使用 Netbeans GUI 构建器，是否可能是同步、线程或按值/引用传递问题导致无法将 DefaultTableModel 从实用程序类传递到 JFrame？
两种情况下控制台输出都是相同的，代码只是从实用程序类复制/粘贴并放置在 JFrame 中。但是，如果使用实用程序类，则不会有 GUI 输出。
如何查明 JTable 为空或为空的原因？据我所知，DefaultTableModel 中填充了数据。
控制台输出:
init:
Deleting: /home/thufir/NetBeansProjects/SwingNNTP/build/built-jar.properties
deps-jar:
Updating property file: /home/thufir/NetBeansProjects/SwingNNTP/build/built-jar.properties
Compiling 1 source file to /home/thufir/NetBeansProjects/SwingNNTP/build/classes
warning: [options] bootstrap class path not set in conjunction with -source 1.5
1 warning
compile:
run:
Apr 23, 2012 9:46:25 PM net.bounceme.dur.nntp.EnumNNTP <init>
INFO: SingletonNNTP..only once...
Apr 23, 2012 9:46:25 PM net.bounceme.dur.nntp.PropertiesReader getProps
INFO: NNTP.loadMessages...
Apr 23, 2012 9:46:25 PM net.bounceme.dur.nntp.EnumNNTP connect
INFO: SingletonNNTP.connect..
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.EnumNNTP setIndex
INFO: SingletonNNTP.setIndex..164
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.EnumNNTP page
INFO: SingletonNNTP.page..174
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.EnumNNTP setIndex
INFO: SingletonNNTP.setIndex..164
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.EnumNNTP getMessages
INFO: SingletonNNTP.getMessages..
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="2f5f405c5b6f48584a414a01405d48" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="ea9a85999eaa8d9d8f848fc485988d" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="8dfde2fef9cdeafae8e3e8a3e2ffea" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="6b1b04181f2b0c1c0e050e4504190c" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="97e7f8e4e3d7f0e0f2f9f2b9f8e5f0" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="b5c5dac6c1f5d2c2d0dbd09bdac7d2" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="92e2fde1e6d2f5e5f7fcf7bcfde0f5" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="31415e4245715646545f541f5e4356" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="21514e5255614656444f440f4e5346" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="fc8c938f88bc9b8b999299d2938e9b" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:26 PM net.bounceme.dur.nntp.MessageBean setFrom
INFO: MessageBean.setFrom..unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="770718040337100012191259180510" rel="noreferrer noopener nofollow">[email protected]</a>>
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="92e2fde1e6d2f5e5f7fcf7bcfde0f5" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:24 PDT 2012The return of the euro crisis: Beyond battlefield medicine
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="5a2a35292e1a3d2d3f343f7435283d" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:24 PDT 2012North Korea’s gulag: Never again?
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="3848574b4c785f4f5d565d16574a5f" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:24 PDT 2012Nationalising YPF: Cristina scrapes the barrel
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="2858475b5c684f5f4d464d06475a4f" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:23 PDT 2012Charlemagne: April showers on the euro
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="5e2e312d2a1e39293b303b70312c39" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:23 PDT 2012Jihadist terrorism: Al-Qaeda is down, but far from out
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="6f1f001c1b2f08180a010a41001d08" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:23 PDT 2012Justice for dictators: History rules
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="562639252216312133383378392431" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:23 PDT 2012Buttonwood: Feeling peaky
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="43332c3037032434262d266d2c3124" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:23 PDT 2012Couples and housework: The ironing lady
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="1b6b74686f5b7c6c7e757e3574697c" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:23 PDT 2012Markets
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="1d6d726e695d7a6a78737833726f7a" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:22 PDT 2012The World Bank: Kim selection
Apr 23, 2012 9:46:27 PM net.bounceme.dur.nntp.MessageUtils getDataTableModel
INFO: unknown <<a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="30405f4344705747555e551e5f4257" rel="noreferrer noopener nofollow">[email protected]</a>>Sun Apr 22 02:58:22 PDT 2012The Economist commodity-price index
BUILD SUCCESSFUL (total time: 13 seconds)
MessagesJFrame 中注释掉的代码实际上可以工作，但将其传递给实用程序类会带来问题 - 显然是空的 JTable。
JFrame:
