登录java

A. java编写用户登录

代码发给你，如果什么都不懂的话，估计你也难以运行成功，而且图片也没有，要自己会改就能运行了。这些代码希望能帮到你！

数据库文件：

create database hotel_Flyer
go

use hotel_Flyer

create table userInfo(
id int primary key identity(1,1),
userName varchar(20),
password varchar(10),
realName nvarchar(20),
sex nvarchar(2),
age int,
favorite nvarchar(100),
telNum varchar(12),
email varchar(50),
address nvarchar(200)
)
go
insert into userInfo(userName,password) values('李连杰','123')
insert into userInfo(userName,password) values('成龙','123')
insert into userInfo(userName,password) values('甄子丹','123')
insert into userInfo(userName,password) values('赵文卓','123')
insert into userInfo(userName,password) values('吴京','123')
insert into userInfo(userName,password) values('周星驰','123')
insert into userInfo(userName,password) values('刘德华','123')

加载驱动类：

public class ConTosql {
Connection con=null;
public Connection getConnection() throws Exception{
Class.forName("com.microsoft.jdbc.sqlserver.SQLServerDriver");
con= DriverManager.getConnection("jdbc:microsoft:sqlserver://localhost:1433;databaseName=hotel_Flyer", "sa", "sa");
return con;
}

}

连接数据库类：

public class DengluUC {
Connection con=null;
PreparedStatement stm=null;
ResultSet rs=null;

public boolean checkUser(String user,String pwd){
boolean tof=false;
try {

ConToSQL cts=new ConToSQL();
con=cts.getConnection();
stm=con.prepareStatement("select password from userInfo where userName=?");
stm.setString(1, user);
rs=stm.executeQuery();
if(rs.next()){
if(rs.getString(1).equals(pwd)){
tof= true;
}
}

} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
} /*finally{
try {
rs.close();
stm.close();
con.close();
} catch (SQLException e) {
e.printStackTrace();
}
return tof;
}*/
return tof;
}
}

登录类代码：

package com.hbsoft.hotel_Flyer.login;
import com.hbsoft.hotel_Flyer.usermanagerForm.*;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.Timer;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridBagLayout;
import java.awt.Rectangle;
import javax.swing.BorderFactory;
import java.awt.Color;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.swing.JComboBox;
import javax.swing.JOptionPane;
import javax.swing.JPasswordField;
import javax.swing.JButton;
import javax.swing.ImageIcon;
import javax.swing.JTextField;
import javax.swing.text.html.Option;

import com.hbsoft.hotel_Flyer.proc.Process;

import java.awt.Point;
import java.sql.*;

import com.hbsoft.hotel_Flyer.database.*;

public class Denglu {

private JFrame jFrame = null; // @jve:decl-index=0:visual-constraint="61,26"
private JPanel jContentPane = null;
private JPanel jPanel = null;
private JComboBox jComboBox = null;
private JLabel jL4 = null;
private JLabel jLabel1 = null;
private JPasswordField jPasswordField = null;
private JButton jB1 = null;
private JButton jB2 = null;
private JComboBox jComboBox1 = null;
private JLabel jLabel = null;
private JLabel jLabel2 = null;
private Connection con=null; // @jve:decl-index=0:
private Statement sts=null;
private ResultSet rs=null;
private DatabaseMetaData dmd=null;
private int rowCount=0;
/**
* This method initializes jFrame
*
* @return javax.swing.JFrame
*/
public JFrame getJFrame() {
if (jFrame == null) {
jFrame = new JFrame("系统登陆");
jFrame.setSize(new Dimension(854, 539));
jFrame.setLocation(new Point(100, 100));
jFrame.setContentPane(getJContentPane());
jFrame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jFrame.setResizable(false);
}
return jFrame;
}

