用javaSwing和mysql数据库做的一个登录页面

一：首先在eclipse中新建一个java工程

二：然后新建一个包，并且在包中新建两个类：一个事登录用的界面(Login)类，一个事连接数据库的（jdbcs）类我建立的是p4这个包

三：导入包mysql-connector-java-8.0.16.jar并且要添加到构建路径不添加到构建路径项目工程不会读出来的

(原先的驱动com.mysql.jdbc.Driver已经升级到了com.mysql.cj.jdbc.Driver)

maven项目可以加入

    mysql
    mysql-connector-java
    8.0.16

四：编写那个界面Login类

那个界面类的源代码如下：

 

import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.*;

/**
 * @author yh128
 * @version 1.0.0
 * @ClassName Login.java
 * @Description 登录类
 * @Param
 * @createTime 2019年06月11日 11:27:00
 */
public class Login extends JFrame implements ActionListener {
    private JPanel pan = new JPanel();
    private JLabel namelab = new JLabel("用户名");
    private JLabel passlab = new JLabel("密    码");
    private JTextField nametext = new JTextField();
    private JPasswordField passtext = new JPasswordField();


    public JButton denglu = new JButton("登录");
    public JButton zhuce = new JButton("注册");
    public JButton updatepass = new JButton("修改密码");
    public JButton deleteuser = new JButton("删除用户");


    public Login() {
        Font font = new Font("宋体", Font.BOLD, 12);
        super.setTitle("欢迎登录本系统");
        pan.setLayout(null);
        namelab.setBounds(20, 20, 60, 30);
        nametext.setBounds(90, 20, 140, 30);
        passlab.setBounds(20, 60, 60, 30);
        passtext.setBounds(90, 60, 140, 30);
        denglu.setBounds(30, 120, 90, 20);
        zhuce.setBounds(140, 120, 90, 20);
        updatepass.setBounds(30, 150, 90, 20);
        deleteuser.setBounds(140, 150, 90, 20);

        pan.add(namelab);
        pan.add(nametext);
        pan.add(passlab);
        pan.add(passtext);
        pan.add(denglu);
        pan.add(zhuce);
        pan.add(updatepass);
        pan.add(deleteuser);

        passtext.setFont(font);
        zhuce.setFont(font);
        updatepass.setFont(font);
        deleteuser.setFont(font);

        denglu.addActionListener(this);
        zhuce.addActionListener(this);
        updatepass.addActionListener(this);
        deleteuser.addActionListener(this);

        super.add(pan);
        super.setSize(300, 250);
        super.setVisible(true);
    }

    public static void main(String[] args) {

        new Login();
    }

    @Override
    public void actionPerformed(ActionEvent arg0) {
        if (arg0.getSource() == denglu) {
            denglu();
        } else if (arg0.getSource() == zhuce) {
            zhuce();
        } else if (arg0.getSource() == updatepass) {
            updatepass();
        } else if (arg0.getSource() == deleteuser) {
            deleteuser();
        }

    }

    //登录按钮的事件处理函数
    public void denglu() {
        Jdbcs d = new Jdbcs();
        String username = nametext.getText();
        String password = passtext.getText();
        if (d.compare(username, password)) {
            JOptionPane.showMessageDialog(null, "登录成功！");
            super.setVisible(false);
        }
    }

    //注册按钮触发后的事件处理函数
    public void zhuce() {
        Jdbcs d = new Jdbcs();
        String username = nametext.getText();
        String password = passtext.getText();
        d.insert(username, password);
    }

    //修改密码按钮触发后的事件处理函数
    public void updatepass() {
        pan.setEnabled(false);
        JFrame frame1 = new JFrame("密码修改");
        frame1.setSize(250, 200);
        JPanel updatepass = new JPanel();
        JLabel namelab1 = new JLabel("用户名");
        JLabel passlab1 = new JLabel("旧密码");
        JLabel newpasslab = new JLabel("新密码");
        JTextField nametext1 = new JTextField("" + nametext.getText());
        JPasswordField passtext1 = new JPasswordField();
        JPasswordField newpasstext = new JPasswordField();
        JButton ok = new JButton("修改");
        JButton resert = new JButton("重置");

        updatepass.setLayout(null);

        namelab1.setBounds(5, 5, 70, 20);
        nametext1.setBounds(80, 5, 120, 20);
        passlab1.setBounds(5, 30, 70, 20);
        passtext1.setBounds(80, 30, 120, 20);
        newpasslab.setBounds(5, 60, 70, 20);
        newpasstext.setBounds(80, 60, 120, 20);
        ok.setBounds(10, 110, 60, 20);
        resert.setBounds(90, 110, 60, 20);

