1

我正在学习 java 并且有一个小问题，我试图从 Jtextfield 获取“文本”，但它发送的是空的。更具体。

我有一个 JFrame，其中接口和 JTextfield 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），问题是当我尝试获取直接来自此类的文本字段中的文本我得到“无 - 空”我试图 System.out.print(); 但我什么也没得到……如果我用 variable.getText() 从 JFrame 打印；它得到了正确的，我尝试使用 getter 和 setter 并尝试直接从变量中获取，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());
}

这是方法：

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);
}

我空了，我不知道是不是因为“按钮”，我对“新”命令不太了解

提前致谢 ：）

编辑：

这是完整的课程：

/*
 * 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“空虚”：

    System.out.println("INFO:  " + ip + "\n" + db_name + "\n" + user + "\n" + password);
4

2 回答 2

4

所以JFrame没有调用的方法或属性txt_jtextfield

不知道您是如何实际构建JFrame的，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。

如果该字段存在于它的“自己的”框架中。您应该直接创建父框架

FrameWithTextFieldInIt obj = new FrameWithTextFieldInIt();
// etc...

然后由框架提供对该字段的访问（通过将其公开，或者更优选地，通过吸气剂）

您确实需要提供有关文本字段存在位置以及尝试访问它的上下文的更多信息

更新

您不能JFrame以这种方式使用 a 。

dbconfig_manager obj1 = new dbconfig_manager();
String ip = obj1.txt_ip.getText();

基本上是在说，“给我做一个框架，完成后继续运行”。这意味着，文本字段中没有任何内容。

两种选择。

  1. 改为使用模式JDialog，请参阅如何制作对话框
  2. 改变你的工作流程。

而不是db_connection_modifier类负责显示 UI，使其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该类

更新

Max 也是正确的，在你是“Guardar”按钮的动作处理程序中，你正在这样做......

db_connection_modifier obj = new db_connection_modifier();
obj.hostconfig();

这正在创建一个全新的dbconfig_manager，其中没有任何细节。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();

这将使您的 UI 与您的应用程序逻辑分离

于 2012-08-17T02:05:19.523 回答
3

看起来像db_connection_modifier创建新实例dbconfig_manager而不是使用现有框架。要解决问题，请将现有框架的实例传递给dbconfig_manager. 最好将连接参数包装到一个类中，然后传递这个类。

于 2012-08-17T02:29:57.897 回答