/**
* This method initializes jContentPane
*
* @return javax.swing.JPanel
*/
private JPanel getJContentPane() {
if (jContentPane == null) {
jLabel2 = new JLabel();
jLabel2.setBounds(new Rectangle(3, 4, 845, 503));
jLabel2.setIcon(new ImageIcon("E:/java\uff088\uff09\u73ed\u5468\u67ab/\u7b2c\u5341\u7ec4\u5de5\u4f5c\u7ad9/hotel_Flyer/\u767b\u5f55\u80cc\u666f.jpg"));
jLabel2.setText("");
jLabel = new JLabel();
jLabel.setText("");
jLabel.setIcon(new ImageIcon(getClass().getResource("/com/hbsoft/hotel_Flyer/img/\u767b\u5f55\u80cc\u666f.jpg")));
jLabel.setBounds(new Rectangle(-1, 1, 851, 509));
jLabel1 = new JLabel();
jLabel1.setBounds(new Rectangle(438, 141, 363, 231));
jLabel1.setText("");
jL4 = new JLabel();
jL4.setBounds(new Rectangle(484, 341, 289, 28));
jL4.setHorizontalAlignment(SwingConstants.CENTER);
Timer t =new Timer(1000,new ActionListener(){
public void actionPerformed(ActionEvent e) {
Date d=new Date();
SimpleDateFormat df = new SimpleDateFormat("yy-MM-dd hh:mm:ss");
jL4.setText(df.format(d));
}
});
t.start();
jContentPane = new JPanel();
jContentPane.setLayout(null);
jContentPane.setBorder(BorderFactory.createLineBorder(Color.cyan, 2));
jContentPane.setFont(new Font("\u96b6\u4e66", Font.PLAIN, 14));
jContentPane.add(getJPanel(), null);
jContentPane.add(jL4, null);
jContentPane.add(jLabel1, null);
jContentPane.add(getJPasswordField(), null);
jContentPane.add(getJB1(), null);
jContentPane.add(getJB2(), null);
jContentPane.add(getJComboBox1(), null);
jContentPane.add(jLabel, null);
jContentPane.add(jLabel2, null);
jContentPane.add(jLabel, null);
}
return jContentPane;
}

/**
* This method initializes jPanel
*
* @return javax.swing.JPanel
*/
private JPanel getJPanel() {
if (jPanel == null) {
jPanel = new JPanel();
jPanel.setLayout(new GridBagLayout());
jPanel.setBounds(new Rectangle(0, 0, 415, 0));
}
return jPanel;
}
/**
* This method initializes jB1
*
* @return javax.swing.JButton
*/
void ThisDispose(){
this.getJFrame().dispose();
}
/**
* This method initializes jPasswordField
*
* @return javax.swing.JPasswordField
*/
private JPasswordField getJPasswordField() {
if (jPasswordField == null) {
jPasswordField = new JPasswordField();
jPasswordField.setBounds(new Rectangle(570, 263, 201, 29));
}
return jPasswordField;
}

/**
* This method initializes jB1
*
* @return javax.swing.JButton
*/
/*void ThisdDispose(){
this.getJFrame().dispose();
}*/
private JButton getJB1() {
if (jB1 == null) {
jB1 = new JButton();
jB1.setBounds(new Rectangle(489, 313, 103, 35));
jB1.setText("登陆");
jB1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent e) {
if(new DengluUC().checkUser(jComboBox1.getSelectedItem().toString(), new String(jPasswordField.getPassword()))){
//message.setText("登录成功");
//message.setForeground(new Color(255,0,0));
new Process((String)jComboBox1.getSelectedItem()).setVisible(true);
ThisDispose();

}else{
if(new String(jPasswordField.getPassword()).length()==0){
JOptionPane.showMessageDialog(null, "密码不能为空");
}else{
JOptionPane.showMessageDialog(null, "密码不正确，请重新输入");
}
}

}
});
}
return jB1;
}

/**
* This method initializes jB2
*
* @return javax.swing.JButton
*/
private JButton getJB2() {
if (jB2 == null) {
jB2 = new JButton();
jB2.setBounds(new Rectangle(642, 312, 103, 35));
jB2.setText("退出");
jB2.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent e) {
System.exit(0);
}
});
}
return jB2;
}

/**
* This method initializes jComboBox1
*
* @return javax.swing.JComboBox
*/
public void getResultSet(){
try{
con=new ConToSQL().getConnection();
sts=con.createStatement();
rs=sts.executeQuery("select * from userInfo");

