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java水果超市登陆代码 java水果系统

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求大神指点，这是我用java写的超市管理系统，登录就出现这这都是小问题 。从LoginServletjava水果超市登陆代码的doPost方法查找下去!我猜啊，可能是java水果超市登陆代码你没处理null这种情况才出现java水果超市登陆代码的错误java水果超市登陆代码！比如一个对象为null就不应该拿来再用
了 ， 用之前呢先判断下java水果超市登陆代码！具体错因你可以自己查下是什么，可能没连接到数据库或找不到对应的数据等等返回了个null值，而此时你没做判断又用了它而造成的！重启下服务器看看 。
亲有java语言写的超市管理系统课程设计和源代码吗，能给我吗package untitled5;
import java.io.*;
import java.net.*;
import java.sql.*;
import java.lang.*;
import javax.sql.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import com.borland.jbcl.layout.*;
public class delbook extends JFrame {
JPanel contentPane;
XYLayout xYLayout1 = new XYLayout();
JLabel jLabel1 = new JLabel();
JLabel jLabel2 = new JLabel();
JLabel jLabel3 = new JLabel();
JTextField jTextField1 = new JTextField();
JLabel jLabel4 = new JLabel();
JTextField jTextField2 = new JTextField();
JLabel jLabel5 = new JLabel();
JTextField jTextField3 = new JTextField();
JLabel jLabel6 = new JLabel();
JTextField jTextField4 = new JTextField();
JButton jButton1 = new JButton();
//Construct the frame
public delbook() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
}
}
//Component initialization
private void jbInit() throws Exception {
contentPane = (JPanel) this.getContentPane();
jLabel1.setFont(new java.awt.Font("SansSerif", 0, 25));
jLabel1.setForeground(Color.red);
jLabel1.setText("超市管理系统");
contentPane.setLayout(xYLayout1);
this.setSize(new Dimension(500,400));
this.setTitle("超市管理系统");
jLabel2.setFont(new java.awt.Font("SansSerif", 0, 30));
jLabel2.setText("业务单位信息");
jLabel3.setFont(new java.awt.Font("SansSerif", 0, 25));
jLabel3.setText("产品编号");
jTextField1.setText("");
jLabel4.setFont(new java.awt.Font("SansSerif", 0, 25));
jLabel4.setText("公司名称");
jTextField2.setText("");
jLabel5.setFont(new java.awt.Font("SansSerif", 0, 25));
jLabel5.setText("订单号码");
jTextField3.setText("");
jLabel6.setFont(new java.awt.Font("SansSerif", 0, 25));
jLabel6.setText("电 话");
jTextField4.setText("");
jButton1.setFont(new java.awt.Font("SansSerif", 0, 25));
jButton1.setText("提交");
jButton1.addActionListener(new delbook_jButton1_actionAdapter(this));
contentPane.add(jLabel1, new XYConstraints(179, 1, 153, 32));
contentPane.add(jLabel2, new XYConstraints(162, 33, -1, -1));
contentPane.add(jLabel3, new XYConstraints(83, 89, -1, -1));
contentPane.add(jTextField1, new XYConstraints(189, 88, 141, 36));
contentPane.add(jTextField2, new XYConstraints(189, 149, 142, 36));
contentPane.add(jLabel4, new XYConstraints(84, 148, -1, -1));
contentPane.add(jTextField3, new XYConstraints(188, 206, 143, 33));
contentPane.add(jLabel5, new XYConstraints(84, 204, -1, -1));
contentPane.add(jLabel6, new XYConstraints(84, 253, -1, -1));
contentPane.add(jTextField4, new XYConstraints(189, 260, 143, 36));
contentPane.add(jButton1, new XYConstraints(197, 318, -1, -1));
}
//Overridden so we can exit when window is closed
protected void processWindowEvent(WindowEvent e) {
super.processWindowEvent(e);
if (e.getID() == WindowEvent.WINDOW_CLOSING) {
System.exit(0);
}
}
void update() {
try {
//定义显示java水果超市登陆代码的字符串
String str1;
String str2;
String str3;
String str4;
str1 = jTextField1.getText();
str2 = jTextField2.getText();
str3 = jTextField3.getText();
str4 = jTextField4.getText();
//装载jdbc驱动程序
String driverName = "oracle.jdbc.OracleDriver";
Driver driver = (Driver) Class.forName(driverName).newInstance();
//连接数据库
Connection con = DriverManager.getConnection(
"jdbc:oracle:thin:@thsspc0791:1521:liuyong", "hr", "tongfang");
PreparedStatement pstmt = con.prepareStatement(
" insert Customer1('goodID','Name','PID','tel')values(?,?,?,?)");
pstmt.setString(1, str1);
pstmt.setString(2, str2);
pstmt.setString(1, str3);
