package com.zuoye;import java.sql.*;import java.util.*;public class Test {public static String uid;public static void main(String[] args)throws Exception{Scanner sc = new Scanner(System.in);System.out.println("用户名：");uid =sc.nextLine();System.out.println("密码：");String pwd = sc.nextLine();Class.forName("com.mysql.jdbc.Driver");Connection conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/mydb?characterEconding=GBK","root","");String sql ="select * from login where UserName=? and Password=?";PreparedStatement p = conn.prepareStatement(sql);p.setString(1, uid);p.setString(2, pwd);ResultSet rs = p.executeQuery();boolean ok = rs.next();if(ok){System.out.println("欢迎您："+rs.getString(2));xuanxiang();}else{System.out.println("用户名或密码有误");}main(args);conn.close();}public static void xuanxiang() throws Exception{Scanner sc = new Scanner(System.in);System.out.println("*******选项*******");System.out.println("1.显示所有商品");System.out.println("2.添加商品");System.out.println("3.购买商品");System.out.println("4.退出");String a = sc.nextLine();if(a.equals("1")){liebiao();xuanxiang();}else if(a.equals("2")){tianjia();xuanxiang();}else if(a.equals("3")){goumai();xuanxiang();}else{return;}}public static void liebiao() throws Exception{Class.forName("com.mysql.jdbc.Driver");Connection conn1 = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/mydb?characterEncoding=GBK","root","");String sql1 = "select * from fruit";Statement state1 = conn1.createStatement();ResultSet rs1 = state1.executeQuery(sql1);while(rs1.next()){System.out.print(rs1.getString(1)+"\t");System.out.print(rs1.getString(2)+"\t");System.out.print(rs1.getString(3)+"\t");System.out.print(rs1.getString(4)+"\t");System.out.print(rs1.getString(5)+"\t");System.out.print(rs1.getString(6)+"\n");}conn1.close();}public static void tianjia() throws Exception{Scanner sc =new Scanner(System.in);System.out.println("请输入编号：");String bh =sc.nextLine();System.out.println("请输入品种：");String pz =sc.nextLine();System.out.println("请输入价格：");double jg =Double.parseDouble(sc.nextLine());System.out.println("请输入产地：");String cd =sc.nextLine();System.out.println("请输入数量：");int sl=Integer.parseInt(sc.nextLine());System.out.println("请输入图片地址：");String dz =sc.nextLine();Class.forName("com.mysql.jdbc.Driver");Connection conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/mydb?characterEconding=GBK","root","");String sql ="insert into fruit values(?,?,?,?,?,?)";PreparedStatement p = conn.prepareStatement(sql);p.setString(1, bh);p.setString(2, pz);p.setDouble(3, jg);p.setString(4, cd);p.setInt(5, sl);p.setString(6, dz);p.executeUpdate();conn.close();}public static void goumai() throws Exception{Class.forName("com.mysql.jdbc.Driver");Connection conn = DriverManager.getConnection("jdbc:mysql://127.0.0.1:3306/mydb?characterEncoding=GBK","root","");Scanner sc = new Scanner(System.in);System.out.println("购买什么水果");String pz = sc.nextLine();System.out.println("买多少");int gs = Integer.parseInt(sc.nextLine());String sql1 ="select * from fruit where Name=?";PreparedStatement p1 = conn.prepareStatement(sql1);p1.setString(1, pz);ResultSet rs2 = p1.executeQuery();double s = 0;while(rs2.next()){s =(rs2.getDouble(3)*gs);System.out.println(s);}String sql2="update fruit set Numbers = Numbers-? where Name =?";PreparedStatement p2 = conn.prepareStatement(sql2);p2.setInt(1, gs);p2.setString(2, pz);p2.executeUpdate();String sql3="update login set Account = Account-? where UserName =?";PreparedStatement p3 = conn.prepareStatement(sql3);p3.setDouble(1, s);p3.setString(2, uid);p3.executeUpdate();conn.close();}
}

用户名：
lisi
密码：
666666
欢迎您：李四
*******选项*******
1.显示所有商品
2.添加商品
3.购买商品
4.退出
1
k001    苹果    2.40    烟台    87    image/0.gif
k002    菠萝    1.40    广东    90    image/1.gif
k003    桔子    2.40    福州    90    image/2.gif
k004    葡萄    2.40    新缰    90    image/3.gif
k005    樱桃    2.40    青岛    90    image/4.gif
k006    桃子    2.40    花果山    90    image/5.gif
k007    香蕉    2.40    济南    90    image/6.gif
*******选项*******
1.显示所有商品
2.添加商品
3.购买商品
4.退出