}catch(Exception e){
e.printStackTrace();
}

}
public int getRowCount(){
try {
rs.last();
if (rs.isLast()) {
rowCount = rs.getRow();
}
} catch (Exception e) {
e.printStackTrace();
}
return rowCount;
}
public void closeData(){
try{
rs.close();
sts.close();
con.close();
}catch(SQLException e){
e.printStackTrace();
}
}
private JComboBox getJComboBox1() {
getResultSet();
String [] arr=new String[7];
int i=0;
try {
while (rs.next()) {
if(i<arr.length){
arr[i] = rs.getString(2);
i++;}
}
} catch (Exception e) {
e.printStackTrace();
}
if (jComboBox1 == null) {
jComboBox1 = new JComboBox(arr);
closeData();
jComboBox1.setBounds(new Rectangle(569, 218, 201, 29));
}
return jComboBox1;
}

public static void main(String [] args) throws Exception{
// javax.swing.UIManager.setLookAndFeel("com.jtattoo.plaf.mcwin.McWinLookAndFeel");
javax.swing.UIManager.setLookAndFeel("com.jtattoo.plaf.acryl.AcrylLookAndFeel");
new Denglu().getJFrame().setVisible(true);
}

}

B. 用java编程实现用户注册并进行登录操作

String username = "",password = "",passwordagain = ""; // 定义用户名和密码

将该变量等于为全局变量 或局部变量即可

C. java登录方法

jsp中用form标签
<form action="login.do" method="get">
<input type="text" name="name"/>
<input type="text" name="password"/>
<input type="submit" value="submit"/>
</form>
login.java //此为servlet类
doGet(.......){
String name=request.getParamater("name");//获得jsp页面传过来的name值
}

然后再web.xml中配置servlet就行了

希望能帮到你！

D. 登录界面的java代码，分别有教师登录，管理员登录，学生登录，右边是用户名和密码，见图。

分三个包，自己建个包，导进去就ok了，数据库是access的。
package 登录;

import java.awt.EventQueue;

public class Cilent {

private JFrame frame;
private JTextField textField;
private JPasswordField passwordField;

/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Cilent window = new Cilent();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}

/**
* Create the application.
*/
public Cilent() {
initialize();
}

/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setTitle("登陆界面");
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
frame.setResizable(false);

JLabel lblNewLabel = new JLabel("用户名");
lblNewLabel.setBounds(38, 43, 80, 34);
frame.getContentPane().add(lblNewLabel);

textField = new JTextField();
textField.setBounds(155, 42, 227, 37);
frame.getContentPane().add(textField);
textField.setColumns(10);

JLabel label = new JLabel("密码");
label.setBounds(38, 115, 80, 34);
frame.getContentPane().add(label);

passwordField = new JPasswordField();
passwordField.setBounds(155, 115, 227, 37);
frame.getContentPane().add(passwordField);

JButton btnNewButton = new JButton("登录");
btnNewButton.setBounds(60, 187, 115, 34);
frame.getContentPane().add(btnNewButton);
btnNewButton.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
UserCheck UC=new UserCheck(textField.getText(),String.valueOf(passwordField.getPassword()));
if(UC.getI()!=0) //有此用户
{
frame.setVisible(false);
}
else
{
textField.setText("");
passwordField.setText("");
}
}
});

JButton button = new JButton("取消");
button.setBounds(242, 187, 115, 34);
frame.getContentPane().add(button);
button.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
textField.setText("");
passwordField.setText("");
}
});
}
}
/*****************************************************************/
package 登录;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

import 操作处理.UsersCL;

/**@author 20111024
* 检测登录的用户在数据库中有无，若没有，则提示没有此用户，
* 若有，则判断级别：普通用户还是管理员。
*/
public class UserCheck {

private int i=0; //用户级别:0不是用户、1是管理员、2是普通用户
UserCheck(String name ,String password)
{
String jdriver="sun.jdbc.odbc.JdbcOdbcDriver";
String connectDB="jdbc:odbc:Students";
Statement stmt=null;
ResultSet rs=null;
Connection con=null;
try {
Class.forName(jdriver);
con=DriverManager.getConnection(connectDB);
stmt=con.createStatement();
String query="select * from users where name='"+name+"' and passwd='"+password+"'";

rs=stmt.executeQuery(query);
if(rs.next())
{
//数据库中有此用户，访问成功
i=Integer.parseInt(rs.getString(3));
UsersCL UL=new UsersCL(i);
}
else
{
i=0; //没有用户是默认是0级
}
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public int getI() {
return i;
}
}
/********************************************************************************************/
package 操作处理;

import java.awt.EventQueue;

public class UsersCL implements ActionListener{

private JFrame frame;
private JTextField textField;
private JTextField textField_1;
private JTextField textField_2;
private JTextField textField_3;
private int i=0;
private JLabel label_3;
private JTextField textField_4;
public UsersCL(int i) {
this.i=i;
frame = new JFrame();
frame.setTitle("用户处理界面");
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
frame.setResizable(false);
frame.setVisible(true);

