jsp连接数据库 - Java / Java EE

这是javaBean 

package comm;

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

public class BookSearch {
 private ResultSet rs;
 private ResultSetMetaData rsmd;
 private Connection conn=null;
public BookSearch()
{
  try{
  String driver="com.microsoft.sqlserver.jdbc.SQLServerDriver";
  String url="jdbc:sqlserver://127.0.0.1:1433;databaseName=master";
  String name="sa";
  String password="1";

 
  Class.forName(driver);
  conn=DriverManager.getConnection(url,name,password);
  Statement stat=conn.createStatement();
  rs=stat.executeQuery("select * from My_Book");
  rsmd=rs.getMetaData();
  }catch(Exception e){e.printStackTrace();}
  }
public ResultSet getRs()
{
return rs;
}
public ResultSetMetaData getRsmd()
{
return rsmd;
}
public void Print()
{
try{
System.out.println(rsmd.getColumnCount());
}catch(Exception e){e.printStackTrace();}
}
}
  


如果加个main()函数直接可用 打出rsmd.getColumnCount()的值

但是放