Java简单登陆界面实现

利用Java连接MySQL做登陆界面
1、首先需要建立一个类，在这里，我命名为newLogin
newLogin类的代码如下

package p4;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPasswordField;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
public class newLogin extends JFrame implements ActionListener{
private static final long serialVersionUID = 1L;
private Connection con = null;
private Statement statement = null;
private ResultSet res = null;
private ButtonGroup buttongroup = new ButtonGroup();
private MyPanel jp = new MyPanel();
private JLabel ul = new JLabel("用户名：");
private JLabel pl = new JLabel("密    码：");
private JLabel ts = new JLabel("");
private JTextField uname = new JTextField();
private JPasswordField pword = new JPasswordField();
private JRadioButton[] butArray = {
new JRadioButton("学生",true),
new JRadioButton("教师")
};
private JButton login = new JButton("登陆");
private JButton reset = new JButton("重置");
public newLogin() {
addListener();
initialFrame();
}
private void initialFrame() {
Font font = new Font("宋体",Font.BOLD,12);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setTitle("登陆");
jp.setLayout(null);
ul.setBounds(100, 30, 60, 30);
jp.add(ul);
uname.setBounds(170, 30, 140, 30);
jp.add(uname);
pl.setBounds(100, 80, 60, 30);
pword.setBounds(170, 80, 140, 30);
jp.add(pl);
jp.add(pword);
ts.setBounds(100, 160, 200, 50);
jp.add(ts);
ts.setFont(font);
login.setBounds(100, 220, 70, 30);
jp.add(login);
login.setFont(font);
reset.setBounds(220, 220, 70, 30);
jp.add(reset);
reset.setFont(font);
add(jp);
setResizable(false);
buttongroup.add(butArray[0]);
buttongroup.add(butArray[1]);
butArray[0].setBounds(120, 130, 100, 50);
jp.add(butArray[0]);
butArray[1].setBounds(220, 130, 100, 50);
jp.add(butArray[1]);
butArray[0].setContentAreaFilled(false);
butArray[1].setContentAreaFilled(false);
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
int centerX = screenSize.width/2;
int centerY = screenSize.height/2;
int w = 427;
int h = 331;
setBounds(centerX-w/2, centerY-h/2, w, h);
setVisible(true);
uname.requestFocus(true);
getContentPane().add(jp);
jp.getRootPane().setDefaultButton(login);
}
private void addListener() {
this.login.addActionListener(this);
this.uname.addActionListener(this);
this.pword.addActionListener(this);
}
@Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == uname) {
pword.requestFocus();
}
if(e.getSource() == pword) {
butArray[0].requestFocus();
}
if(e.getSource() == butArray[0]||e.getSource() == butArray[1]||e.getSource() == login) {
//			this.ts.setText("正在为您努力加载，请稍等......");

int type = this.butArray[0].isSelected()?0:1;
String username = this.uname.getText().trim();
char[] p = this.pword.getPassword();
String password = String.valueOf(p).trim();
if(username.equals("")) {
JOptionPane.showMessageDialog(this, "请输入用户名！","错误",JOptionPane.ERROR_MESSAGE);
ts.setText("");
return ;
}
if(password.equals("")) {
JOptionPane.showMessageDialog(this, "请输入密码！","错误",JOptionPane.ERROR_MESSAGE);
ts.setText("");
return ;
}
try {
con = new connection().getConnection();  //调用自己写的一个数据库连接类
statement = con.createStatement();
if(type == 0) {
String sql = "select * from stuuser where "+
"username_stu='"+username+"'and password_stu='"+password+"'";
res = statement.executeQuery(sql);
if(res.next()) {
JOptionPane.showMessageDialog(this, "登录成功！","提示",JOptionPane.INFORMATION_MESSAGE);
this.dispose();
}
else {
JOptionPane.showMessageDialog(this, "用户名或密码错误！","错误",JOptionPane.ERROR_MESSAGE);
ts.setText("");
uname.setText("");
pword.setText("");
}
//关闭数据库连接
if(res != null) {
res.close();
}
if(statement != null) {
statement.close();
}
if(con != null) {
con.close();
}
}
else {
String sql = "select * from teauser where "+
"username_tea='"+username+"'and password_tea='"+password+"'";
res = statement.executeQuery(sql);
if(res.next()) {
String spec_name = res.getString(1);
JOptionPane.showMessageDialog(this, "登录成功！","提示",JOptionPane.INFORMATION_MESSAGE);
this.dispose();
}
else {
JOptionPane.showMessageDialog(this, "用户名或密码错误！","错误",JOptionPane.ERROR_MESSAGE);
ts.setText("");
uname.setText("");
pword.setText("");
}
//关闭数据库连接
if(res != null) {
res.close();
}
if(statement != null) {
statement.close();
}
if(con != null) {
con.close();
}
}
}catch(SQLException ea) {
ea.printStackTrace();
}
}
else if(e.getSource() == reset) {
uname.setText("");
pword.setText("");
}
}
}

2、编写数据库连接类，在这里命名为connection,然后在类里写一个获取连接的放回，并返回一个连接。
connection类的代码如下：

package p4;

import java.sql.Connection;
import java.sql.DriverManager;
//import java.sql.ResultSet;
import java.sql.SQLException;
//import java.sql.Statement;

public class connection {
private Connection con = null;
//	private Statement statement = null;
//	private ResultSet res = null;
String driver = "com.mysql.cj.jdbc.Driver";
String url  = "jdbc:mysql://localhost:3306/Stu_manager?serverTimezone=Asia/Shanghai";
String name = "root";
String passwd = "123456";
public connection() {

}
public Connection getConnection() {
try{
Class.forName(driver).newInstance();
con = DriverManager.getConnection(url,name,passwd);
}catch(ClassNotFoundException e){
System.out.println("对不起，找不到这个Driver");
e.printStackTrace();
}catch(SQLException e){

e.printStackTrace();
}catch(Exception e){
e.printStackTrace();
}
return con;
}
}

3、在MySQL数据库中需建立两个用户表，分别用来存储不同用户的登陆账号和密码，这里学生用户表为stuuser,教师用户表为teauser,建表的SQL语句如下:
stuuser表：

create table stuuser(
username_stu varchar(20) primary key,
password_stu char(20) not null,
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

teauser表：

create table teauser(
username_tea varchar(20) primary key,
password_tea char(20) not null,
)ENGINE=InnoDB DEFAULT CHARSET=utf8;

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