firstName.getText().trim();
String number = phoneNumber.getText().trim();
if (index < 0) { // add a new entry
nameList.add(name);
numberList.add(number);
nameList.select(nameList.getItemCount() - 1);
} else { // update an existing entry
nameList.replaceItem(name, index);
numberList.replaceItem(number, index);
nameList.select(index);
}
} else if (source == newEntryMI) {
nameList.select(-1);
display(-1);
}
else if (source == searchMI) {
String searchName = JOptionPane.showInputDialog(this,
"Please enter a name (last first) to search:");
System.out.println("Name to search: " + searchName);
}
}
/**
* Implementing ItemListener to display the selected entry
*/
public void itemStateChanged(ItemEvent event) {
display(nameList.getSelectedIndex());
}
/**
* method to specify and open a file
*/
private void doOpen() {
// display file selection dialog
FileDialog fDialog = new FileDialog(this, "Open ...", FileDialog.LOAD);
fDialog.setVisible(true);
// Get the file name chosen by the user
String file = fDialog.getFile();
// If user canceled file selection, return without doing anything.
if (file == null)
return;
fileName = fDialog.getDirectory() + file;
// Try to create a file reader from the chosen file.
FileReader reader;
try {
reader = new FileReader(fileName);
} catch (FileNotFoundException ex) {
JOptionPane.showMessageDialog(this, "File Not Found: " + fileName,
"Error", JOptionPane.ERROR_MESSAGE);
doOpen();
return;
}
BufferedReader bReader = new BufferedReader(reader);
// remove items from before if any
nameList.removeAll();
numberList.removeAll();
// Try to read from the input file one line at a time.
try {
int index;
String name, number;
String textLine = bReader.readLine();
while (textLine != null) {
index = textLine.indexOf((int) ',');
if (index > 0) {
name = textLine.substring(0, index);
number = textLine.substring(index + 1);
nameList.add(name.trim());
numberList.add(number.trim());
}
textLine = bReader.readLine();
}
bReader.close();
reader.close();
} catch (IOException ioe) {
JOptionPane.showMessageDialog(this,
"Error reading file: " + ioe.toString(), "Error",
JOptionPane.ERROR_MESSAGE);
return;
}
setTitle("White Pages: " + file); // reset frame title
nameList.select(0);
display(0);
}
/**
* method to display the current entry
*/
private void display(int index) {
if (index < 0) {
lastName.setText("");
firstName.setText("");
phoneNumber.setText("");
} else {
String name = nameList.getItem(index);
int space = name.indexOf((int) ' ');
lastName.setText(name.substring(0, space));
firstName.setText(name.substring(space + 1));
phoneNumber.setText(numberList.getItem(index));
}
}
/**
* the main method
*/
public static void main(String[] argv) {
// create frame
System.out.println("Creating window ... ");
PhoneBook frame = new PhoneBook();
Dimension size = Toolkit.getDefaultToolkit().getScreenSize();
frame.setSize(size.width / 2, size.height / 2);
frame.setLocation(100, 100);
System.out.println("Your Screen Size: " + size.width + " (width) x "
+ size.height + " (height)");
// add window closing listener
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
// show the frame
frame.setVisible(true);
}
}