我开发了一个java应用程序，它会在加载窗口后系统打开时自动调用。系统用户必须输入有关他的详细信息并访问计算机。该应用程序将消失并在后台运行。现在当他关闭系统时，后台应用程序将停止，在停止时我想捕获事件并更新状态作为我的数据库中的注销。是否有捕获事件的功能。
package userauth;
import java.awt.Cursor;
import java.awt.SystemColor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.io.IOException;
import java.net.InetAddress;
import java.net.URISyntaxException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
import javax.swing.text.AbstractDocument;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.DocumentFilter;
class Home
{
static JFrame frame,frame1;
static String facname,stdid;
Home() throws IOException,URISyntaxException
{
frame = new JFrame("Application");
frame.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
frame.setUndecorated(true);
frame.setAlwaysOnTop(true);
JPanel contentPane = new JPanel();
contentPane.setOpaque(true);
contentPane.setBackground(SystemColor.activeCaption);
contentPane.setLayout(null);
java.net.URL url = Home.class.getResource("/fac.png");
ImageIcon facimage = new ImageIcon(url);
JLabel faclab = new JLabel(facimage);
faclab.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
faclab.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() > 0) {
facframe();
}
}
});
java.net.URL url1 = Home.class.getResource("/user.png");
ImageIcon stuimage = new ImageIcon(url1);
JLabel stulab = new JLabel(stuimage);
stulab.setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
stulab.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent e) {
if (e.getClickCount() > 0) {
studentframe();
}
}
});
JLabel facl=new JLabel("Faculty");
facl.setHorizontalAlignment(SwingConstants.CENTER);
JLabel stdl=new JLabel("Student");
stdl.setHorizontalAlignment(SwingConstants.CENTER);
faclab.setBounds(450,250, 200, 200);
stulab.setBounds(800,250, 200, 200);
facl.setBounds(450, 475, 200, 20);
stdl.setBounds(800,475,200,20);
contentPane.add(faclab);
contentPane.add(stulab);
contentPane.add(facl);
contentPane.add(stdl);
frame.setContentPane(contentPane);
frame.setSize(1500, 1000);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
protected static void facframe()
{
frame1 = new JFrame("Faculty");
frame1.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
frame1.setUndecorated(true);
frame1.setAlwaysOnTop(true);
JPanel contentPane = new JPanel();
contentPane.setOpaque(true);
contentPane.setBackground(SystemColor.activeCaption);
contentPane.setLayout(null);
JLabel facnamefieldl=new JLabel("Faculty Name");
JLabel deptlabel=new JLabel("Department");
deptlabel.setBounds(400, 380, 140, 25);
contentPane.add(deptlabel);
facnamefieldl.setBounds(400, 350, 140, 25);
contentPane.add(facnamefieldl);
JTextField facname = new JTextField("");
facname.setBounds(560, 350,200, 25);
String depts[]={"Select Dept","Automobile","Mechanical(Btech)","Civil(Btech)","IT","CSE","ECE","EEE","MBA","Training","Mechanical(Poly tech.)","Civil(Poly tech.)","EEE(Poly tech.)"};
JComboBox deptnames=new JComboBox(depts);
deptnames.setBounds(560,380,150,25);
JButton submit=new JButton("Submit");
JButton back=new JButton("Back");
submit.setLayout(null);
back.setBounds(560,445 , 80, 25);
submit.setBounds(560,415 , 80, 25);
contentPane.add(deptnames);
contentPane.add(back);
contentPane.add(facname);
contentPane.add(submit);
frame1.setSize(1500, 1000);
frame1.setContentPane(contentPane);
frame1.setLocationRelativeTo(null);
frame1.setVisible(true);
frame.setVisible(false);
back.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
frame1.setVisible(false);
frame.setVisible(true);
}
});
submit.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
facins(facname.getText(),deptnames.getSelectedItem().toString());
}
});
}
protected static void facins(String fname,String dept)
{
try
{
InetAddress ip=InetAddress.getLocalHost();
String hostname=ip.getHostName();
String str=ip.toString();
facname=fname;
String ipaddress=str.substring(str.indexOf("/")+1);
if (fname.equals("")||dept.equals("Select Dept")){
frame1.setAlwaysOnTop(false);
JOptionPane.showMessageDialog(null, "please fill all the fields");
frame1.setAlwaysOnTop(true);
}
else
{
Class.forName("com.mysql.jdbc.Driver");
Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/userauth","root","");
PreparedStatement stmt=conn.prepareStatement("insert into faculty(facname,dept,ipaddress,hostname,date)values(?,?,?,?,NOW())");
stmt.setString(1, fname);
stmt.setString(2, dept);
