dblink.java

jsp做的购物网站

package jspD;
import java.sql.*;
import java.util.*;

public class DBLink{
	String url,user,password;
	private Connection conn; 
	private Statement stmt;
	private ResultSet rs=null;
	
	
	public ResultSet getRS(){
		return rs;
	}
	
	public DBLink() {
		url="jdbc:microsoft:sqlserver://localhost:1499;DatabaseName=jspDB";
		user="sa";
		password="sa";
		try{
			Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver").newInstance();
		}catch(Exception e){		//it can't use SQLException!!
			e.printStackTrace();
		}
	}
	//It can return the ResultSet
	public ResultSet executeQuery(String sql){
		rs=null;
		try{
			conn=DriverManager.getConnection(url,user,password);
			stmt=conn.createStatement();
			rs=stmt.executeQuery(sql);
		}catch(Exception e){
			System.err.println("!!sqldata.executeQuery:"+e.getMessage());
		}
		return rs;			
	}
	//It can insert,delete,update
	public boolean executeUpdate(String sql){
		
		try{
			conn=DriverManager.getConnection(url,user,password);
			stmt=conn.createStatement();
			stmt.executeUpdate(sql);	//it return a int 
		}catch(Exception e){
			System.err.println("!!sqldata.executeInsert:"+e.getMessage());
			return false;
		}
		return true;
	}
	
	public boolean hasUser(){
	/*	try{
			if(rs.next())
				return true;			
		}catch(Exception e){
			e.printStackTrace();
		}*/
		return false;
	}
	public void disConn(){
		try{
			rs.close();
			stmt.close();
			conn.close();
		}catch(Exception e){
			e.printStackTrace();
		}
	}
	
}