java怎么写登入代码
1.用java写一个登录界面的代码,哪位大神会啊,谢谢
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.(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); } }我有一个微信公众号,经常会分享一些Java技术相关的干货,还有一些学习资源。
如果你喜欢我的分享,可以用微信搜索“Java团长”或者“javatuanzhang”关注。
2.怎么用JAVA写一个用户登入程序
同意楼上的说法,具体点可以这样:创建一个用户表,里边包括LoginName(登录名),UserName(用户名),Password(密码),Age(年龄),Address(地址)。
然后编写Java程序(用MVC架构)模型层(M):DBConnection.java(负责连接数据库)import java.sql.Connection;import java.sql.DriverManager;import java.sql.*;public class DBConnection { private static final String DRIVER_CLASS = "sun.jdbc.odbc.JdbcOdbcDriver"; private static final String DB_URL = "jdbc:odbc:text"; public DBConnection() { } public static Connection getConnection() { Connection conn = null; try { Class.forName(DRIVER_CLASS); conn = DriverManager.getConnection(DB_URL); } catch (SQLException ex) { System.out.println(ex.getMessage()); } catch ( ex) { System.out.println(ex.getMessage()); } return conn; }}第2个负责数据库查询操作的类:DBUserManager.javaimport edu.systop.text.model.entity.User;import edu.systop.text.model.dao.DBConnection;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.DriverManager;import java.sql.*;public class DBUserManager { private static final String SQL_SELECT = "SELECT LoginName,UserName,PassWord,Age,Address FROM UserInfo WHERE LoginName = ? AND PassWord = ?"; public DBUserManager() { } public boolean checkDB(User u) { boolean b = false; Connection conn = null; PreparedStatement psmt = null; ResultSet rs = null; conn = DBConnection.getConnection(); try { psmt = conn.prepareStatement(SQL_SELECT); psmt.setString(1, u.getLoginName()); psmt.setString(2, u.getPassWord()); rs = psmt.executeQuery(); b = rs.next(); if (rs.next()) { b = true; } } catch (SQLException ex) { System.out.println(ex.getMessage()); } finally { cleanDB(rs, psmt, conn); } return b; } public User checkBC(User u) { Connection conn = null; PreparedStatement psmt = null; ResultSet rs = null; User tmp = new User(); conn = DBConnection.getConnection(); try { psmt = conn.prepareStatement(SQL_SELECT); psmt.setString(1, u.getLoginName()); psmt.setString(2, u.getPassWord()); rs = psmt.executeQuery(); if (rs.next()) { tmp.setLoginName(rs.getString(1)); tmp.setUserName(rs.getString(2)); tmp.setAge(rs.getInt(4)); tmp.setAddress(rs.getString(5)); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } finally { cleanDB(rs, psmt, conn); } return tmp; } public void cleanDB(ResultSet rs, PreparedStatement psmt, Connection conn) { try { if (rs != null) { rs.close(); } if (psmt != null) { psmt.close(); } if (conn != null) { conn.close(); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } }第3个实体用户类:User.javapackage edu.systop.text.model.entity;public class User { private String loginName; private String userName; private String passWord; private int age; private String address; public User() { } public void setLoginName(String loginName) { this.loginName = loginName; } public void setUserName(String userName) { this.userName = userName; } public void setPassWord(String passWord) { this.passWord = passWord; } public void setAge(int age) { this.age = age; } public void setAddress(String address) { this.address = address; } public String getLoginName() { return loginName; } public String getUserName() { return userName; } public String getPassWord() { return passWord; } public int getAge() { return age; } public String getAddress() { return address; }}然后编写控制层(C):GetInfoServlet.javapackage edu.systop.text.control;import javax.servlet.*;import javax.servlet.; charset=GBK"; //Initialize global variables public void init() throws ServletException { } //Process the HTTP Get request public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } //Process the HTTP Post request public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String loginName = request.getParameter("loginName"); String passWord = request.getParameter("passWord"); User u = new User(); u.setLoginName(loginName); u.setPassWord(passWord); UserManager m = new UserManager();RequestDispatcher d; if (m.checkUser(u)) { User o = m.checkBC(u); request.setAttribute("JavaBEAN",o); d = request.getRequestDispatcher("GetInfoUser.jsp"); } else { d = request。.。