pstmt.setString(4, str4);
ResultSet res = pstmt.executeQuery();
pstmt.close();
con.close();
}catch (InstantiationException e) {
System.out.println(e.getMessage());
}catch (IllegalAccessException e) {
System.out.println(e.getMessage());
}catch (ClassNotFoundException e) {
System.out.println(e.getMessage());
}catch (SQLException edd) {
edd.printStackTrace() ;
System.out.println(edd.getMessage());
}
}
void jButton1_actionPerformed(ActionEvent e) {
update();
}
}
class delbook_jButton1_actionAdapter implements java.awt.event.ActionListener {
delbook adaptee;
delbook_jButton1_actionAdapter(delbook adaptee) {
this.adaptee = adaptee;
}
public void actionPerformed(ActionEvent e) {
adaptee.jButton1_actionPerformed(e);
}
}
package untitled5;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import com.borland.jbcl.layout.*;
/**
* pTitle: /p
* pDescription: /p
* pCopyright: Copyright ? 2003/p
* pCompany: /p
* @author not attributable
* @version 1.0
*/
public class retur extends JFrame {
JPanel contentPane;
XYLayout xYLayout1 = new XYLayout();
JLabel jLabel1 = new JLabel();
//Construct the frame
public retur() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
}
}
//Component initialization
private void jbInit() throws Exception {
contentPane = (JPanel) this.getContentPane();
jLabel1.setFont(new java.awt.Font("SansSerif", 0, 20));
jLabel1.setForeground(Color.red);
jLabel1.setText("超市管理系统");
contentPane.setLayout(xYLayout1);
this.setSize(new Dimension(400, 300));
this.setTitle("超市管理系统");
contentPane.add(jLabel1, new XYConstraints(139, 1, 126, 33));
}
//Overridden so we can exit when window is closed
protected void processWindowEvent(WindowEvent e) {
super.processWindowEvent(e);
if (e.getID() == WindowEvent.WINDOW_CLOSING) {
System.exit(0);
}
}
}
package untitled5;
import java.io.*;
import java.net.*;
import java.sql.*;
import java.lang.*;
import javax.sql.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import com.borland.jbcl.layout.*;
import com.borland.dbswing.*;
//货品信息登记
public class Frame2 extends JFrame {
JPanel contentPane;
JLabel jLabel1 = new JLabel();
XYLayout xYLayout1 = new XYLayout();
JLabel jLabel2 = new JLabel();
JLabel jLabel3 = new JLabel();
JTextField jTextField1 = new JTextField();
JLabel jLabel4 = new JLabel();
JTextField jTextField2 = new JTextField();
JPanel jPanel1 = new JPanel();
XYLayout xYLayout2 = new XYLayout();
JScrollPane jScrollPane1 = new JScrollPane();
JLabel jLabel5 = new JLabel();
JTextField jTextField3 = new JTextField();
//Construct the frame
public Frame2() {
enableEvents(AWTEvent.WINDOW_EVENT_MASK);
try {
jbInit();
}
catch(Exception e) {
e.printStackTrace();
}
}
//Component initialization
private void jbInit() throws Exception {
contentPane = (JPanel) this.getContentPane();
contentPane.setLayout(xYLayout1);
this.setSize(new Dimension(600, 500));
this.setTitle("超市管理系统");
this.addHierarchyBoundsListener(new Frame2_this_hierarchyBoundsAdapter(this));
jLabel1.setFont(new java.awt.Font("SansSerif", 0, 25));
jLabel1.setForeground(Color.red);
jLabel1.setText("超市管理系统");
contentPane.setForeground(Color.black);
jLabel2.setFont(new java.awt.Font("SansSerif", 0, 30));
jLabel2.setText("产 品 信 息 展 示");
// statusBar.setFont(new java.awt.Font("SansSerif", 0, 20));
jLabel3.setFont(new java.awt.Font("SansSerif", 0, 20));
jLabel3.setText("产品名称");
jTextField1.setText("");
jLabel4.setEnabled(true);
jLabel4.setFont(new java.awt.Font("SansSerif", 0, 20));
jLabel4.setText("产品ID号");
jTextField2.setText("");
jTextField2.addActionListener(new Frame2_jTextField2_actionAdapter(this));
jPanel1.setLayout(xYLayout2);
jLabel5.setFont(new java.awt.Font("SansSerif", 0, 25));
jLabel5.setForeground(Color.red);
jLabel5.setText("该产品详细信息");
jTextField3.setText("");