        updatepass.add(namelab1);
        updatepass.add(nametext1);
        updatepass.add(passlab1);
        updatepass.add(passtext1);
        updatepass.add(newpasslab);
        updatepass.add(newpasstext);
        updatepass.add(ok);
        updatepass.add(resert);

        frame1.add(updatepass);
        frame1.setVisible(true);

        ok.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent arg0) {
                Jdbcs d = new Jdbcs();
                String username = nametext1.getText();
                String password1 = passtext1.getText();
                String newpassword = newpasstext.getText();
                if (d.update(username, password1, newpassword)) {
                    frame1.setVisible(false);
                }
            }
        });
        //重置文本框 里的内容
        resert.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent arg0) {

                nametext1.setText("");
                passtext1.setText("");
                newpasstext.setText("");
            }
        });
    }

    //删除用户按钮触发后的事件处理函数
    public void deleteuser() {
        String username = nametext.getText();
        String password = passtext.getText();
        Jdbcs s = new Jdbcs();
        s.delete(username, password);
    }

}

 

 

五：写连接数据库的代码以及用到的操作的源代码

jdbcs这个类的源代码如下：

 

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
 * @author yh128
 * @version 1.0.0
 * @ClassName Jdbcs.java
 * @Description 数据库连接类
 * @Param
 * @createTime 2019年06月11日 11:28:00
 */

import javax.swing.JOptionPane;

public class Jdbcs {
    Connection con = null;
    Statement statement = null;
    ResultSet res = null;
    String driver = "com.mysql.cj.jdbc.Driver";
    String url = "jdbc:mysql://localhost:3306/user?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai";
    String name = "root";
    String passwd = "123456";

    public Jdbcs() {
        try {
            Class.forName(driver).newInstance();
            con = DriverManager.getConnection(url, name, passwd);
            statement = con.createStatement();

        } 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();
        }
    }

    //对用户信息的修改实际上就是对密码的修改
    public boolean update(String username1, String password1, String newpassword) {
        boolean judge = false;
        boolean s = compare(username1, password1);
        if (s) {
            String sql = "update user set password=\"" + newpassword + "\"where username=\"" + username1 + "\"";
            try {
                int a = statement.executeUpdate(sql);
                if (a == 1) {
                    JOptionPane.showMessageDialog(null, "密码修改成功！");
                    judge = true;
                }
                con.close();
                statement.close();
            } catch (SQLException e) {
                JOptionPane.showMessageDialog(null, "用户不存在！");
                e.printStackTrace();
            }
        } else {
            JOptionPane.showMessageDialog(null, "修改失败");
        }
        return judge;
    }

    //删除用户信息
    public void delete(String username, String password) {
        if (compare(username, password)) {
            JOptionPane.showMessageDialog(null, "已经完成删除");
        } else {
            return;
        }
        String sql = "delete from user where username=\"" + username + "\"";
        try {
            int a = statement.executeUpdate(sql);
            con.close();
            statement.close();
        } catch (SQLException e) {
            JOptionPane.showMessageDialog(null, "不存在该用户！");
            e.printStackTrace();
        }

    }

    //用户注册功能的实现，添加数据
    public void insert(String username, String password) {
        if (username == null || username.trim().length() <= 0) {
            JOptionPane.showMessageDialog(null, "注册账号为空，请重新输入！");
            return;
        }
        String sql = "insert into user(username,password) values(\"" + username + "\",\"" + password + "\")";
        try {
            int a = statement.executeUpdate(sql);
            con.close();
            statement.close();
            if (a == 1) {
                JOptionPane.showMessageDialog(null, "注册成功！");
            }
        } catch (SQLException e) {
            JOptionPane.showMessageDialog(null, "对不起该用户名已经有了！");
            e.printStackTrace();
        }
    }

    //对比用户名和密码是不匹配
    public boolean compare(String username, String password) {
        boolean m = false;
        String sql = "select password from user where username=\"" + username + "\"";
        try {
            res = statement.executeQuery(sql);
            if (res.next()) {
                String pa = res.getString(1);
                System.out.println(pa + " " + password);
                if (pa.equals(password)) {
                    m = true;
                } else {
                    JOptionPane.showMessageDialog(null, "密码错误！");
                }
            } else {
                JOptionPane.showMessageDialog(null, "用户名不存在！");
            }
            res.close();
            con.close();
            statement.close();

        } catch (SQLException e) {
            e.printStackTrace();
        }
        return m;
    }

}

六：代码写完了 但是数据库还没有建立吧，那就建立数据库吧

先建立一个数据库

用到命令是

create database user;

然后新建一个表：

use user;

create table user(username varchar(20) primary key, password varchar(20));

现在表是空的，往表中添加几个数据：

insert into user(username,password) values("A",“123456”）,("B","asdfg");