JLabel lblNewLabel = new JLabel("学号");
lblNewLabel.setBounds(24, 32, 74, 29);
frame.getContentPane().add(lblNewLabel);

JLabel label = new JLabel("姓名");
label.setBounds(24, 71, 74, 29);
frame.getContentPane().add(label);

JLabel label_1 = new JLabel("年龄");
label_1.setBounds(24, 110, 74, 29);
frame.getContentPane().add(label_1);

label_3 = new JLabel("性别");
label_3.setBounds(24, 149, 74, 29);
frame.getContentPane().add(label_3);

JLabel label_2 = new JLabel("状态");
label_2.setBounds(24, 195, 74, 29);
frame.getContentPane().add(label_2);

textField = new JTextField();
textField.setBounds(101, 34, 113, 25);
frame.getContentPane().add(textField);
textField.setColumns(10);

textField_1 = new JTextField();
textField_1.setColumns(10);
textField_1.setBounds(101, 73, 113, 25);
frame.getContentPane().add(textField_1);

textField_2 = new JTextField();
textField_2.setColumns(10);
textField_2.setBounds(101, 112, 113, 25);
frame.getContentPane().add(textField_2);

textField_3 = new JTextField();
textField_3.setEditable(false);
textField_3.setColumns(10);
textField_3.setBounds(101, 199, 288, 25);
frame.getContentPane().add(textField_3);

textField_4 = new JTextField();
textField_4.setColumns(10);
textField_4.setBounds(101, 149, 113, 25);
frame.getContentPane().add(textField_4);

if(1==i)
{
JButton btnNewButton = new JButton("追加");
btnNewButton.setBounds(276, 41, 113, 29);
frame.getContentPane().add(btnNewButton);
btnNewButton.addActionListener(this);
btnNewButton.setActionCommand("追加");

JButton button_1 = new JButton("删除");
button_1.setBounds(276, 145, 113, 29);
frame.getContentPane().add(button_1);
button_1.addActionListener(this);
button_1.setActionCommand("删除");
}

JButton button = new JButton("查询");
button.setBounds(276, 91, 113, 29);
frame.getContentPane().add(button);
button.addActionListener(this);
button.setActionCommand("查询");
}
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String name,age,sex,query=null;
int num,age1,count=0;
num=Integer.parseInt(textField.getText());
name=textField_1.getText();
age1=Integer.parseInt(textField_2.getText());
sex=textField_4.getText();

if(e.getActionCommand().equals("追加"))
{
query="insert into students values("+num+","+"'"+name+"',"+age1+",'"+sex+"');";
count=1;
}
else if(e.getActionCommand().equals("查询"))
{
query="select * from students where XSB="+num+";";
count=2;
}
else if(e.getActionCommand().equals("删除"))
{
query="delete from students where XSB="+num+" and name="+"'"+name+"'";
count=3;
}

Statement stmt=null;
ResultSet rs=null;
Connection con=null;
String jdriver="sun.jdbc.odbc.JdbcOdbcDriver";
String connectDB="jdbc:odbc:Students";
String query1=null;
try {
Class.forName(jdriver);
con=DriverManager.getConnection(connectDB);
stmt=con.createStatement();
if(count==1)
{
query1="select * from students where XSB="+num+";";
rs=stmt.executeQuery(query1);
if(rs.next())
textField_3.setText("已经由此记录，不能追加！");
else
{
stmt.executeUpdate(query);
textField_3.setText("已经追加完成！");
}
}
else if(2==count)
{
stmt.executeQuery(query);
rs=stmt.executeQuery(query);
if(rs.next())
{
textField_3.setText("已查找到此记录！");
}
else
{
textField_3.setText("没有此记录，可以追加！");
}
}
else if(3==count)
{
query1="select * from students where XSB="+num+" and name="+"'"+name+"'";
rs=stmt.executeQuery(query1);
if(rs.next())
{
stmt.executeUpdate(query);
textField_3.setText("已删除此记录！");
}
else
textField_3.setText("无此记录！");
}
} catch (ClassNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
finally{
//关闭资源
if(stmt!=null){
try {
stmt.close();
} catch (Exception e2) {
// TODO: handle exception
}
stmt=null;
}
if(con!=null){
try {
con.close();
} catch (Exception e2) {
// TODO: handle exception
}
con=null;
}
}
}
}

