下面是一个简单的登录示例：
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代码复制展示：
public class ATMLogin {
public static void main(String[] args) {
// 设置用户名和密码
String username = "gqk";
String password = "520";
// 最多可以登录 3 次
for (int i = 0; i 3; i++) {
// 读取用户输入的用户名和密码
Scanner in = new Scanner(System.in);
System.out.print("请输入用户名：");
String inputUsername = in.nextLine();
System.out.print("请输入密码：");
String inputPassword = in.nextLine();
// 检查用户名和密码是否正确
if (inputUsername.equals(username) inputPassword.equals(password)) {
System.out.println("欢迎" + username + "登录！");
break; // 登录成功，退出循环
} else {
System.out.println("用户名或密码错误，请重新输入！");
}
}
// 如果 3 次登录都失败，则提示用户
System.out.println("卡片已经被锁，请联系客服人员！");
}
}
回答不易望请采纳
首先是Token主类。类很简单
package com.company.util;
import java.util.ArrayList;
import javax.servlet.http.HttpSession;
public class Token {
private static final String TOKEN_LIST_NAME = "tokenList";
public static final String TOKEN_STRING_NAME = "token";
private static ArrayList getTokenList(HttpSession session) {
Object obj = session.getAttribute(TOKEN_LIST_NAME);
if (obj != null) {
return (ArrayList) obj;
} else {
ArrayList tokenList = new ArrayList();
session.setAttribute(TOKEN_LIST_NAME, tokenList);
return tokenList;
}
}
private static void saveTokenString(String tokenStr, HttpSession session) {
ArrayList tokenList = getTokenList(session);
tokenList.add(tokenStr);
session.setAttribute(TOKEN_LIST_NAME, tokenList);
}
private static String generateTokenString(){
return new Long(System.currentTimeMillis()).toString();
}
/** *//**
* Generate a token string, and save the string in session, then return the token string.
*
* @param HttpSession
* session
* @return a token string used for enforcing a single request for a particular transaction.
*/
public static String getTokenString(HttpSession session) {
String tokenStr = generateTokenString();
saveTokenString(tokenStr, session);
return tokenStr;
}
/** *//**
* check whether token string is valid. if session contains the token string, return true.
* otherwise, return false.
*
* @param String
* tokenStr
* @param HttpSession
* session
* @return true: session contains tokenStr; false: session is null or tokenStr is id not in session
*/
public static boolean isTokenStringValid(String tokenStr, HttpSession session) {
boolean valid = false;
if(session != null){
ArrayList tokenList = getTokenList(session);
if (tokenList.contains(tokenStr)) {
valid = true;
tokenList.remove(tokenStr);
}
}
return valid;
}
}
在jsp页面端。
首先import该类：
%@ page import="com.company.util.Token" %
表单包含隐藏的token字符串:
form
input type="hidden" name="%=Token.TOKEN_STRING_NAME %" value="%=Token.getTokenString(session) %"
/form
在Servlet中添加如下代码。
if(Token.isTokenStringValid(request.getParameter(Token.TOKEN_STRING_NAME), request.getSession())){
//进行正常业务流程
你要先学会截图哦,你发的看不清楚,重新写了一个你参考参考!
