我的应用程序下面有Loginscreen; （我使用netbeans gui designer）
public class loginscreen extends javax.swing.JFrame {
/**
* Creates new form loginscreen
*/
public loginscreen() {
initComponents();
}
/**
* This method is called from within the constructor to initialize the form.
* WARNING: Do NOT modify this code. The content of this method is always
* regenerated by the Form Editor.
*/
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {
Uname_Textfield = new javax.swing.JTextField();
Password_PasswordField = new javax.swing.JPasswordField();
Bağlan_Buton = new javax.swing.JButton();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setResizable(false);
Uname_Textfield.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
Uname_TextfieldActionPerformed(evt);
}
});
Bağlan_Buton.setText("Bağlan");
Bağlan_Buton.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
Bağlan_ButonActionPerformed(evt);
}
});
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(10, 10, 10)
.addComponent(Uname_Textfield, javax.swing.GroupLayout.PREFERRED_SIZE, 150, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGap(10, 10, 10)
.addComponent(Password_PasswordField, javax.swing.GroupLayout.PREFERRED_SIZE, 150, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGroup(layout.createSequentialGroup()
.addGap(54, 54, 54)
.addComponent(Bağlan_Buton)))
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addGap(11, 11, 11)
.addComponent(Uname_Textfield, javax.swing.GroupLayout.PREFERRED_SIZE, 31, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(18, 18, 18)
.addComponent(Password_PasswordField, javax.swing.GroupLayout.PREFERRED_SIZE, 30, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(Bağlan_Buton, javax.swing.GroupLayout.PREFERRED_SIZE, 31, javax.swing.GroupLayout.PREFERRED_SIZE)
.addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
);
pack();
setLocationRelativeTo(null);
}// </editor-fold>
private void Uname_TextfieldActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
}
private void Bağlan_ButonActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
String user=Uname_Textfield.getText();
String pwd= new String (Password_PasswordField.getPassword());
try {
Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
String connectionUrl = "jdbc:sqlserver://192.168.131.10;" + "databaseName=ExampleDB;" + "user=" + user + ";" + "password=" + pwd + ";";
Connection con = DriverManager.getConnection(connectionUrl);
new ProgramPenceresi().setVisible(true);
dispose();
}
catch (SQLException e) {
JOptionPane.showMessageDialog(this, "Kullanıcı Adı veya Şifre Yanlış!");
}
catch (ClassNotFoundException cE) {
System.out.println("Class Not Found Exception: "+ cE.toString());
}
}
/**
* @param args the command line arguments
*/
public static void main(String args[]) {
/* Set the Nimbus look and feel */
//<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
/* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
* For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html
*/
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(loginscreen.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(loginscreen.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(loginscreen.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(loginscreen.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
}
//</editor-fold>
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
new loginscreen().setVisible(true);
}
});
}
// Variables declaration - do not modify
private javax.swing.JButton Bağlan_Buton;
private javax.swing.JPasswordField Password_PasswordField;
private javax.swing.JTextField Uname_Textfield;
// End of variables declaration
}
我使用此loginscreen来识别数据库中的用户。我有另一个SQLSP类用于在DB中执行存储过程。
如果用户使用真实登录详细信息成功登录系统，则会在屏幕上显示另一个java框架。当用户与此屏幕交互并从SQLSP类调用某些sqlsp时，我必须使用uname＆amp; amp;登录到db。 loginscreen.java中的密码
但是uname和密码存储在
中privatevoidBağlan_ButonActionPerformed（java.awt.event.ActionEvent evt）
下的
public class loginscreen扩展了javax.swing.JFrame
如何从另一个类访问用户和pwd变量？
我试试
loginscreen logindetails = new loginscreen();
String username = logindetails.user;
但没有帮助。我怎样才能访问它们？
答案 0 :(得分：4)
user是您班级方法中的局部变量。在声明它们的方法之外的任何地方都无法访问局部变量。
你真正想做的是在类中声明一个类变量：
private String username;
然后为此变量提供公共getter：
public String getUsername()
{
return username;
}
然后在适当的地方在课堂内设置username。您班外的代码可以使用logindetails.getUsername()来访问存储的用户名。
答案 1 :(得分：2)
您可以使用多种可能性......
使用某种getter从登录类返回用户。的。您只需要以某种方式存储该值，然后将其传递给程序的其他部分
一般来说，我倾向于选择这个选项，但这可能意味着你最终将几十个参数传递给并不真正需要它们的类，因为它们有一个需要它的类或子类......
使用单例存储活动用户，因此当用户首次登录时，您将设置单例的值，以便程序的其他部分可以在需要时从单例中获取它。
如果您打算仅允许单个用户访问单个数据库，那么这很好。如果您需要支持多个数据库或用户，第一个选项将成为您唯一的选择