Java源码——一个简单的数据库应用程序（通讯录）

无数据，不应用。现实生活中的很多系统都离不开数据库，而数据的增删改查则是最基本的功能。
这几天实现了以下个人在技术上的突破：
1. Java程序直连Oracle数据库，而之前的玩法是：
a. 直接使用Oracle Express Edition创建示例数据库应用程序 （好像用的是.NET）
b. 用Java连接MySQL和Derby (JavaDB)

2. 在JHTP教材示例的基础上，增加了两个删除记录和更新数据的功能，得益于：
a. 自己对SQL有了更深刻的理解，简单的PreparedStatement不在话下（呵呵）
b. 对Java程序的前后端交互有了完整的接触（之前写了很多小程序，没有打通数据库与代码交互的这一环节）

多说无益，分享代码如下：

1. PersonQueries类（用于通讯录程序所使用的PreparedStatement）

// Fig. 28.31: PersonQueries.java
// PreparedStatements used by the Address Book application
package ch24;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.List;
import java.util.ArrayList;

public class PersonQueries
{
private static final String URL = "jdbc:oracle:thin:@localhost:1521:orcl";
private static final String USERNAME = "c##scott";
private static final String PASSWORD = "scott";

private Connection connection; // manages connection
private PreparedStatement selectAllPeople;
private PreparedStatement selectPeopleByLastName;
private PreparedStatement insertNewPerson;
private PreparedStatement deletePerson;
private PreparedStatement updatePerson;

// constructor
public PersonQueries()
{
try
{
connection =
DriverManager.getConnection(URL, USERNAME, PASSWORD);

// create query that selects all entries in the AddressBook
selectAllPeople =
connection.prepareStatement("SELECT * FROM Addresses");

// create query that selects entries with a specific last name
selectPeopleByLastName = connection.prepareStatement(
"SELECT * FROM Addresses WHERE LastName = ?");

// create insert that adds a new entry into the database
insertNewPerson = connection.prepareStatement(
"INSERT INTO Addresses " +
"(AddressID, FirstName, LastName, Email, PhoneNumber)" +
"VALUES (id_sequence.nextval, ?, ?, ?, ?)");

// create delete statement that delete current entry from database
deletePerson = connection.prepareStatement(
"DELETE FROM Addresses where AddressID = ?");

// create update statement that delete current entry from database
updatePerson = connection.prepareStatement(
"UPDATE Addresses SET "+
"FirstName = ?, LastName = ?, Email = ?, PhoneNumber = ?" +
"WHERE AddressID = ?");
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
System.exit(1);
}
} // end PersonQueries constructor

// select all of the addresses in the database
public List< Person > getAllPeople()
{
List< Person > results = null;
ResultSet resultSet = null;

try
{
// executeQuery returns ResultSet containing matching entries
resultSet = selectAllPeople.executeQuery();
results = new ArrayList< Person >();

while (resultSet.next())
{
results.add(new Person(
resultSet.getInt("addressID"),
resultSet.getString("firstName"),
resultSet.getString("lastName"),
resultSet.getString("email"),
resultSet.getString("phoneNumber")));
}
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
}
finally
{
try
{
resultSet.close();
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
close();
}
}

return results;
}

// select person by last name
public List< Person > getPeopleByLastName(String name)
{
List< Person > results = null;
ResultSet resultSet = null;

try
{
selectPeopleByLastName.setString(1, name); // specify last name

// executeQuery returns ResultSet containing matching entries
resultSet = selectPeopleByLastName.executeQuery();

results = new ArrayList< Person >();

while (resultSet.next())
{
results.add(new Person(resultSet.getInt("addressID"),
resultSet.getString("firstName"),
resultSet.getString("lastName"),
resultSet.getString("email"),
resultSet.getString("phoneNumber")));
}
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
}
finally
{
try
{
resultSet.close();
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
close();
}
}

return results;
}

// add an entry
public int addPerson(
String fname, String lname, String email, String num)
{
int result = 0;