import java.awt.GridLayout;
import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
public class Day30A extends JFrame {
private static final long serialVersionUID = 1L;
private JLabel labelName,labelId,labelPass,labelMoney,labelSelect,labelCar;
private JComboBoxString jcb;
private JPanel jp1,jp2,jp3,jp4,jp5,jp6,jp7;
private ButtonGroup btg;
private JRadioButton jr1,jr2;
Day30A(){
this.setTitle("注册账户");
this.setLayout(new GridLayout(7,1));
this.setSize(300,280);
this.setLocationRelativeTo(null);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
init();
this.setVisible(true);
}
private void init() {
String str="卡片类型1,卡片类型2,卡片类型3,卡片类型4,卡片类型5";
jcb=new JComboBox(str.split(","));
labelId=new JLabel("账号: ");
labelName=new JLabel("姓名: ");
labelPass=new JLabel("密码: ");
labelMoney=new JLabel("开户金额:");
labelSelect=new JLabel("存款类型:");
labelCar=new JLabel("卡片类型:");
addFun1();
addFun2();
}
private void addFun2() {
this.add(jp1);
this.add(jp2);
this.add(jp3);
this.add(jp4);
this.add(jp5);
this.add(jp6);
this.add(jp7);
}
private void addFun1() {
jp1=new JPanel();
jp1.add(labelId);
jp1.add(new JTextField(15));
jp2=new JPanel();
jp2.add(labelName);
jp2.add(new JTextField(15));
jp3=new JPanel();
jp3.add(labelPass);
jp3.add(new JTextField(15));
jp4=new JPanel();
jp4.add(labelMoney);
jp4.add(new JTextField(13));
jp5=new JPanel();
jp5.add(labelSelect);
btg=new ButtonGroup();
jr1=new JRadioButton("定期");
jr2=new JRadioButton("活期",true);
btg.add(jr1);
btg.add(jr2);
jp5.add(jr1);
jp5.add(jr2);
jp6=new JPanel();
jp6.add(labelCar);
jp6.add(jcb);
jp7=new JPanel();
jp7.add(new JButton("确定"));
jp7.add(new JButton("取消"));
}
public static void main(String[] args) {
new Day30A();
}
}
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.sql.*;
class LoginFrm extends JFrame implements ActionListener
{
JLabel lbl1=new JLabel("用户名");
JLabel lbl2=new JLabel("密码");
JTextField txt=new JTextField(15);
JPasswordField pf=new JPasswordField();
JButton btn1=new JButton("确定");
JButton btn2=new JButton("取消");
public LoginFrm()
{
this.setTitle("登陆");
JPanel jp=(JPanel)this.getContentPane();
jp.setLayout(new GridLayout(3,2,10,10));
jp.add(lbl1);jp.add(txt);
jp.add(lbl2);jp.add(pf);
jp.add(btn1);jp.add(btn2);
btn1.addActionListener(this);
btn2.addActionListener(this);
}
public void actionPerformed(ActionEvent ae)
{
if(ae.getSource()==btn1)
{
try
{
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver")；
Connection con=DriverManager.getConnection("jdbc:odbc:MyDB","","");
Statement cmd=con.createStatement();
ResultSet rs=cmd.executeQuery("select * from loginAndpassword where login='"+txt.getText()+"' and password='"+pf.getText()+"'");
if(rs.next())
{
JOptionPane.showMessageDialog(null,"登陆成功！");
}
else
JOptionPane.showMessageDialog(null,"用户名或密码错误！");
} catch(Exception ex){}
if(ae.getSource()==btn2)
{
txt.setText("");
pf.setText("");
}
}
}
public static void main(String arg[])
{
JFrame.setDefaultLookAndFeelDecorated(true);
LoginFrm frm=new LoginFrm();
frm.setSize(400,200);
frm.setVisible(true);
}
}
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
public class Test26 {
public static void main(String[] args) {
final String userName = "abc";
final String passwrod = "123";
JFrame jFrame = new JFrame("登陆界面");
Dimension dimension = Toolkit.getDefaultToolkit().getScreenSize();
jFrame.setBounds(((int)dimension.getWidth() - 200) / 2, ((int)dimension.getHeight() - 300) / 2, 200, 150);
jFrame.setResizable(false);
jFrame.setLayout(null);
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel label1 = new JLabel("姓名");
label1.setBounds(10, 10, 100, 30);
jFrame.add(label1);
JLabel label2 = new JLabel("密码");
label2.setBounds(10, 40, 100, 30);
jFrame.add(label2);
final JTextField text1 = new JTextField();
text1.setBounds(50, 15, 130, 20);
jFrame.add(text1);
final JPasswordField text2 = new JPasswordField();
text2.setBounds(50, 45, 130, 20);
jFrame.add(text2);
JButton button = new JButton("Login");
button.setBounds(10, 75, 170, 40);
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
if(userName.equals(text1.getText()) passwrod.equals(text2.getText())) {
JOptionPane.showMessageDialog(null, "登陆成功误", "提示", JOptionPane.INFORMATION_MESSAGE);
} else {
JOptionPane.showMessageDialog(null, "错误", "提示", JOptionPane.ERROR_MESSAGE);
text1.setText("");
text2.setText("");
}
}
});
jFrame.add(button);
jFrame.setVisible(true);
}
}
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