在Java中格式化SQL查询的输出

import java.sql.*;

public class SQLQueryFormatter {
    public static void main(String[] args) {
        try {
            // 连接数据库
            Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/mydatabase", "username", "password");
            
            // 执行SQL查询
            Statement stmt = conn.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT * FROM mytable");
            
            // 获取结果集的元数据
            ResultSetMetaData rsmd = rs.getMetaData();
            int columnCount = rsmd.getColumnCount();
            
            // 输出列名
            for (int i = 1; i <= columnCount; i++) {
                String columnName = rsmd.getColumnName(i);
                System.out.printf("%-20s", columnName);
            }
            System.out.println();
            
            // 输出每行数据
            while (rs.next()) {
                for (int i = 1; i <= columnCount; i++) {
                    String columnValue = rs.getString(i);
                    System.out.printf("%-20s", columnValue);
                }
                System.out.println();
            }
            
            // 关闭连接
            rs.close();
            stmt.close();
            conn.close();
        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}