mysql存入数据库乱码

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

public class MySQLExample {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/your_database_name?useUnicode=yes&characterEncoding=UTF-8";
        String user = "your_username";
        String password = "your_password";

        try (Connection conn = DriverManager.getConnection(url, user, password)) {
            String sql = "INSERT INTO your_table_name (column_name) VALUES (?)";
            try (PreparedStatement pstmt = conn.prepareStatement(sql)) {
                pstmt.setString(1, "你好，世界！");
                pstmt.executeUpdate();
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}