我正在学习java，我有一个小问题， 我试图从 Jtextfield 获取“文本”，但它发送为空。 更具体地说。
我有一个 JFrame，其中有界面和 JTextfield，还有一个名为“保存”的按钮，当我按下保存时，它会打开一个包含操作的类(写入属性文件)，问题是当我尝试要直接从此类中从文本字段获取文本，我得到“无 - 空”我尝试 System.out.print();但我什么也得不到...如果我用variable.getText();从JFrame打印它得到正确的，我尝试使用 getter 和 setter，并尝试直接从变量获取，例如:
JFrame obj = new JFrame();
String variable = obj.txt_jtextfield.getText();
没有成功，这基本上是代码:
按钮:
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
db_connection_modifier obj = new db_connection_modifier();
obj.hostconfig();
//System.out.println("Conexion: "+txt_ip.getText()+"\n"+txt_db.getText()+"\n"+txt_user.getText()+"\n"+txt_pass.getText());
}
方法是这样的:
public void hostconfig(){
dbconfig_manager obj1 = new dbconfig_manager();
String ip = obj1.txt_ip.getText();
String db_name = obj1.txt_db.getText();
String user = obj1.txt_user.getText();
String password = obj1.txt_pass.getText();
System.out.println("DATA: " + dbconfig_manager.txt_ip.getText() + "\n" +dbconfig_manager.txt_db.getText() + "\n" + user + "\n" + password);
}
我得到了空，我不知道是不是因为“Button”的原因，我不太了解“new”命令
提前致谢:)
编辑:
这是完整的类:
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package clases;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Properties;
import interfaz.*;
import java.io.FileInputStream;
import java.util.Enumeration;
/**
*
* @author TheCoder
*/
public class db_connection_modifier {
public void hostconfig() {
Properties prop = new Properties();
dbconfig_manager obj1 = new dbconfig_manager();
String ip = obj1.txt_ip.getText();
String db_name = obj1.txt_db.getText();
String user = obj1.txt_user.getText();
String password = obj1.txt_pass.getText();
System.out.println("INFO: " + dbconfig_manager.txt_ip.getText() + "\n" + dbconfig_manager.txt_db.getText() + "\n" + user + "\n" + password);
FileInputStream is = null;
// Cargamos el fichero de propiedades
try {
// Asumimos que el fichero existe
String path = getClass().getResource("db_config.properties").getPath();
//CARGAMOS EL ARCHIVO
prop.load(new FileInputStream(path));
} catch (IOException ioe) {
ioe.printStackTrace();
}
// Listamos las propiedades
System.out.println("PROPIEDADES POR DEFECTO");
for (Enumeration e = prop.keys(); e.hasMoreElements();) {
Object obj = e.nextElement();
System.out.println(obj + ": "
+ prop.getProperty(obj.toString()));
}
// Modificamos los valores
prop.setProperty("db_ip", obj1.txt_ip.getText());
prop.setProperty("db_name", obj1.txt_db.getText());
prop.setProperty("Login_type", "");
prop.setProperty("db_username", obj1.db_name);
prop.setProperty("db_password", obj1.password);
// Volvemos a listar los valores
System.out.println("PROPIEDADES MODIFICADAS");
for (Enumeration e = prop.keys(); e.hasMoreElements();) {
Object obj = e.nextElement();
System.out.println(obj + ": "
+ prop.getProperty(obj.toString()));
}
// try {
//
// Properties prop = new Properties();
// dbconfig_manager obj = new dbconfig_manager();
// String ip = obj.txt_ip.getText();
// String db_name = obj.txt_db.getText();
// String user = obj.txt_user.getText();
// String password = obj.txt_pass.getText();
//
// System.out.println("Conexion: "+ip+"\n"+db_name+"\n"+user+"\n"+password);
//
// prop.setProperty("db_ip", ip);
// prop.setProperty("db_name", db_name);
//
// if (obj.cb_method.getSelectedIndex() == 0) {
// prop.setProperty("Login_Type", "win_auth");
//
// } else if (obj.cb_method.getSelectedIndex() == 1) {
// prop.setProperty("Login_Type", "manual_auth");
// prop.setProperty("db_username", user);
// prop.setProperty("db_password", password);
//
// System.out.println("Paso por aqui!!!");
//
// }
//
//
// //save properties to project root folder
// String path = getClass().getResource("DB_configuration.properties").getPath();
// prop.store(new FileOutputStream(path), null);
//
// } catch (IOException ex) {
// System.out.println(ex);
// }
}
}
这是 JFrame:
/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package interfaz;
import clases.*;
import javax.swing.JComboBox;
import javax.swing.JPasswordField;
import javax.swing.JTextField;
/**
*
* @author TheCoder
*/
public class dbconfig_manager extends javax.swing.JFrame {
/**
* Creates new form dbconfig_manager
*/
public dbconfig_manager() {
initComponents();
// mauth_panel.setVisible(false);
}
/**
* 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() {
jPanel1 = new javax.swing.JPanel();