package net.bounceme.dur.nntp;
import java.util.List;
import java.util.Vector;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.mail.Message;
import javax.swing.table.DefaultTableModel;
public class MessagesJFrame extends javax.swing.JFrame {
private DefaultTableModel defaultTableModel = new DefaultTableModel();
public MessagesJFrame() throws Exception {
initComponents();
MessageUtils.loadMessages();
defaultTableModel = MessageUtils.getDataTableModel();
/*
EnumNNTP nntp = EnumNNTP.INSTANCE;
List<Message> listOfMessages = nntp.getMessages(false);//nntp debug off
Vector messages = new Vector();
for (Message m : listOfMessages) {
MessageBean messageBean = new MessageBean(m);
messages.add(messageBean);
}
defaultTableModel.addColumn("from");
defaultTableModel.addColumn("sent");
defaultTableModel.addColumn("subject");
for (Object o : messages) { //awkward Vector manipulation
MessageBean messageBean = (MessageBean) o;
Vector messageBeanAsVector = messageBean.getVector();
defaultTableModel.addRow(messageBeanAsVector);
}*/
}
/**
* 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() {
jScrollPane1 = new javax.swing.JScrollPane();
jTable1 = new javax.swing.JTable();
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
jTable1.setModel(defaultTableModel);
jScrollPane1.setViewportView(jTable1);
javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
getContentPane().setLayout(layout);
layout.setHorizontalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 819, Short.MAX_VALUE)
.addContainerGap())
);
layout.setVerticalGroup(
layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(layout.createSequentialGroup()
.addContainerGap()
.addComponent(jScrollPane1, javax.swing.GroupLayout.DEFAULT_SIZE, 455, Short.MAX_VALUE)
.addContainerGap())
);
pack();
}// </editor-fold>
/**
* @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(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(MessagesJFrame.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(MessagesJFrame.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() {
try {
new MessagesJFrame().setVisible(true);
} catch (Exception ex) {
Logger.getLogger(MessagesJFrame.class.getName()).log(Level.SEVERE, null, ex);
}
}
});
}
// Variables declaration - do not modify
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTable jTable1;
// End of variables declaration
}
实用类:
package net.bounceme.dur.nntp;
import java.util.Iterator;
import java.util.List;
import java.util.Vector;
import java.util.logging.Logger;
import javax.mail.Message;
import javax.swing.table.DefaultTableModel;
public class MessageUtils {
private static final long serialVersionUID = 1L;
private static final Logger LOG = Logger.getLogger(MessageUtils.class.getName());
private static DefaultTableModel defaultTableModel = new DefaultTableModel();
private static EnumNNTP nntp = EnumNNTP.INSTANCE;
private static Vector messages = new Vector();
public static void loadMessages() throws Exception {
List<Message> listOfMessages = nntp.getMessages(false);//nntp debug off
messages.clear();
for (Message m : listOfMessages) {
MessageBean messageBean = new MessageBean(m);
messages.add(messageBean);
}
loadTableModel();
}
private static void loadTableModel() {
defaultTableModel = new DefaultTableModel();
defaultTableModel.addColumn("from");
defaultTableModel.addColumn("sent");
defaultTableModel.addColumn("subject");
for (Object o : messages) { //awkward Vector manipulation
MessageBean messageBean = (MessageBean) o;
Vector messageBeanAsVector = messageBean.getVector();
defaultTableModel.addRow(messageBeanAsVector);
}
}
public static DefaultTableModel getDataTableModel() {
Vector vector = defaultTableModel.getDataVector();
Iterator it = vector.iterator();
while (it.hasNext()) {
Vector v = (Vector) it.next();
Iterator i = v.iterator();
StringBuilder row = new StringBuilder();
while (i.hasNext()) {
row.append(i.next());
}
LOG.info(row.toString());
}
return defaultTableModel;
}
public static void setDataTableModel(DefaultTableModel dataTableModel) {
MessageUtils.defaultTableModel = dataTableModel;
}
public static Vector getMessages() {
return messages;
}
public static void setMessages(Vector messages) {
MessageUtils.messages = messages;
}
}
最佳答案
当然，您最终会得到一个空的JTable。您有两个名为 defaultTableModel 的实例，它们没有任何共同点。您需要将您在 UI 中使用的 defaultTableModel 传递给实用程序类，并让实用程序类填充该特定模型(或者相反，设置 defaultTableModel在实用程序类中用作 JTable 模型的实例。
编辑
需要明确的是，问题在于您可能认为
defaultTableModel = MessageUtils.getDataTableModel();
将调整您在 JTable 上设置的模型，但事实并非如此。它只是使您的 defaultTableModel 字段引用另一个 TableModel，然后引用原始的。如果您只是将此行移动到构造函数的第一行，您的代码将起作用，因为您实际上将 MessageUtils.getDataTableModel() 的结果设置为 TableModel你的JTable
关于java - JTable 在 GUI 中为空，控制台显示已填充的 DefaultTableModel，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10291908/