3.JAVA中登录窗口设计,源代码该怎么写
import java.awt.*;import java.awt.event.*;import javax.swing.*;public class Test_Login extends javax.swing.JFrame {private JPanel jPanel1;private JButton bntLogin;private JButton bntCannel;private JPasswordField pwd;private JTextField username;private JLabel jLabel2;private JLabel jLabel1;public static void main(String[] args) { Test_Login inst = new Test_Login(); inst.setLocationRelativeTo(null); inst.setVisible(true);}public Test_Login() { super(); initGUI();}private void initGUI() { try { (WindowConstants.DISPOSE_ON_CLOSE); { jPanel1 = new JPanel(); getContentPane().add(jPanel1, BorderLayout.CENTER); jPanel1.setLayout(null); { jLabel1 = new JLabel(); jPanel1.add(jLabel1); jLabel1.setText("用户名"); jLabel1.setBounds(45, 30, 75, 25); } { jLabel2 = new JLabel(); jPanel1.add(jLabel2); jLabel2.setText("密码"); jLabel2.setBounds(45, 75, 55, 15); } { username = new JTextField(); jPanel1.add(username); username.setBounds(100, 30, 140, 25); } { pwd = new JPasswordField(); jPanel1.add(pwd); pwd.setBounds(100, 70, 140, 25); } { bntLogin = new JButton(); jPanel1.add(bntLogin); bntLogin.setText("登陆"); bntLogin.setBounds(40, 120, 60, 30); bntLogin.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { if (username.getText().equals("lisong") && pwd.getText().equals("lisong")) { JOptionPane.showMessageDialog(Test_Login.this, "登录成功"); } else { JOptionPane.showMessageDialog(Test_Login.this, "登录失败"); } } }); bntCannel = new JButton(); jPanel1.add(bntCannel); bntCannel.setText("取消"); bntCannel.setBounds(180, 120, 60, 30); bntCannel.addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { System.exit(0); } }); } } pack(); setSize(300, 215); } catch (Exception e) { e.printStackTrace(); }}}。
4.谁能写出JAVA中用户登陆的代码
import java.awt.*; import javax.swing.*; import java.awt.Rectangle; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import db.DBAccess; import java.sql.ResultSet; import java.sql.*; public class login extends JFrame { DBAccess da=new DBAccess(); public login() { try { jbInit(); } catch (Exception exception) { exception.printStackTrace(); } } private void jbInit() throws Exception { getContentPane().setLayout(null); jLabel3.setText("用户名"); jLabel3.setBounds(new Rectangle(50, 67, 89, 40)); uname.setBounds(new Rectangle(176, 67, 106, 37)); upwsd.setBounds(new Rectangle(170, 119, 106, 37)); jToggleButton1.setText("取消"); jToggleButton1.setBounds(new Rectangle(184, 214, 96, 32)); jToggleButton1.addActionListener(new login_jToggleButton1_actionAdapter(this)); jToggleButton2.setText("登陆"); jToggleButton2.setBounds(new Rectangle(39, 214, 96, 32)); jToggleButton2.addActionListener(new login_jToggleButton2_actionAdapter(this)); this.getContentPane().add(uname); this.getContentPane().add(upwsd); this.getContentPane().add(jToggleButton1); this.getContentPane().add(jToggleButton2); this.getContentPane().add(jLabel3); this.getContentPane().add(jLabel2); jLabel2.setText("密码"); jLabel2.setBounds(new Rectangle(47, 116, 89, 40)); } JLabel jLabel2 = new JLabel(); JLabel jLabel3 = new JLabel(); JTextField uname = new JTextField(); JTextField upwsd = new JTextField(); JToggleButton jToggleButton1 = new JToggleButton(); JToggleButton jToggleButton2 = new JToggleButton(); public void jToggleButton1_actionPerformed(ActionEvent e) { this.dispose(); } public void jToggleButton2_actionPerformed(ActionEvent e) { String name=uname.getText(); String pwsd=upwsd.getText(); try { ResultSet rs = da.getResultSet("select * from login where name='" + name + "' and pwsd='" + pwsd + "'"); if(rs.next()) { JOptionPane.showConfirmDialog(this,"登陆成功"); } else { JOptionPane.showConfirmDialog(this,"登陆失败"); } } catch (SQLException ex) { ex.printStackTrace(); } } } class login_jToggleButton2_actionAdapter implements ActionListener { private login adaptee; login_jToggleButton2_actionAdapter(login adaptee) { this.adaptee = adaptee; } public void actionPerformed(ActionEvent e) { adaptee.jToggleButton2_actionPerformed(e); } } class login_jToggleButton1_actionAdapter implements ActionListener { private login adaptee; login_jToggleButton1_actionAdapter(login adaptee) { this.adaptee = adaptee; } public void actionPerformed(ActionEvent e) { adaptee.jToggleButton1_actionPerformed(e); } }。
5.怎么用JAVA写一个用户登入程序
同意楼上的说法,具体点可以这样:创建一个用户表,里边包括LoginName(登录名),UserName(用户名),Password(密码),Age(年龄),Address(地址)。
然后编写Java程序(用MVC架构)模型层(M):DBConnection.java(负责连接数据库)import java.sql.Connection;import java.sql.DriverManager;import java.sql.*;public class DBConnection { private static final String DRIVER_CLASS = "sun.jdbc.odbc.JdbcOdbcDriver"; private static final String DB_URL = "jdbc:odbc:text"; public DBConnection() { } public static Connection getConnection() { Connection conn = null; try { Class.forName(DRIVER_CLASS); conn = DriverManager.getConnection(DB_URL); } catch (SQLException ex) { System.out.println(ex.getMessage()); } catch ( ex) { System.out.println(ex.getMessage()); } return conn; }}第2个负责数据库查询操作的类:DBUserManager.javaimport edu.systop.text.model.entity.User;import edu.systop.text.model.dao.DBConnection;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.DriverManager;import java.sql.*;public class DBUserManager { private static final String SQL_SELECT = "SELECT LoginName,UserName,PassWord,Age,Address FROM UserInfo WHERE LoginName = ? AND PassWord = ?"; public DBUserManager() { } public boolean checkDB(User u) { boolean b = false; Connection conn = null; PreparedStatement psmt = null; ResultSet rs = null; conn = DBConnection.getConnection(); try { psmt = conn.prepareStatement(SQL_SELECT); psmt.setString(1, u.getLoginName()); psmt.setString(2, u.getPassWord()); rs = psmt.executeQuery(); b = rs.next(); if (rs.next()) { b = true; } } catch (SQLException ex) { System.out.println(ex.getMessage()); } finally { cleanDB(rs, psmt, conn); } return b; } public User checkBC(User u) { Connection conn = null; PreparedStatement psmt = null; ResultSet rs = null; User tmp = new User(); conn = DBConnection.getConnection(); try { psmt = conn.prepareStatement(SQL_SELECT); psmt.setString(1, u.getLoginName()); psmt.setString(2, u.getPassWord()); rs = psmt.executeQuery(); if (rs.next()) { tmp.setLoginName(rs.getString(1)); tmp.setUserName(rs.getString(2)); tmp.setAge(rs.getInt(4)); tmp.setAddress(rs.getString(5)); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } finally { cleanDB(rs, psmt, conn); } return tmp; } public void cleanDB(ResultSet rs, PreparedStatement psmt, Connection conn) { try { if (rs != null) { rs.close(); } if (psmt != null) { psmt.close(); } if (conn != null) { conn.close(); } } catch (SQLException ex) { System.out.println(ex.getMessage()); } }第3个实体用户类:User.javapackage edu.systop.text.model.entity;public class User { private String loginName; private String userName; private String passWord; private int age; private String address; public User() { } public void setLoginName(String loginName) { this.loginName = loginName; } public void setUserName(String userName) { this.userName = userName; } public void setPassWord(String passWord) { this.passWord = passWord; } public void setAge(int age) { this.age = age; } public void setAddress(String address) { this.address = address; } public String getLoginName() { return loginName; } public String getUserName() { return userName; } public String getPassWord() { return passWord; } public int getAge() { return age; } public String getAddress() { return address; }}然后编写控制层(C):GetInfoServlet.javapackage edu.systop.text.control;import javax.servlet.*;import javax.servlet.; charset=gbk"; //Initialize global variables public void init() throws ServletException { } //Process the HTTP Get request public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { } //Process the HTTP Post request public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { String loginName = request.getParameter("loginName"); String passWord = request.getParameter("passWord"); User u = new User(); u.setLoginName(loginName); u.setPassWord(pa。
