(JDBC)java连接数据库，试手登陆注册系统

查了查网上的资料，发现导入jdbc的jar包十分繁琐，我就想到了maven。

maven是个十分方便的包管理平台，既然导入jar如此麻烦，使用它会便捷很多。

创建个带maven的web项目。
打开里面的pom.xml进行导入包。

      net.jahhan
      jdbc-api
      1.0.0-RELEASE
    

这个是jdbc的jar包，直接写在maven中。

然后刷新一下maven，jar就会自动下载安装。

先创建mysql数据库(这里已经提前创建好了)

`后面是注册和登录模块的

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;

public class register {//注册
    static String username;
    static String passwords;
    public static String getUsername() {
        return username;
    }

    public static String getPassword() {
        return passwords;
    }

    public register(){
        Jframe jf=new Jframe("注册界面");
        final JPanel jPanel=new JPanel();
        jf.setBounds(300,300,300,120);
        jPanel.setBounds(300,300,300,300);
        jPanel.setBackground(Color.darkGray);
        final JTextField jt1=new JTextField("账号",20);
        final JTextField jt2=new JTextField("密码",20);
        JButton jButton=new JButton("注册");
        jPanel.add(jt1,BorderLayout.CENTER);
        jPanel.add(jt2,BorderLayout.CENTER);
        jPanel.add(jButton);
        jf.add(jPanel);
        jf.setVisible(true);
        jf.setDefaultCloseOperation(jf.EXIT_ON_CLOSE);

        jButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String _username=jt1.getText();
                String _password=jt2.getText();



                try {
                    Class.forName("com.mysql.cj.jdbc.Driver");
                    PreparedStatement ps=null;
                    PreparedStatement ps1=null;
                    String url="jdbc:mysql://localhost:3306/SQLSystem?useSSL=false&serverTimezone=UTC";
                    String user="root";
                    String password="ccx425273580";
                    Connection conn = DriverManager.getConnection(url,user,password);
                    String sql="insert into SQLSystem(user,password) values(?,?)";
                    String sql1="select user from SQLSystem";
                    ps=conn.prepareStatement(sql);
                    ps1= conn.prepareStatement(sql1);
                    ps.setString(1,_username);
                    ps.setString(2,_password);
                    ResultSet rs= ps1.executeQuery();
                    while(rs.next()){
                        String s=rs.getString("user");
                        if (s.equals(_username)){
                            JOptionPane.show/confirm/iDialog(jPanel,"账号已经存在","提示",0);
                        }else{
                            ps.executeUpdate();
                            JOptionPane.show/confirm/iDialog(jPanel,"注册成功","提示",0);
                        }
                    }

                    ps.close();
                    conn.close();

                } catch (ClassNotFoundException | SQLException ex) {
                    JOptionPane.show/confirm/iDialog(jPanel,"账号已经存在","提示",0);
                }
            }
        });
    }

    public static void main(String[] args) {
        register register=new register();
    }


}

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.sql.*;

public class sign {//登陆
    public sign(){
        Jframe jf=new Jframe("登陆界面");
        final JPanel jPanel=new JPanel();
        jf.setBounds(300,300,300,120);
        jPanel.setBounds(300,300,300,300);
        jPanel.setBackground(Color.darkGray);
        final JTextField jt1=new JTextField("账号",20);
        final JTextField jt2=new JTextField("密码",20);
        JButton jButton=new JButton("登陆");
        jPanel.add(jt1,BorderLayout.CENTER);
        jPanel.add(jt2,BorderLayout.CENTER);
        jPanel.add(jButton);
        jf.add(jPanel);
        jf.setVisible(true);
        jf.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE);

        jButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {

                String _user=jt1.getText();
                String _password=jt2.getText();
                try {
                    Class.forName("com.mysql.cj.jdbc.Driver");
                    String url="jdbc:mysql://localhost:3306/SQLSystem?useSSL=false&serverTimezone=UTC";
                    String user="root";
                    String password="ccx425273580";
                    Connection conn = DriverManager.getConnection(url,user,password);
                    String sql="select password from SQLSystem where user=?";
                    String sql1="select user from SQLSystem";
                    PreparedStatement ps=conn.prepareStatement(sql);
                    PreparedStatement ps1=conn.prepareStatement(sql1);
                    ps.setString(1,_user);
                    ResultSet rs=ps.executeQuery();
                    ResultSet rs1= ps1.executeQuery();
                    int count=0;
                    while(rs1.next()){
                        String user1=rs1.getString("user");
                        if (user1.equals(user)){
                            JOptionPane.show/confirm/iDialog(jPanel,"登陆成功","提示",0);

                        }else{
                            count=1;


                        }

                    }
                    if (count == 1) {
                        JOptionPane.show/confirm/iDialog(jPanel,"账号或密码错误","提示",0);
                    }

                    while(rs.next()){
                        String password1=rs.getString("password");
                        if (password1.equals(_password)){
                            JOptionPane.show/confirm/iDialog(jPanel,"登陆成功","提示",0);
                        }else{
                            JOptionPane.show/confirm/iDialog(jPanel,"账号或密码错误","提示",0);
                        }
                    }
                } catch (ClassNotFoundException | SQLException ex) {
                    ex.printStackTrace();
                }

            }
        });
    }

    public static void main(String[] args) {
        sign sign=new sign();
    }
}

下面是测试。



第一个版本可能还有些许bug，大家指正出来，修订一下。