web连mysql数据库代码

import mysql.connector

# 建立数据库连接
mydb = mysql.connector.connect(
  host="数据库主机地址",
  user="用户名",
  password="密码",
  database="数据库名称"
)

# 创建数据库游标
cursor = mydb.cursor()

# 执行SQL查询
cursor.execute("SELECT * FROM 表名")

# 获取查询结果
result = cursor.fetchall()

# 遍历结果
for row in result:
  print(row)

# 关闭游标和数据库连接
cursor.close()
mydb.close()

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

public class Main {
  public static void main(String[] args) {
    Connection connection = null;
    Statement statement = null;
    ResultSet resultSet = null;

    try {
      // 加载数据库驱动
      Class.forName("com.mysql.cj.jdbc.Driver");

      // 建立数据库连接
      connection = DriverManager.getConnection(
        "jdbc:mysql://数据库主机地址/数据库名称?user=用户名&password=密码&serverTimezone=UTC"
      );

      // 创建执行SQL语句的对象
      statement = connection.createStatement();

      // 执行SQL查询
      resultSet = statement.executeQuery("SELECT * FROM 表名");

      // 处理查询结果
      while (resultSet.next()) {
        // 获取每行数据的列值
        String column1 = resultSet.getString("列名1");
        String column2 = resultSet.getString("列名2");
        // ...

        System.out.println(column1 + " - " + column2);
      }
    } catch (ClassNotFoundException | SQLException e) {
      e.printStackTrace();
    } finally {
      // 关闭结果集、声明和连接
      try {
        if (resultSet != null) {
          resultSet.close();
        }
        if (statement != null) {
          statement.close();
        }
        if (connection != null) {
          connection.close();
        }
      } catch (SQLException e) {
        e.printStackTrace();
      }
    }
  }
}

const mysql = require('mysql');

// 创建数据库连接
const connection = mysql.createConnection({
  host: '数据库主机地址',
  user: '用户名',
  password: '密码',
  database: '数据库名称'
});

// 连接数据库
connection.connect();

// 执行SQL查询
connection.query('SELECT * FROM 表名', (error, results, fields) => {
  if (error) {
    console.error(error);
  } else {
    results.forEach((row) => {
      console.log(row);
    });
  }
});

// 关闭数据库连接
connection.end();