contentPane.add(jLabel1, new XYConstraints(237, 0, 153, 40));
contentPane.add(jLabel2, new XYConstraints(200, 47, 231, 58));
contentPane.add(jLabel3, new XYConstraints(47, 102, 101, 42));
contentPane.add(jTextField1, new XYConstraints(128, 108, 112, 34));
contentPane.add(jTextField2, new XYConstraints(361, 107, 109, 36));
contentPane.add(jPanel1, new XYConstraints(75, 166, 453, 277));
jPanel1.add(jScrollPane1, new XYConstraints(14, 8, 433, 221));
jScrollPane1.getViewport().add(jTextField3, null);
jPanel1.add(jLabel5, new XYConstraints(112, 240, -1, -1));
contentPane.add(jLabel4, new XYConstraints(278, 111, -1, -1));
}
//Overridden so we can exit when window is closed
protected void processWindowEvent(WindowEvent e) {
super.processWindowEvent(e);
if (e.getID() == WindowEvent.WINDOW_CLOSING) {
System.exit(0);
}
}
void Select() {
try {
String str1, str2;
str1 = jTextField1.getText();
str2 = jTextField2.getText();
有谁有用JAVA编写的小型超市管理系统的源代码啊 数据库用mysql 急啊【java水果超市登陆代码 java水果系统】作业吧？找个类似的图书馆一类的东西改一下数据库不就行了？
数据库如何用java写超市购物程序？要使用Java编写超市购物程序 ， 您需要使用Java数据库编程技术来连接到您的数据库并执行相关的数据库操作 。在Java中，您可以使用JDBC（Java数据库连接）API来连接到数据库并执行SQL语句 。例如，您可以使用JDBC API来执行以下操作：
创建数据库连接
执行增删改查（CRUD）操作
提交或回滚事务
执行存储过程和函数
查询数据库元数据
此外，您还可以使用Java的面向对象编程技术来封装数据库操作，以便更方便地在您的程序中使用 。例如 ， 您可以创建一个类来表示超市商品 ， 并定义一些方法来执行商品的增删改查操作 。这样，您就可以在程序中通过调用这些方法来简单地完成对数据库的操作，而不需要编写复杂的SQL语句 。
java程序编写，显示水果的订购详情，定义一个带有参数的构造方法，这些参数用于存放产品，数量和价格public class ShuiGuo{
private String chanpin;
private int number;
private float price;
public ShuiGuo(String chanpin,int number,float price){
this.chanpin = chanpin;
this.number = number ;
this.price = price;
}
//省略get.set方法
}
最后的需求没看懂 。是说自己输入水果之后，在来取3种不同的吗
java超市计价系统代码package entity;
public class Market {
private int id;//id
private int num;//数量
private String goods;//商品
private double price;//价格

public Market(int id, int num, String goods, double price) {
super();
this.id = id;
this.num = num;
this.goods = goods;
this.price = price;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public int getNum() {
return num;
}
public void setNum(int num) {
this.num = num;
}
public String getGoods() {
return goods;
}
public void setGoods(String goods) {
this.goods = goods;
}
public double getPrice() {
return price;
}
public void setPrice(double price) {
this.price = price;
}
public double calc( ){
double sum=price*num;
System.out.println("您消费共计：" sum "￥");
return sum;
}
}
package test;
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;
import entity.Market;
public class Test {
private static MapInteger,Market goods=new HashMapInteger, Market();
public static void main(String[] args) {
System.out.println("-------超市计价系统-------");
String goods1="可口可乐";
String goods2="爆米花";
String goods3="益达";
printTable("编号","商品","价格");
printTable("1",goods1,"3.0￥");
printTable("2",goods2,"5.0￥");
printTable("3",goods3,"10.0￥");
goods.put(1, new Market(1, 1, goods1, 3.0));
goods.put(2, new Market(2, 1,goods2, 5.0));
goods.put(3, new Market(3, 1, goods3, 10.0));
Scanner input = new Scanner(System.in);
System.out.println("请输入商品的编号:");
int num = input.nextInt();
System.out.println("请输入商品的数量");
int amount = input.nextInt();
Market market = goods.get(num);
market.setNum(amount);
market.calc();
}
private static void printTable(String row1,String row2,String row3 ) {
System.out.print(row1);
int times=12;
if (row2!="商品") {
times=5;
}
for (int i = 0; itimes; i) {
System.out.print(" ");
}
System.out.print(row2);
for (int i = 0; i10; i) {
System.out.print(" ");
}
System.out.print(row3);
System.out.println("\n");
}
}
//测试结果：
-------超市计价系统-------
编号商品价格
1可口可乐3.0￥
2爆米花5.0￥
3益达10.0￥
请输入商品的编号:
3
请输入商品的数量
5
您消费共计：50.0￥
java水果超市登陆代码的介绍就聊到这里吧，感谢你花时间阅读本站内容，更多关于java水果系统、java水果超市登陆代码的信息别忘了在本站进行查找喔 。

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