// set parameters, then execute insertNewPerson
try
{
insertNewPerson.setString(1, fname);
insertNewPerson.setString(2, lname);
insertNewPerson.setString(3, email);
insertNewPerson.setString(4, num);

// insert the new entry; returns # of rows updated
result = insertNewPerson.executeUpdate();
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
close();
}

return result;
}

// delete a person
public int deletePerson(
String addressID)
{
int result = 0;

// set parameters, then execute insertNewPerson
try
{
deletePerson.setString(1, addressID);

// insert the new entry; returns # of rows updated
result = deletePerson.executeUpdate();
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
close();
}

return result;
}

// update a person
public int updatePerson(
String fname, String lname, String email, String num, String addressID)
{
int result = 0;

// set parameters, then execute insertNewPerson
try
{
updatePerson.setString(1, fname);
updatePerson.setString(2, lname);
updatePerson.setString(3, email);
updatePerson.setString(4, num);
updatePerson.setString(5, addressID);

// update current entry; returns # of rows updated
result = updatePerson.executeUpdate();
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
close();
}

return result;
}

// close the database connection
public void close()
{
try
{
connection.close();
}
catch (SQLException sqlException)
{
sqlException.printStackTrace();
}
}
} // end class PersonQueries

2. AddressBookDisplay类（主程序，包括前端页面的及用户交互的定义）

// Fig. 28.32: AddressBookDisplay.java
// A simple address book
package ch24;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.util.List;
import javax.swing.JButton;
import javax.swing.Box;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.WindowConstants;
import javax.swing.BoxLayout;
import javax.swing.BorderFactory;
import javax.swing.JOptionPane;

public class AddressBookDisplay extends JFrame
{
private Person currentEntry;
private PersonQueries personQueries;
private List<Person> results;
private int numberOfEntries = 0;
private int currentEntryIndex;

private JButton browseButton;
private JLabel emailLabel;
private JTextField emailTextField;
private JLabel firstNameLabel;
private JTextField firstNameTextField;
private JLabel idLabel;
private JTextField idTextField;
private JTextField indexTextField;
private JLabel lastNameLabel;
private JTextField lastNameTextField;
private JTextField maxTextField;
private JButton nextButton;
private JLabel ofLabel;
private JLabel phoneLabel;
private JTextField phoneTextField;
private JButton previousButton;
private JButton queryButton;
private JLabel queryLabel;
private JPanel queryPanel;
private JPanel navigatePanel;
private JPanel displayPanel;
private JTextField queryTextField;
private JButton insertButton;
private JButton updateButton;
private JButton deleteButton;

// constructor
public AddressBookDisplay()
{
super("Address Book");

// establish database connection and set up PreparedStatements
personQueries = new PersonQueries();

// create GUI
navigatePanel = new JPanel();
previousButton = new JButton();
indexTextField = new JTextField(2);
ofLabel = new JLabel();
maxTextField = new JTextField(2);
nextButton = new JButton();
displayPanel = new JPanel();
idLabel = new JLabel();
idTextField = new JTextField(10);
firstNameLabel = new JLabel();
firstNameTextField = new JTextField(10);
lastNameLabel = new JLabel();
lastNameTextField = new JTextField(10);
emailLabel = new JLabel();
emailTextField = new JTextField(10);
phoneLabel = new JLabel();
phoneTextField = new JTextField(10);
queryPanel = new JPanel();
queryLabel = new JLabel();
queryTextField = new JTextField(10);
queryButton = new JButton();
browseButton = new JButton();
insertButton = new JButton();
updateButton = new JButton();
deleteButton = new JButton();

setLayout(new FlowLayout(FlowLayout.CENTER, 10, 10));
setSize(400, 355);
setResizable(false);

navigatePanel.setLayout(
new BoxLayout(navigatePanel, BoxLayout.X_AXIS));

previousButton.setText("Previous");
previousButton.setEnabled(false);
previousButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
previousButtonActionPerformed(evt);
}
}
); // end call to addActionListener

navigatePanel.add(previousButton);
navigatePanel.add(Box.createHorizontalStrut(10));