E. java实现简单登录界面

自己写的比较规范的代码，都有注释:

import javax.swing.JFrame;//框架
import javax.swing.JPanel;//面板
import javax.swing.JButton;//按钮
import javax.swing.JLabel;//标签
import javax.swing.JTextField;//文本框
import java.awt.Font;//字体
import java.awt.Color;//颜色
import javax.swing.JPasswordField;//密码框
import java.awt.event.ActionListener;//事件监听
import java.awt.event.ActionEvent;//事件处理
import javax.swing.JOptionPane;//消息窗口

public class UserLogIn extends JFrame{
public JPanel pnluser;
public JLabel lbluserLogIn;
public JLabel lbluserName;
public JLabel lbluserPWD;
public JTextField txtName;
public JPasswordField pwdPwd;
public JButton btnSub;
public JButton btnReset;

public UserLogIn(){
pnluser = new JPanel();
lbluserLogIn = new JLabel();
lbluserName = new JLabel();
lbluserPWD = new JLabel();
txtName = new JTextField();
pwdPwd = new JPasswordField();
btnSub = new JButton();
btnReset = new JButton();
userInit();
}

public void userInit(){
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//设置关闭框架的同时结束程序
this.setSize(300,200);//设置框架大小为长300,宽200
this.setResizable(false);//设置框架不可以改变大小
this.setTitle("用户登录");//设置框架标题
this.pnluser.setLayout(null);//设置面板布局管理
this.pnluser.setBackground(Color.cyan);//设置面板背景颜色
this.lbluserLogIn.setText("用户登录");//设置标签标题
this.lbluserLogIn.setFont(new Font("宋体",Font.BOLD | Font.ITALIC,14));//设置标签字体
this.lbluserLogIn.setForeground(Color.RED);//设置标签字体颜色
this.lbluserName.setText("用户名:");
this.lbluserPWD.setText("密 码:");
this.btnSub.setText("登录");
this.btnReset.setText("重置");
this.lbluserLogIn.setBounds(120,15,60,20);//设置标签x坐标120,y坐标15,长60,宽20
this.lbluserName.setBounds(50,55,60,20);
this.lbluserPWD.setBounds(50,85,60,25);
this.txtName.setBounds(110,55,120,20);
this.pwdPwd.setBounds(110,85,120,20);
this.btnSub.setBounds(85,120,60,20);
this.btnSub.addActionListener(new ActionListener()//匿名类实现ActionListener接口
{
public void actionPerformed(ActionEvent e){
btnsub_ActionEvent(e);
}
}
);
this.btnReset.setBounds(155,120,60,20);
this.btnReset.addActionListener(new ActionListener()//匿名类实现ActionListener接口
{
public void actionPerformed(ActionEvent e){
btnreset_ActionEvent(e);
}
}
);
this.pnluser.add(lbluserLogIn);//加载标签到面板
this.pnluser.add(lbluserName);
this.pnluser.add(lbluserPWD);
this.pnluser.add(txtName);
this.pnluser.add(pwdPwd);
this.pnluser.add(btnSub);
this.pnluser.add(btnReset);
this.add(pnluser);//加载面板到框架
this.setVisible(true);//设置框架可显
}

public void btnsub_ActionEvent(ActionEvent e){
String name = txtName.getText();
String pwd = String.valueOf(pwdPwd.getPassword());
if(name.equals("")){
JOptionPane.showMessageDialog(null,"账号不能为空","错误",JOptionPane.ERROR_MESSAGE);
return;
}else if (pwd.equals("")){
JOptionPane.showMessageDialog(null,"密码不能为空","错误",JOptionPane.ERROR_MESSAGE);
return;
}else if(true){
this.dispose();
}else{
JOptionPane.showMessageDialog(null,"账号或密码错误","错误",JOptionPane.ERROR_MESSAGE);
return;
}
}

public void btnreset_ActionEvent(ActionEvent e){
txtName.setText("");
pwdPwd.setText("");
}

public static void main(String[] args){
new UserLogIn();
}
}

F. java登录

sql语言自己写呗。。。

G. java编写一个用户注册及登录界面

mportjava.awt.HeadlessException;
importjava.awt.event.ActionEvent;
importjava.awt.event.ActionListener;

importjavax.swing.ImageIcon;
importjavax.swing.JButton;
importjavax.swing.JFrame;
importjavax.swing.JLabel;
importjavax.swing.JOptionPane;
importjavax.swing.JPanel;
importjavax.swing.JPasswordField;
importjavax.swing.JTextField;

