java连接mysql显示数据库

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DatabaseConnection {
    public static void main(String[] args) {
        // MySQL数据库连接信息
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String username = "root";
        String password = "password";

        try {
            // 加载MySQL JDBC驱动
            Class.forName("com.mysql.jdbc.Driver");

            // 建立数据库连接
            Connection connection = DriverManager.getConnection(url, username, password);

            // 连接成功后的操作
            // ...

            // 关闭数据库连接
            connection.close();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

import java.sql.*;

public class DatabaseConnection {
    public static void main(String[] args) {
        // MySQL数据库连接信息
        String url = "jdbc:mysql://localhost:3306/mydatabase";
        String username = "root";
        String password = "password";

        try {
            // 加载MySQL JDBC驱动
            Class.forName("com.mysql.jdbc.Driver");

            // 建立数据库连接
            Connection connection = DriverManager.getConnection(url, username, password);

            // 执行SQL查询
            Statement statement = connection.createStatement();
            String sql = "SELECT * FROM tablename";
            ResultSet resultSet = statement.executeQuery(sql);

            // 处理查询结果
            while (resultSet.next()) {
                // 获取数据并显示
                String columnName1 = resultSet.getString("column1");
                String columnName2 = resultSet.getString("column2");
                System.out.println(columnName1 + " " + columnName2);
            }

            // 关闭结果集、语句和连接
            resultSet.close();
            statement.close();
            connection.close();
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}