//【例11.2】  連接指定數據庫并獲得數據庫屬性信息。
//  數據庫操作類

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

public class DataBaseOperation
{
    private Connection connection;                         //數據庫連接對象 

    public DataBaseOperation(String driver,String url, String user, String password)
        throws ClassNotFoundException,SQLException
                     //構造方法，連接指定數據庫。4個參數分別指定JDBC驅動程序、數據庫URL、用戶名和密碼
    {
        this.connection = null;
        Class.forName(driver);                             //指定JDBC驅動程序
        this.connection = DriverManager.getConnection(url,user,password); //連接指定數據庫
    }

    public DataBaseOperation(String driver, String url) throws ClassNotFoundException,SQLException
    {
        this.connection = null;
        Class.forName(driver);
        this.connection = DriverManager.getConnection(url);
    }

    public void finalize() throws SQLException             //析構方法，關閉數據庫連接
    {
        this.connection.close();
    }

    public String getDBAbout() throws SQLException         //獲得所連接數據庫的屬性信息，返回字符串
    {
        String message = "";
        DatabaseMetaData dbmd = this.connection.getMetaData();
        message = "JDBC驅動程序：" + dbmd.getDriverName() +" "+ dbmd.getDriverVersion() + "\r\n" +
                  "JDBC URL：" + dbmd.getURL() + "\r\n" +
                  "數據庫：" + dbmd.getDatabaseProductName() + "\r\n" +
                  "數據庫版本：" + dbmd.getDatabaseProductVersion() + "\r\n"+
                  "用戶名：" + dbmd.getUserName() + "\r\n";
        return message;
    }
}