如何使用FileeChooser在javaFX中创建新文件并将数据保存在文件中？
如何使用FileeChooser在javaFX中创建新文件并将数据保存在文件中？
提问于 2020-05-26 12:57:18
我需要通过对话框保存文件。对话框打开，但文件本身未保存，如何修复？代码：
FileChooser fileChooser = new FileChooser();
fileChooser.setTitle("Save");
fileChooser.setInitialFileName("save file");
fileChooser.getExtensionFilters().addAll(new FileChooser.ExtensionFilter("All Files", "*.*"));
//Adding action on the menu item
save.setOnAction(new EventHandler<ActionEvent>() {
public void handle(ActionEvent event) {
//Opening a dialog box
fileChooser.getExtensionFilters()
.addAll(
new FileChooser.ExtensionFilter("TXT files (*.TXT)", "*.TXT"),
new FileChooser.ExtensionFilter("txt files (*.txt)", "*.txt")
);
fileChooser.showSaveDialog(primaryStage);
}
});回答 3
Stack Overflow用户
回答已采纳
发布于 2020-05-26 15:18:15
下面是一个小示例，如果您希望创建一个具有特定文件名(TextField)、文件扩展名(ComboBox)和目标目录(DirectoryChooser)的新文件：
控制员类别：
package sample;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.ComboBox;
import javafx.scene.control.TextField;
import javafx.stage.DirectoryChooser;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.ResourceBundle;
public class Controller implements Initializable {
@FXML
private Button
saveBtn;
@FXML
private TextField
fileNameTextField,
directoryTextField;
@FXML
private ComboBox<String>
fileExtensionComboBox;
@Override
public void initialize(URL location, ResourceBundle resources) {
fileExtensionComboBox.getItems().addAll(".txt", ".json", ".xml");
saveBtn.disableProperty().bind(fileNameTextField.textProperty().isEmpty()
.or(fileExtensionComboBox.getSelectionModel().selectedItemProperty().isNull()
.or(directoryTextField.textProperty().isEmpty())));
}
@FXML
public void handleChangeDirectoryBtnClick() {
DirectoryChooser directoryChooser = new DirectoryChooser();
File selectedDirectory = directoryChooser.showDialog(null);
if (selectedDirectory != null) directoryTextField.setText(selectedDirectory.getAbsolutePath());
}
@FXML
public void handleSaveBtnClick() {
Path file = Paths.get(directoryTextField.getText(), fileNameTextField.getText().trim() + fileExtensionComboBox.getSelectionModel().getSelectedItem());
if(!Files.exists(file)) { {
try {
Files.createFile(file.toAbsolutePath());
//...
} catch (IOException e) {
e.printStackTrace();
}
}
}
}FXML文件：
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.ComboBox?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.RowConstraints?>
<GridPane hgap="3.0" vgap="3.0" xmlns="http://javafx.com/javafx/11.0.1" xmlns:fx="http://javafx.com/fxml/1" fx:controller="sample.Controller">
<columnConstraints>
<ColumnConstraints hgrow="SOMETIMES" />
<ColumnConstraints hgrow="SOMETIMES" />
</columnConstraints>
<rowConstraints>
<RowConstraints vgrow="SOMETIMES" />
<RowConstraints vgrow="SOMETIMES" />
<RowConstraints vgrow="SOMETIMES" />
<RowConstraints vgrow="SOMETIMES" />
<RowConstraints vgrow="SOMETIMES" />
</rowConstraints>
<children>
<Label text="File Name:" />
<TextField fx:id="fileNameTextField" GridPane.rowIndex="1" />
<Label text="File Extension:" GridPane.columnIndex="1" />
<ComboBox fx:id="fileExtensionComboBox" prefWidth="150.0" GridPane.columnIndex="1" GridPane.rowIndex="1" />
<Label text="Directory:" GridPane.rowIndex="2" />
<AnchorPane GridPane.columnSpan="2" GridPane.rowIndex="3">
<children>
<TextField fx:id="directoryTextField" editable="false" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="60.0" />
<Button onAction="#handleChangeDirectoryBtnClick" text="Change" AnchorPane.rightAnchor="0.0" />
</children>
</AnchorPane>
<HBox alignment="CENTER" GridPane.columnSpan="2" GridPane.rowIndex="4">
<children>
<Button fx:id="saveBtn" onAction="#handleSaveBtnClick" text="Save" />
</children>
</HBox>
</children>
<padding>
<Insets bottom="3.0" left="3.0" right="3.0" top="3.0" />
</padding>
</GridPane>预览：
Stack Overflow用户
发布于 2020-05-26 16:35:57
FileChooser不会在存储设备上创建文件，如果文件存在，它也不会修改该文件。
这只是让用户通过保存对话框确定的File实例的一种方法。在用户选择文件之后，您需要自己保存数据：
File selectedFile = fileChooser.showSaveDialog(primaryStage);
if (selectedFile != null) {
// dialog closed by selecting a file to save the data to
// write data here yourself, e.g.
try (BufferedReader br = Files.newBufferedReader(selectedFile.toPath(), StandardCharsets.UTF_8)) {
br.write("Hello World!\n");
}
}如果写入文件可能需要很长时间，则应该将写入逻辑移动到后台线程，以避免冻结GUI。
Stack Overflow用户
发布于 2020-05-26 13:03:08
FileChooser中的筛选器仅用于显示现有文件。如果要保存具有特定扩展名的文件，则需要如下所示：
String fileName = file.toString();
if (!fileName.endsWith(".java"))
fileName += ".java";页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/62022692
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