conn.java

java + sqlserver2000编写的一个网上购书系统,实现了一些基本的功能,但对于初学者来说这个系统已经足以起到帮助作用

package ConnBean;
import java.io.*;
import java.sql.*;
import java.util.*;
public class conn
{
   Connection conn=null;
   Statement stmt=null;
   ResultSet rs=null;
  
 public conn()
  {
  	try
    {
       Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");}
       catch(java.lang.ClassNotFoundException e)
       {System.err.println(e.getMessage());}
    }
 
 public static void main(String args[])
 {
	 
 }
 public ResultSet executeQuery(String sql)
  {
  	try
      {
       conn=DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=book;user=sa;password=123");
       stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
       rs=stmt.executeQuery(sql);
      }catch(SQLException ex){System.err.println(ex.getMessage());}
       return rs;
  }
 
 public int executeUpdate(String sql)
  {int result=0;
   try
      {
       conn=DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;DatabaseName=book;user=sa;password=123");
       stmt=conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,ResultSet.CONCUR_READ_ONLY);
       result=stmt.executeUpdate(sql);
      }catch(SQLException ex){result=0;}
   return result;
  }
  
 public void close()
  {try
      {if(rs!=null)
        rs.close();
      }catch(Exception e){e.printStackTrace(System.err);}
   try
      {if(stmt!=null)
        stmt.close();
      }catch(Exception e){e.printStackTrace(System.err);}
   try
      {if(conn!=null)
        conn.close();
      }catch(Exception e){e.printStackTrace(System.err);}
  }
}