indexTextField.setHorizontalAlignment(
JTextField.CENTER);
indexTextField.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
indexTextFieldActionPerformed(evt);
}
}
); // end call to addActionListener

navigatePanel.add(indexTextField);
navigatePanel.add(Box.createHorizontalStrut(10));

ofLabel.setText("of");
navigatePanel.add(ofLabel);
navigatePanel.add(Box.createHorizontalStrut(10));

maxTextField.setHorizontalAlignment(
JTextField.CENTER);
maxTextField.setEditable(false);
navigatePanel.add(maxTextField);
navigatePanel.add(Box.createHorizontalStrut(10));

nextButton.setText("Next");
nextButton.setEnabled(false);
nextButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
nextButtonActionPerformed(evt);
}
}
); // end call to addActionListener

navigatePanel.add(nextButton);
add(navigatePanel);

displayPanel.setLayout(new GridLayout(5, 2, 4, 4));

idLabel.setText("Address ID:");
displayPanel.add(idLabel);

idTextField.setEditable(false);
displayPanel.add(idTextField);

firstNameLabel.setText("First Name:");
displayPanel.add(firstNameLabel);
displayPanel.add(firstNameTextField);

lastNameLabel.setText("Last Name:");
displayPanel.add(lastNameLabel);
displayPanel.add(lastNameTextField);

emailLabel.setText("Email:");
displayPanel.add(emailLabel);
displayPanel.add(emailTextField);

phoneLabel.setText("Phone Number:");
displayPanel.add(phoneLabel);
displayPanel.add(phoneTextField);
add(displayPanel);

queryPanel.setLayout(
new BoxLayout(queryPanel, BoxLayout.X_AXIS));

queryPanel.setBorder(BorderFactory.createTitledBorder(
"Find an entry by last name"));
queryLabel.setText("Last Name:");
queryPanel.add(Box.createHorizontalStrut(5));
queryPanel.add(queryLabel);
queryPanel.add(Box.createHorizontalStrut(10));
queryPanel.add(queryTextField);
queryPanel.add(Box.createHorizontalStrut(10));

queryButton.setText("Find");
queryButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
queryButtonActionPerformed(evt);
}
}
); // end call to addActionListener

queryPanel.add(queryButton);
queryPanel.add(Box.createHorizontalStrut(5));
add(queryPanel);

browseButton.setText("Browse All Entries");
browseButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
browseButtonActionPerformed(evt);
}
}
); // end call to addActionListener

add(browseButton);

insertButton.setText("Insert New Entry");
insertButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
insertButtonActionPerformed(evt);
}
}
); // end call to addActionListener

add(insertButton);

deleteButton.setText("Delete this Entry");
deleteButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
deleteButtonActionPerformed(evt);
}
}
); // end call to addActionListener

add(deleteButton);

updateButton.setText("Update this Entry");
updateButton.addActionListener(
new ActionListener()
{
public void actionPerformed(ActionEvent evt)
{
updateButtonActionPerformed(evt);
}
}
); // end call to addActionListener

add(updateButton);

addWindowListener(
new WindowAdapter()
{
public void windowClosing(WindowEvent evt)
{
personQueries.close(); // close database connection
System.exit(0);
}
}
); // end call to addWindowListener

setVisible(true);
} // end constructor

// handles call when previousButton is clicked
private void previousButtonActionPerformed(ActionEvent evt)
{
currentEntryIndex--;

if (currentEntryIndex < 0)
currentEntryIndex = numberOfEntries - 1;

indexTextField.setText("" + (currentEntryIndex + 1));
indexTextFieldActionPerformed(evt);
}

// handles call when nextButton is clicked
private void nextButtonActionPerformed(ActionEvent evt)
{
currentEntryIndex++;

if (currentEntryIndex >= numberOfEntries)
currentEntryIndex = 0;

indexTextField.setText("" + (currentEntryIndex + 1));
indexTextFieldActionPerformed(evt);
}