jLabel2 = new javax.swing.JLabel();
jLabel3 = new javax.swing.JLabel();
jLabel4 = new javax.swing.JLabel();
mauth_panel = new javax.swing.JPanel();
jLabel5 = new javax.swing.JLabel();
jLabel6 = new javax.swing.JLabel();
txt_user = new javax.swing.JTextField();
txt_pass = new javax.swing.JPasswordField();
jButton1 = new javax.swing.JButton();
jButton2 = new javax.swing.JButton();
cb_method = new javax.swing.JComboBox();
txt_ip = new javax.swing.JTextField();
txt_db = new javax.swing.JTextField();
jButton3 = new javax.swing.JButton();
jLabel1 = new javax.swing.JLabel();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
setPreferredSize(new java.awt.Dimension(1024, 768));
getContentPane().setLayout(null);
jPanel1.setBackground(java.awt.Color.lightGray);
jPanel1.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED));
jPanel1.setOpaque(false);
jLabel2.setBackground(new java.awt.Color(255, 255, 255));
jLabel2.setFont(new java.awt.Font("Lucida Sans", 1, 11)); // NOI18N
jLabel2.setForeground(new java.awt.Color(255, 255, 255));
jLabel2.setText("Domain name(IP): ");
jLabel3.setBackground(new java.awt.Color(255, 255, 255));
jLabel3.setFont(new java.awt.Font("Lucida Sans", 1, 11)); // NOI18N
jLabel3.setForeground(new java.awt.Color(255, 255, 255));
jLabel3.setText("Data base name: ");
jLabel4.setBackground(new java.awt.Color(255, 255, 255));
jLabel4.setFont(new java.awt.Font("Lucida Sans", 1, 11)); // NOI18N
jLabel4.setForeground(new java.awt.Color(255, 255, 255));
jLabel4.setText("Method: ");
jLabel5.setText("Usuario: ");
jLabel6.setText("Contraseña: ");
javax.swing.GroupLayout mauth_panelLayout = new javax.swing.GroupLayout(mauth_panel);
mauth_panel.setLayout(mauth_panelLayout);
mauth_panelLayout.setHorizontalGroup(
mauth_panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(mauth_panelLayout.createSequentialGroup()
.addGap(35, 35, 35)
.addGroup(mauth_panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel5)
.addComponent(jLabel6))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addGroup(mauth_panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(txt_user)
.addComponent(txt_pass, javax.swing.GroupLayout.DEFAULT_SIZE, 222, Short.MAX_VALUE))
.addContainerGap(49, Short.MAX_VALUE))
);
mauth_panelLayout.setVerticalGroup(
mauth_panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(mauth_panelLayout.createSequentialGroup()
.addGap(19, 19, 19)
.addGroup(mauth_panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel5)
.addComponent(txt_user, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(mauth_panelLayout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel6)
.addComponent(txt_pass, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addContainerGap(58, Short.MAX_VALUE))
);
jButton1.setText("Guardar");
jButton1.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton1ActionPerformed(evt);
}
});
jButton2.setText("Borrar");
cb_method.setModel(new javax.swing.DefaultComboBoxModel(new String[] { "win_auth", "manual_auth" }));
cb_method.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
cb_methodActionPerformed(evt);
}
});
jButton3.setText("jButton3");
jButton3.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
jButton3ActionPerformed(evt);
}
});
javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
jPanel1.setLayout(jPanel1Layout);
jPanel1Layout.setHorizontalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(23, 23, 23)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(mauth_panel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING, false)
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, jPanel1Layout.createSequentialGroup()
.addComponent(jLabel2)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
.addComponent(txt_ip))
.addGroup(javax.swing.GroupLayout.Alignment.LEADING, jPanel1Layout.createSequentialGroup()
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addComponent(jLabel3)
.addComponent(jLabel4))
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
.addComponent(cb_method, 0, 200, Short.MAX_VALUE)
.addComponent(txt_db)))))
.addContainerGap(50, Short.MAX_VALUE))
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
.addGap(45, 45, 45)
.addComponent(jButton3)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
.addComponent(jButton1)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.UNRELATED)
.addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 83, javax.swing.GroupLayout.PREFERRED_SIZE)
.addGap(77, 77, 77))
);
jPanel1Layout.setVerticalGroup(
jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel1Layout.createSequentialGroup()
.addGap(14, 14, 14)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel2)
.addComponent(txt_ip, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel3)
.addComponent(txt_db, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(18, 18, 18)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jLabel4)
.addComponent(cb_method, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
.addGap(46, 46, 46)
.addComponent(mauth_panel, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
.addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 47, Short.MAX_VALUE)
.addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jButton1)
.addComponent(jButton2)
.addComponent(jButton3))
.addGap(25, 25, 25))
);
getContentPane().add(jPanel1);
jPanel1.setBounds(300, 110, 450, 390);
jLabel1.setIcon(new javax.swing.ImageIcon(getClass().getResource("/imagenes/stretched-38776.jpg"))); // NOI18N
getContentPane().add(jLabel1);
jLabel1.setBounds(0, 0, 1024, 768);
pack();
}// </editor-fold>
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
db_connection_modifier obj = new db_connection_modifier();
obj.hostconfig();
//System.out.println("Conexion: "+txt_ip.getText()+"\n"+txt_db.getText()+"\n"+txt_user.getText()+"\n"+txt_pass.getText());
}
private void cb_methodActionPerformed(java.awt.event.ActionEvent evt) {
if (cb_method.getSelectedIndex() == 0) {
System.out.println("win_auth: " + cb_method.getSelectedIndex());
mauth_panel.setVisible(false);
} else if (cb_method.getSelectedIndex() == 1) {
System.out.println("manual_auth: " + cb_method.getSelectedIndex());
mauth_panel.setVisible(true);
}
}
private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {
System.out.println("Obteniendo datos: " + txt_ip.getText() + "\n" + txt_db.getText()
+ "\n" + txt_user.getText() + "\n" + txt_pass.getText());
}
/**
* @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(dbconfig_manager.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(dbconfig_manager.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(dbconfig_manager.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(dbconfig_manager.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 dbconfig_manager().setVisible(true);
}
});
}
// Variables declaration - do not modify
public javax.swing.JComboBox cb_method;
private javax.swing.JButton jButton1;
private javax.swing.JButton jButton2;
private javax.swing.JButton jButton3;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JLabel jLabel5;
private javax.swing.JLabel jLabel6;
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel mauth_panel;
public static javax.swing.JTextField txt_db;
public static javax.swing.JTextField txt_ip;
public static javax.swing.JPasswordField txt_pass;
public static javax.swing.JTextField txt_user;
// End of variables declaration
}
正如我之前所说...当我尝试时，我只是变得“空”:
System.out.println("INFO: " + ip + "\n" + db_name + "\n" + user + "\n" + password);
最佳答案
因此 JFrame 没有名为 txt_jtextfield 的方法或属性
不知道如何实际构建此 JFrame，因此很难知道该建议什么。
假设你做了类似的事情......
JText txt_jtextfield = new JTextField();
JFrame obj = new JFrame();
// Some other initialisation code...
obj.add(txt_jtextfield);
您应该能够直接获取该值。
如果该字段位于它“自己的”框架中。您应该直接创建父框架
FrameWithTextFieldInIt obj = new FrameWithTextFieldInIt();
// etc...
然后由框架来提供对该字段的访问(通过将其公开，或者更好地通过 getter)
您确实需要提供有关文本字段存在位置以及您尝试访问它的上下文的更多信息
已更新
您不能以这种方式使用 JFrame。
dbconfig_manager obj1 = new dbconfig_manager();
String ip = obj1.txt_ip.getText();
基本上是在说，“给我一个框架，完成后继续运行”。这意味着文本字段中没有任何内容。
两个选项。
- 改用模态
JDialog，请参阅 How to make Dialogs - 改变您的工作流程。
不要让db_connection_modifier类负责显示UI，而是让它只负责更新属性并使用某种“更新”按钮创建配置框架，该按钮将调用db_connection_modifier 类
更新
Max 也是正确的，在您是“Guardar”按钮的操作处理程序中，您正在执行此操作...
db_connection_modifier obj = new db_connection_modifier();
obj.hostconfig();
这正在创建一个全新的dbconfig_manager，其中没有详细信息。您应该直接将属性传递给它...
db_connection_modifier obj = new db_connection_modifier(txt_ip.getText(), txt_db.getText(), txt_user.getText(), txt_pass.getText());
obj.hostconfig();
这会将您的 UI 与应用程序逻辑分离
关于java - 如何从 JFrame 获取文本，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/11998722/