mysql数据库java代码

import java.sql.*;

public class MySQLExample {
    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 = "123456";

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

            // 建立数据库连接
            Connection conn = DriverManager.getConnection(url, username, password);
            System.out.println("成功连接到MySQL数据库");

            // 执行SQL查询
            Statement stmt = conn.createStatement();
            String sql = "SELECT * FROM users";
            ResultSet rs = stmt.executeQuery(sql);

            // 处理查询结果
            while (rs.next()) {
                int id = rs.getInt("id");
                String name = rs.getString("name");
                System.out.println("ID: " + id + ", Name: " + name);
            }

            // 关闭数据库连接
            rs.close();
            stmt.close();
            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import java.sql.*;

public class MySQLExample {
    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 = "123456";

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

            // 建立数据库连接
            Connection conn = DriverManager.getConnection(url, username, password);
            System.out.println("成功连接到MySQL数据库");

            // 插入数据
            String sql = "INSERT INTO users (name, age) VALUES (?, ?)";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setString(1, "John");
            pstmt.setInt(2, 25);
            int rows = pstmt.executeUpdate();
            System.out.println(rows + "行数据已插入");

            // 关闭数据库连接
            pstmt.close();
            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import java.sql.*;

public class MySQLExample {
    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 = "123456";

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

            // 建立数据库连接
            Connection conn = DriverManager.getConnection(url, username, password);
            System.out.println("成功连接到MySQL数据库");

            // 更新数据
            String sql = "UPDATE users SET age = ? WHERE name = ?";
            PreparedStatement pstmt = conn.prepareStatement(sql);
            pstmt.setInt(1, 30);
            pstmt.setString(2, "John");
            int rows = pstmt.executeUpdate();
            System.out.println(rows + "行数据已更新");

            // 关闭数据库连接
            pstmt.close();
            conn.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}