刚学时怎么写java代码
1.我是刚学java的,用什么写java代码比较好,不太想用记事本
MyEclipse,我们公司的java开发都用这个。。。
在配置EditPlus之前是先将JAVA的运行环境安装且调试好,然后进入EditPlus,从菜单“工具(Tools)”;“配置用户工具。”进入用户工具设置,选择“组和工具条目”中的“Group 1”,点击面板右边的“组名称。”按钮,将文本Group1”修改成“Java编译程序”,点击“添加工具”按钮,选择应用程序,然后就是修改属性:
1. 添加编译功能
“菜单文本”里的内容修改为“Javac”;
“命令”选择安装JDK后的Bin目录中的编译程序javac.exe,我的JDK 安装路径为“C:\Program Files\JDK\j2sdk1.4.2_08”,那么此路径为“C:\Program Files\JDK\j2sdk1.4.2_08\bin\javac.exe”;
“参数”选择“文件名”,即显示为“$(FileName)”;
“初始目录”选择“文件目录”,显示为“$(FileDir)”;选择“捕获输出”复选框
点击确定。
2. 添加执行功能
点击“添加工具”按钮,选择应用程序,然后就是修改属性:
“菜单文本”里的内容修改为“Java”;
“命令”选择安装JDK后的BIN目录中的编译程序java.exe,路径为“C:\Program
Files\JDK\j2sdk1.4.2_08\bin\javac.exe”;
“参数”选择“不带扩展名的文件名”,即显示为“$(FileNameNoExt)”;
“初始目录”选择“文件目录”,显示为“$(FileDir)”;选择“捕获输出”复选框,点击确定。
配置完成。
2.刚刚开始学习java 求助代码
public class ClassRoom{//教室
int desk;//桌子数量
int student;//学生数量
public void addDesk(int number){//添加桌子数量
desk+=number;
}
public void addStudent(int age){//添加学生,年龄限制
if(age<=30)student++;
}
}
由于你是初学java,我就尽量简化了,如果考虑多点的zhidao话,桌子学生都要设计成对象,并给予一定属性。采纳吧。可以追问。
3.我现在在学校刚开始学java,每次老师讲完后都懂,可是一到编写的时
学习Java开始时要多敲代码,做练习,前期可以直接根据书上的或老师给的代码重复多敲几次,在看着代码敲的过程中要学会去想,看代码中哪些语句是比较重要的,是否能用另一种表达式表示,不能急于求成,要尝试去修改书上或者老师给的代码,把他们的改成自己的,熟能生巧,有时候遇到不懂得要学会查API文档,学会上网找出解决的方法,如果自己不能单独解决,最好别把问题搁很久,问下同学或老师,用最快的方法去解决问题,理清思路,就像学数学一样,知道加减乘除如何运算,不管他的数据怎么变化,你都能解答出来,所以在听课的时候,你可能都能听懂,但缺乏练习,所以你只是似懂非懂。
如果你多练习,多总结的话,按自己的思路就能把代码敲出来了,还有一点就是在学习Java的时候,要理清代码中用了哪些类,哪些对象或那些包,这就要靠你平时多多琢磨了,还有什么问题可以随时问我咯。
4.java怎么编写
。.这个问题。。。太抽象了吧。。
总之java程序必须是由class组成的,每个class都可以有自己的main方法,每个文件里面最多有一个公有类,必须和文件名同名。
如HelloWorld.java:
//公有类
public class HelloWorld{
//main方法的固定写法,必须有String数组参数
public static void main(String args[]){
System.out.println("Hello World!");
}
}
刚开始学大致都会是像这样先建立一个public class,再在main方法里面写东西吧
java代码怎么写显示多个选择
1.在java中怎样实现多个界面之间的切换
一般在界面类中,因为界面类不是MIDlet的子类,所以需要获得Display对象有两个方法:
1、传递MIDlet类型的对象
2、传递Display类型的对象
下面就以传递Display对象为例来实现在界面类中进行切换。下面的程序为了简单起见,以两个Canvas界面为例来演示实际的传递,高级界面和这个使用完全一样。
MIDlet中的代码实现:
Display display;
public MyMIDlet(){
display = Display.getDisplay(this);
//创建需要显示的界面对象
FirstCanvas fc = new FirstCanvas(display);
//显示界面
display.setCurrent(fc);
}
第一个界面类的代码实现:
public class FirstCanvas extends Canvas{
Display display;
public FirstCanvas(Display display){
this.display = display;
}
/**绘制方法*/
public void paint(Graphics g){
g.drawString(“第一个界面”,30,40,Graphics.TOP | Graphics.LEFT);
}
/**事件处理*/
public void keyPressed(int keyCode){
display.setCurrent(new SecondCanvas(display)); //显示下一个界面
}
}
第二个界面类的代码实现和上一个类似:
Display display;
public SecondCanvas(Display display){
this.display = display;
}
上面的代码演示了如何使用传递Display对象的形式,在界面类中实现切换界面。当然除了该方式以外,需要实现该功能的方式还有很多种,这里只介绍这一种容易理解的实现方式。
2.java程序设计,求详解(最后几个字是:显示用户的选择)
第一步:写思路将全部数据储存到数组中或自定义数据类型或者集合中,因为数据初始化完毕后不会再涉及增删操作所以就用数组了,用户选定座位类型后遍历数组,如果座位可用则返回下标第二步:初始化数据Class xx {private int seats[] = new int[13][6];}//把所有座位都变成可用状态private void init(){for(int i = 0; i < seats.length; i++){for(int j = 0; i < seats[i].length; j++)seats[i][j] = 0; //0=可用}}}第三步:写取座位类型的方法public int getType(){System.out.println("请输入座位类型:1=头等舱,非1=经济舱");Scanner scan = new Scanner(System.in);return scan.nextInt() == 1 ? 1 : 0;}第四步:写分配座位方法public int getSeat(int seatType){for(int i = seatType == 1 ? 0 : 2 ; i < seatType == 1 ? 2 : seats.length; i++){for(int j = 0; i < seats[i].length; j++){if (seats[i][j] = 0)return i*6+j+1;}}}第五步:丢到main方法里public static void main(String[] arg0){System.err.println(getSeat(getType()));}以上代码没有在IDE中检测,直接在百度知道上一个字一个字打的,不保证没错,而且我是JAVA小白- -。
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