java登录

A. 用java实现一个登录页面 可以用什么方法

那应该用jsp页面里写一个表单，主要包括用户名、密码等字段，然后再写一个提交和重置按钮，采用post或者get方式把表单数据提交到后台进行处理，比如说通过java的jdbc访问数据库，判断输入表单的数据是否是已经存在的合法用户，如果是就跳转到系统主页面，如果不是就显示提示错误信息。

B. 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);

}
}

C. 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

D. java注册登录

不清楚LZ的意思，不连接数据库么？

E. 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！！！

F. 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；

  

G. 用JAVA编写一个登陆系统。

第一个java文件LogoingDemo.java

importjava.util.Scanner;

publicclassLogoingDemo{
	publicstaticvoidmain(String[]args){
		System.out.println("请输入用户名");
		Scannersc=newScanner(System.in);
		Stringname=sc.nextLine();
		System.out.println("请输入密码");
		Stringpsw=sc.nextLine();
		sc.close();
		CheckDemocd=newCheckDemo(name,psw);//用户名和密码传入验证类
		booleanbo=cd.check();//调用方法进行验证
		if(bo){
			System.out.println("登录成功");
		}else{
			System.out.println("登录失败:提示用户名admin密码123");
		}
	}
}

第二个java文件CheckDemo.java

publicclassCheckDemo{
	publicStringname;
	publicStringpsw;
	publicCheckDemo(Stringname,Stringpsw){//构造器
		this.name=name;
		this.psw=psw;
	}
	publicbooleancheck(){
		//用户名密码不能为空.用户名=admin密码=123
		if(name!=null&&psw!=null&&name.equals("admin")&&psw.equals("123")){
			returntrue;
		}
		returnfalse;
	}
}

效果

请输入用户名
admin
请输入密码
123
登录成功
------------------------------------
请输入用户名
add
请输入密码
123
登录失败:提示用户名admin密码123

H. 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();
}
}

I. 如何用java做登录界面

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();
}
}

J. 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);
}

}