stmt.setString(3, ipaddress);
stmt.setString(4,hostname);
int i=stmt.executeUpdate();
if(i>0)
{
frame1.setAlwaysOnTop(false);
JOptionPane.showMessageDialog(null, "Sucessfully updated");
frame1.setVisible(false);
frame.setVisible(false);
}
}
}
catch(Exception my)
{
System.out.println(my);
}
}
protected static void studentframe()
{
frame1 = new JFrame("Student");
frame1.setUndecorated(true);
frame1.setAlwaysOnTop(true);
frame1.setDefaultCloseOperation(JFrame.DO_NOTHING_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setOpaque(true);
contentPane.setBackground(SystemColor.activeCaption);
contentPane.setLayout(null);
JTextField stname=new JTextField("");
stname.setBounds(560, 350,200, 25);
JTextField stuid = new JTextField("");
stuid.setBounds(560,380,150,25);
JLabel namel=new JLabel("Student Name");
JLabel idl=new JLabel("Student ID");
namel.setBounds(400, 350, 140, 25);
idl.setBounds(400, 380, 140, 25);
JButton submit=new JButton("Submit");
JButton back=new JButton("Back");
submit.setLayout(null);
back.setBounds(560,445 , 80, 25);
submit.setBounds(560,415 , 80, 25);
contentPane.add(namel);
contentPane.add(idl);
contentPane.add(stname);
contentPane.add(stuid);
contentPane.add(submit);
contentPane.add(back);
frame1.setSize(1500,700 );
frame1.setContentPane(contentPane);
frame1.setLocationRelativeTo(null);
frame1.setVisible(true);
frame.setVisible(false);
DocumentFilter filter = new UppercaseDocumentFilter();
AbstractDocument firstNameDoc = (AbstractDocument) stuid.getDocument();
firstNameDoc.setDocumentFilter(filter);
back.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
// display/center the jdialog when the button is pressed
frame1.setVisible(false);
frame.setVisible(true);
}
});
submit.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
try
{
Home.studentins(stname.getText(),stuid.getText());
}
catch (Exception e2)
{
}
}
});
}
protected static void studentins(String stuname,String id) throws IOException
{
InetAddress ip=InetAddress.getLocalHost();
String hostname=ip.getHostName();
String str=ip.toString();
stdid=id;
String ipaddress=str.substring(str.indexOf("/")+1);
if(stuname.equals("")||id.equals(""))
{
frame1.setAlwaysOnTop(false);
JOptionPane.showMessageDialog(null, "please fill all the fields");
frame1.setAlwaysOnTop(true);
}
else
{
try{
Class.forName("com.mysql.jdbc.Driver");
Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/userauth","root","");
PreparedStatement stmt=conn.prepareStatement("insert into students(stname,stid,hostname,ipaddress,date)values(?,?,?,?,NOW())");
stmt.setString(1, stuname);
stmt.setString(2, id);
stmt.setString(3,hostname);
stmt.setString(4,ipaddress);
int i=stmt.executeUpdate();
if(i>0)
{
frame1.setAlwaysOnTop(false);
JOptionPane.showMessageDialog(null, "Sucessfully updated");
frame1.setVisible(false);
frame.setVisible(false);
}
}
catch(Exception a)
{
System.out.println(a);
}
}
}
public static void main(String args[]) throws IOException, URISyntaxException
{
new Home();
Runtime.getRuntime().addShutdownHook(new Thread()
{
@Override
public void run()
{
try {
Class.forName("com.mysql.jdbc.Driver");
Connection conn=DriverManager.getConnection("jdbc:mysql://localhost:3306/userauth","root","");
if(!facname.equals(""))
{
PreparedStatement stmt=conn.prepareStatement("update faculty set status=? where facname=?");
stmt.setString(1, "loggedout");
stmt.setString(2,stdid);
}
else if(!stdid.equals(""))
{
PreparedStatement stmt=conn.prepareStatement("update students set status=? where stid=?");
stmt.setString(1, "loggedout");
stmt.setString(2,stdid);
}
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
}
class UppercaseDocumentFilter extends DocumentFilter {
@Override
public void insertString(DocumentFilter.FilterBypass fb, int offset, String text, AttributeSet attr) throws BadLocationException {
fb.insertString(offset, text.toUpperCase(), attr);
}
@Override
public void replace(DocumentFilter.FilterBypass fb, int offset, int length, String text, AttributeSet attrs) throws BadLocationException {
fb.replace(offset, length, text.toUpperCase(), attrs);
}
}
答案 0 :(得分：2)
您可以在
时注册要运行的Thread
当最后一个非守护程序线程退出或时，程序正常退出 当调用exit（等效，System.exit）方法时，或
虚拟机终止以响应用户中断， 例如键入^ C或系统范围的事件，例如用户注销或 系统关闭。
请参阅：Runtime.addShutdownHook(Thread)
以下链接中的示例：
Runtime.getRuntime().addShutdownHook(new Thread() {
public void run() { database.close(); }
});
关于它的一些FaQ here。