一个购物的数据库bean

package javabean;

import java.io.UnsupportedEncodingException;
import java.sql.*;
import java.util.*;
import javabean.Goods;
import javabean.Orders;

public class ConnectionDB {


    Connection con=null;
    Statement st=null;
    Orders ord=null;
    PreparedStatement pst = null;
    public ConnectionDB(){}

    public Vector listGoods(int page){//显示出数据库中所有商品
        jdbcConnection();
        String sql="select * from goods limit "+page+",5";
        Vector v=new Vector();
        try {
            ResultSet rs=st.executeQuery(sql);
            Goods goods=null;
            
            while(rs.next()){
                goods=new Goods();
                goods.setId(rs.getInt("id"));            
                goods.setName(rs.getString("name"));
                goods.setType(rs.getString("type"));
                goods.setPrice(rs.getDouble("price"));
                v.addElement(goods);
            }
            return v;
            
        } catch (SQLException e) {
            e.printStackTrace();
            return v;
        } 
    }
    
    public String chString(String str){//解决显示在页面上的中文乱码
        try{
            if(str.equals("")){
                str="";
            }
            else str=new String(str.getBytes("ISO8859-1"),"GB2312");
        }catch(Exception e){
            e.printStackTrace();
            e.getMessage();
        }
        return str;
    }
    
    public Vector selectRecord(String str){//查找商品
        jdbcConnection();
        Vector v=new Vector();
        String sql="select id,name,type,price from goods where name like '%"+str+"%'";
        try {
            ResultSet rs=st.executeQuery(sql);
            Goods goods=null;
            while(rs.next()){
                goods=new Goods();
                goods.setId(rs.getInt("id"));
                goods.setName(rs.getString("name"));
                goods.setType(rs.getString("type"));
                goods.setPrice(rs.getDouble("price"));
                v.addElement(goods);
            }
            return v;            
        } catch (SQLException e) {
            e.printStackTrace();
            return v;
        } 
        
        
    }
    
    public boolean isExist(String name,String password) //用户登陆
    {        
        jdbcConnection();
        ResultSet rs=null;
        try {
            pst=con.prepareStatement("select * from register where name=? and password=? ");
            pst.setString(1,name);
            pst.setString(2,password);

            rs=pst.executeQuery();            
            if(rs.next()){
                return true;
            }
           } catch (Exception e) {
               System.out.println("您所输入的用户名或密码不存在");
            System.out.println(e.getMessage());
        }
        return false;
    }
    
    public boolean zhuCu(String name,String password,String sex,String degree)//用户注册
    {
        jdbcConnection();
        try {
            String sq="select name from register where name='"+name+"'";
            ResultSet rs=st.executeQuery(sq);
            if(rs.next()){
                System.out.println("用户名已存在！");
                return false;
            }
                
            String sql="insert into register(name,password,sex,degree) values(?,?,?,?)";
            pst=con.prepareStatement(sql);
            pst.setString(1,name);
            pst.setString(2,password);
            pst.setString(3,sex);
            pst.setString(4,degree);
            pst.executeUpdate(); 
            
            pst=con.prepareStatement("insert into login(name,password) values(?,?)");
            pst.setString(1,name);
            pst.setString(2,password);
            pst.executeUpdate();
            System.out.println("插入成功");
            return true;
        } catch (Exception e) {
            System.out.println("您所输入的类型与数据库不符");
            System.out.println(e.getMessage());
        }
        return false;
    }
    
    public void jdbcConnection(){//连接数据库
        try {
            Class.forName("org.gjt.mm.mysql.Driver");
            con=DriverManager.getConnection("jdbc:mysql://127.0.0.1:3309/shopping","root","root");
            st=con.createStatement();
            System.out.println("数据库已连接");
        } catch (Exception e) {
            System.out.println(e.getMessage());
            e.printStackTrace();
        }
    }
    
    public static void main(String[] args){
        ConnectionDB con=new ConnectionDB();
        con.zhuCu("方法","admin","fmale","dgree");
    }


}