ObservableList <Message>到TableView
希望我会尽可能清楚地说明我的问题。 我正在使用gui的JavaFX库开发一个小型的Java应用程序。 我正在做一个POP连接并将消息存储为ObservableList。 为此，我使用javax.mail。 我将这个可观察列表传递给tableview，并将下面的代码传递给TableColumns：
fromColumn.setCellValueFactory(
new PropertyValueFactory<Message,String>("from")
);
subjectColumn.setCellValueFactory(
new PropertyValueFactory<Message,String>("subject")
);
dateColumn.setCellValueFactory(
new PropertyValueFactory<Message,String>("sentDate")
);
主题和发送日期正在完美地读入。 但不幸的是，“from”是将对象引用添加到TableColumn，因为Message-Class中的From-Attribute是InternetAdress-Object，它的toString（） - 方法不返回字符串，但可能是引用。 结果是从列中显示的结果：
[Ljavax.mail.internet.InternetAddress;@3596cd38
任何人都知道解决方案如何获得所提到的列中显示的InternetAdress的字符串值？
提前致谢
我认为你需要定义一个自定义的单元格值工厂来获取所需格式的地址信息，而不是使用PropertyValueFactory。
以下示例适用于只读表 - 如果表中的消息数据需要可编辑，那么解决方案将显得更加复杂。
fromColumn.setCellValueFactory(new Callback<CellDataFeatures<Message, String>, ObservableValue<String>>() {
@Override public ObservableValue<String> call(CellDataFeatures<Message, String> m) {
// m.getValue() returns the Message instance for a particular TableView row
return new ReadOnlyObjectWrapper<String>(Arrays.toString(m.getValue().getFrom()));
}
});
下面是一个可执行示例（加上示例数据文件），演示了自定义单元格值工厂的使用。 将示例数据文件放在与应用程序java程序相同的目录中，并确保构建系统将示例文件复制到构建输出目录，该目录包含应用程序的已编译类文件。 您将需要路径上的javamail jar文件来编译和运行应用程序。
import java.io.*;
import java.util.Arrays;
import java.util.logging.*;
import javafx.application.Application;
import javafx.beans.property.ReadOnlyObjectWrapper;
import javafx.beans.value.ObservableValue;
import javafx.collections.*;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.control.TableColumn.CellDataFeatures;
import javafx.scene.control.cell.PropertyValueFactory;
import javafx.scene.layout.VBox;
import javafx.scene.text.Font;
import javafx.stage.Stage;
import javafx.util.Callback;
import javax.mail.*;
import javax.mail.internet.MimeMessage;
public class MailTableSample extends Application {
private TableView<Message> table = new TableView<Message>();
public static void main(String[] args) { launch(args);}
@Override public void start(Stage stage) {
stage.setTitle("Table View Sample");
final Label label = new Label("Mail");
label.setFont(new Font("Arial", 20));
table.setEditable(false);
TableColumn subjectColumn = new TableColumn("Subject");
subjectColumn.setMinWidth(100);
subjectColumn.setCellValueFactory(
new PropertyValueFactory<Message, String>("subject")
);
TableColumn sentDate = new TableColumn("Sent");
sentDate.setMinWidth(100);
sentDate.setCellValueFactory(
new PropertyValueFactory<Message, String>("sentDate")
);
TableColumn fromColumn = new TableColumn("From");
fromColumn.setMinWidth(200);
fromColumn.setCellValueFactory(new Callback<CellDataFeatures<Message, String>, ObservableValue<String>>() {
@Override public ObservableValue<String> call(CellDataFeatures<Message, String> m) {
try {
// m.getValue() returns the Message instance for a particular TableView row
return new ReadOnlyObjectWrapper<String>(Arrays.toString(m.getValue().getFrom()));
} catch (MessagingException ex) {
Logger.getLogger(MailTableSample.class.getName()).log(Level.SEVERE, null, ex);
return null;
}
}
});
table.setItems(fetchMessages());
table.getColumns().addAll(fromColumn, subjectColumn, sentDate);
table.setPrefSize(600, 200);
final VBox vbox = new VBox();
vbox.setSpacing(5);
vbox.setPadding(new Insets(10));
