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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