// handles call when queryButton is clicked
private void queryButtonActionPerformed(ActionEvent evt)
{
results =
personQueries.getPeopleByLastName(queryTextField.getText());
numberOfEntries = results.size();

if (numberOfEntries != 0)
{
currentEntryIndex = 0;
currentEntry = results.get(currentEntryIndex);
idTextField.setText("" + currentEntry.getAddressID());
firstNameTextField.setText(currentEntry.getFirstName());
lastNameTextField.setText(currentEntry.getLastName());
emailTextField.setText(currentEntry.getEmail());
phoneTextField.setText(currentEntry.getPhoneNumber());
maxTextField.setText("" + numberOfEntries);
indexTextField.setText("" + (currentEntryIndex + 1));
nextButton.setEnabled(true);
previousButton.setEnabled(true);
}
else
browseButtonActionPerformed(evt);
}

// handles call when a new value is entered in indexTextField
private void indexTextFieldActionPerformed(ActionEvent evt)
{
currentEntryIndex =
(Integer.parseInt(indexTextField.getText()) - 1);

if (numberOfEntries != 0 && currentEntryIndex < numberOfEntries)
{
currentEntry = results.get(currentEntryIndex);
idTextField.setText("" + currentEntry.getAddressID());
firstNameTextField.setText(currentEntry.getFirstName());
lastNameTextField.setText(currentEntry.getLastName());
emailTextField.setText(currentEntry.getEmail());
phoneTextField.setText(currentEntry.getPhoneNumber());
maxTextField.setText("" + numberOfEntries);
indexTextField.setText("" + (currentEntryIndex + 1));
}
}

// handles call when browseButton is clicked
private void browseButtonActionPerformed(ActionEvent evt)
{
try
{
results = personQueries.getAllPeople();
numberOfEntries = results.size();

if (numberOfEntries != 0)
{
currentEntryIndex = 0;
currentEntry = results.get(currentEntryIndex);
idTextField.setText("" + currentEntry.getAddressID());
firstNameTextField.setText(currentEntry.getFirstName());
lastNameTextField.setText(currentEntry.getLastName());
emailTextField.setText(currentEntry.getEmail());
phoneTextField.setText(currentEntry.getPhoneNumber());
maxTextField.setText("" + numberOfEntries);
indexTextField.setText("" + (currentEntryIndex + 1));
nextButton.setEnabled(true);
previousButton.setEnabled(true);
}
}
catch (Exception e)
{
e.printStackTrace();
}
}

// handles call when insertButton is clicked
private void insertButtonActionPerformed(ActionEvent evt)
{
int result = personQueries.addPerson(firstNameTextField.getText(),
lastNameTextField.getText(), emailTextField.getText(),
phoneTextField.getText());

if (result == 1)
JOptionPane.showMessageDialog(this, "Person added!",
"Person added", JOptionPane.PLAIN_MESSAGE);
else
JOptionPane.showMessageDialog(this, "Person not added!",
"Error", JOptionPane.PLAIN_MESSAGE);

browseButtonActionPerformed(evt);
}

// handles call when deleteButton is clicked
private void deleteButtonActionPerformed(ActionEvent evt)
{
int result = personQueries.deletePerson(idTextField.getText());

if (result == 1)
JOptionPane.showMessageDialog(this, "Person deleted!",
"Person deleted", JOptionPane.PLAIN_MESSAGE);
else
JOptionPane.showMessageDialog(this, "Person not deleted!",
"Error", JOptionPane.PLAIN_MESSAGE);

browseButtonActionPerformed(evt);
}

// handles call when updateButton is clicked
private void updateButtonActionPerformed(ActionEvent evt)
{
int result = personQueries.updatePerson(firstNameTextField.getText(),
lastNameTextField.getText(), emailTextField.getText(),
phoneTextField.getText(), idTextField.getText());

if (result == 1)
JOptionPane.showMessageDialog(this, "Person updated!",
"Person updated", JOptionPane.PLAIN_MESSAGE);
else
JOptionPane.showMessageDialog(this, "Person not updated!",
"Error", JOptionPane.PLAIN_MESSAGE);

browseButtonActionPerformed(evt);
}

// main method
public static void main(String args[])
{
new AddressBookDisplay();
}
} // end class AddressBookDisplay

程序运行效果：