java是一种高级语言，也可以用来做小程序也可以做网页，可以说应用于生活中各个地方，那java怎么做一个登录页面?下面来我们就来给大家讲解一下java做一个登录页面的方法。
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 = 1 L;
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;
这就是java做一个简单登陆页面的过程，总之没有什么难度，不会的朋友多练习几遍就可以啦!最后大家如果想要了解更多java实例知识，敬请关注奇Q工具网。
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