@SuppressWarnings("serial")
{	
	JLabellbl1=newJLabel("用户名:");
	JLabellbl2=newJLabel("密码:");	
	JTextFieldtxt=newJTextField("admin",20);
	JPasswordFieldpwd=newJPasswordField(20);	
	JButtonbtn=newJButton("登录");	
	JPanelpnl=newJPanel();	
	privateinterror=0;
	
	publicMainFrame(Stringtitle)throwsHeadlessException{
		super(title);
		init();
	}

	privatevoidinit(){		
		this.setResizable(false);		
		
		pwd.setEchoChar('*');
		
		pnl.add(lbl1);
		pnl.add(txt);
		pnl.add(lbl2);
		pnl.add(pwd);
		pnl.add(btn);		
		this.getContentPane().add(pnl);
		
		btn.addActionListener(newActionListener(){			
			@Override
			publicvoidactionPerformed(ActionEvente){
				if("admin".equals(newString(pwd.getPassword()))){
					pnl.removeAll();
					JLabellbl3=newJLabel();
					ImageIconicon=newImageIcon(this.getClass().getResource("pic.jpg"));
					lbl3.setIcon(icon);
					pnl.add(lbl3);
				}
				else{
					if(error<3){
						JOptionPane.showMessageDialog(null,"密码输入错误，请再试一次");
						error++;
					}
					else{
						JOptionPane.showMessageDialog(null,"对不起，您不是合法用户");
						txt.setEnabled(false);
						pwd.setEnabled(false);
						btn.setEnabled(false);
					}
				}
			}
		});
	}	

	publicstaticvoidmain(String[]args){
		MainFramefrm=newMainFrame("测试");		
		frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frm.setBounds(100,100,300,120);
		frm.setVisible(true);
	}
}

H. java怎样实现登录验证

• 1.打开编程工具：

  打开java编程的界面，采用的是eclipse软件；

  

I. 用Java编写注册登录程序

什么都不说了 直接给你代码吧
package com.moliying.ui;
import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.List;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedWriter;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.Arrays;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
public class Login {
private JFrame frame = new JFrame("登录");
private Container c = frame.getContentPane();
private JTextField username = new JTextField();
private JPasswordField password = new JPasswordField();
private JButton ok = new JButton("确定");
private JButton cancel = new JButton("取消");
public Login() {
frame.setSize(300, 200);
frame.setBounds(450, 300, 300, 200);
c.setLayout(new BorderLayout());
initFrame();
frame.setVisible(true);
}
private void initFrame() {
// 顶部
JPanel titlePanel = new JPanel();
titlePanel.setLayout(new FlowLayout());
titlePanel.add(new JLabel("系统管理员登录"));
c.add(titlePanel, "North");
// 中部表单
JPanel fieldPanel = new JPanel();
fieldPanel.setLayout(null);
JLabel a1 = new JLabel("用户名:");
a1.setBounds(50, 20, 50, 20);
JLabel a2 = new JLabel("密 码:");
a2.setBounds(50, 60, 50, 20);
fieldPanel.add(a1);
fieldPanel.add(a2);
username.setBounds(110, 20, 120, 20);
password.setBounds(110, 60, 120, 20);
fieldPanel.add(username);
fieldPanel.add(password);
c.add(fieldPanel, "Center");
// 底部按钮
JPanel buttonPanel = new JPanel();
buttonPanel.setLayout(new FlowLayout());
buttonPanel.add(ok);
buttonPanel.add(cancel);
c.add(buttonPanel, "South");

ok.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
System.out.println(username.getText().toString());
}
});

cancel.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
frame.setVisible(false);
}
});
}
public static void main(String[] args) {
// new Login();

String ss = "abbabbbaabbbccba";

System.out.println(ss.split("b").length);

}
}

J. Java中登陆时如何实现的

如果时java web开发的话，那就是跟数据库挂钩了。用户输入用户名和密码，然后后台程序和数据库保存的用户名和密码进行比较，如果成功，就进入允许的界面，如果不成功，重新回到登录界面，或者返回网站首页。
希望能帮到你！！！