mysql数据库端口代码

import pymysql

# 连接到MySQL数据库
connection = pymysql.connect(host='localhost', port=3306, user='username', password='password', database='dbname')

# 执行SQL查询
cursor = connection.cursor()
cursor.execute("SELECT * FROM table_name")
results = cursor.fetchall()

# 关闭连接
cursor.close()
connection.close()

import java.sql.*;

public class Main {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/dbname";
        String user = "username";
        String password = "password";
        
        try {
            // 加载MySQL JDBC驱动程序
            Class.forName("com.mysql.jdbc.Driver");
            
            // 建立连接
            Connection connection = DriverManager.getConnection(url, user, password);
            
            // 执行SQL查询
            Statement statement = connection.createStatement();
            ResultSet resultSet = statement.executeQuery("SELECT * FROM table_name");
            
            // 处理结果集
            while (resultSet.next()) {
                // 获取数据
                int id = resultSet.getInt("id");
                String name = resultSet.getString("name");
                // 其他字段...
                
                // 处理数据...
            }
            
            // 关闭连接
            resultSet.close();
            statement.close();
            connection.close();
        } catch (ClassNotFoundException | SQLException e) {
            e.printStackTrace();
        }
    }
}

const mysql = require('mysql2');

// 创建连接池
const pool = mysql.createPool({
    host: 'localhost',
    port: 3306,
    user: 'username',
    password: 'password',
    database: 'dbname'
});

// 从连接池中获取连接
pool.getConnection((err, connection) => {
    if (err) {
        console.error(err);
        return;
    }
    
    // 执行SQL查询
    connection.query('SELECT * FROM table_name', (error, results, fields) => {
        // 处理查询结果
        if (error) {
            console.error(error);
        } else {
            // 处理数据...
        }
        
        // 释放连接
        connection.release();
    });
});

// 关闭连接池
pool.end();