vbox.getChildren().addAll(label, table);
stage.setScene(new Scene(vbox));
stage.show();
}
private ObservableList<Message> fetchMessages() {
ObservableList<Message> messages = FXCollections.observableArrayList();
try {
Session session = Session.getDefaultInstance(System.getProperties());
for (int i = 0; i < 3; i++) {
InputStream mboxStream = new BufferedInputStream(
getClass().getResourceAsStream("msg_" + (i+1) + ".txt")
);
Message message = new MimeMessage(session, mboxStream);
messages.add(message);
}
} catch (MessagingException ex) {
Logger.getLogger(MailTableSample.class.getName()).log(Level.SEVERE, null, ex);
}
return messages;
}
}
msg_1.txt
From cras@irccrew.org Tue Jul 23 19:39:23 2002
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Date: Tue, 23 Jul 2002 19:39:23 +0300
From: Timo Sirainen <tss@iki.fi>
To: dovecot@procontrol.fi
Subject: [dovecot] first test mail
Message-ID: <20020723193923.J22431@irccrew.org>
Mime-Version: 1.0
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Status: O
lets see if it works
msg_2.txt
From cras@irccrew.org Mon Jul 29 02:17:12 2002
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Date: Mon, 29 Jul 2002 02:17:11 +0300
From: John Smith <jsmithspam@yahoo.com>
To: dovecot@procontrol.fi
Subject: [dovecot] Dovecot 0.93 released
Message-ID: <20020729021711.W22431@irccrew.org>
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Status: O
First alpha quality release, everything critical is now implemented. From
now on it's mostly stabilization and optimization. Features that can't break
existing code could still be added, especially SSL and authentication stuff.
msg_3.txt
From cras@irccrew.org Wed Jul 31 22:48:41 2002
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Date: Wed, 31 Jul 2002 22:48:39 +0300
From: Timo Sirainen <tss@iki.fi>
To: dovecot@procontrol.fi
Subject: [dovecot] v0.95 released
Message-ID: <20020731224839.H22431@irccrew.org>
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Status: O
v0.95 2002-07-31 Timo Sirainen <tss@iki.fi>
+ Initial SSL support using GNU TLS, tested with v0.5.1.
TLS support is still missing.
+ Digest-MD5 authentication method
+ passwd-file authentication backend
+ Code cleanups
- Found several bugs from mempool and ioloop code, now we should
be stable? :)
- A few corrections for long header field handling
示例程序输出： 
使用上面提到的解决方案，我使用它，或者我接受Eclipse的建议，我添加一个try / catch和另一个返回值，最后看起来像这样：
fromColumn.setCellValueFactory(new Callback<CellDataFeatures<Message, String>, ObservableValue<String>>() {
public ObservableValue<String> call(CellDataFeatures<Message, String> m) {
// m.getValue() returns the Message instance for a particular TableView row
try {
return new ReadOnlyObjectWrapper<String>(Arrays.toString(m.getValue().getFrom()));
} catch (MessagingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
});
结果是一样的，我得到一个（视觉）空的tableview。 这意味着即使是使用setCellFactury（）解决方案的表列也是空的。 那么，作为解决方法，我可以定义一个类，我可以将三个值存储为一个字符串，然后使用PropertyValueFactory将其传递给setCellValueFactory（），但我希望能够正确完成它。
还有什么建议？
最好的祝福
这是一个Java 8版本的jewelsea解决方案，但在真棒lambdas：
fromColumn.setCellValueFactory(m -> {
// m.getValue() returns the Message instance for a particular TableView row
return new ReadOnlyObjectWrapper<String>(Arrays.toString(m.getValue().getFrom()));
}
});
哈哈，得爱拉姆达斯
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