英文:
saving a file fiormat pdf file with java
问题
我正在尝试创建一个PDF文件，然后使用文件选择器将其保存到设备上。
保存部分是有效的，但当我尝试打开文件时，它无法打开。
以下是我的代码：
FileChooser fc = new FileChooser();
fc.getExtensionFilters().add(new FileChooser.ExtensionFilter("PDF文件", "*.pdf"));
fc.setTitle("保存为PDF");
fc.setInitialFileName("未命名.pdf");
Stage stg = (Stage) ((Node) event.getSource()).getScene().getWindow();
File file = fc.showSaveDialog(stg);
if (file != null) {
String str = file.getAbsolutePath();
FileOutputStream fos = new FileOutputStream(str);
Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(str));
document.open();
document.add(new Paragraph("一个你好世界的PDF文档。"));
document.close();
writer.close();
fos.flush();
}
当我尝试打开文件时，出现错误，显示文件已被其他用户打开或正在使用。
英文:
I am trying to create a pdf file then save it to device using fileChooser
It works the saving but when i go to the file to open it it doesn't open
here is my code
FileChooser fc = new FileChooser();
fc.getExtensionFilters().add(new FileChooser.ExtensionFilter("PDF File", "*.pfd"));
fc.setTitle("Save to PDF"
);
fc.setInitialFileName("untitled.pdf");
Stage stg = (Stage) ((Node) event.getSource()).getScene().getWindow();
File file = fc.showSaveDialog(stg);
if (file != null) {
String str = file.getAbsolutePath();
FileOutputStream fos = new FileOutputStream(str);
Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(str));
document.open();
document.add(new Paragraph("A Hello World PDF document."));
document.close();
writer.close();
fos.flush();
}
when i open it this is the error showing it says the file is either opened or used by another user
答案1
得分: 0
你的代码没有调用close()方法关闭FileOutputStream，这可能会导致资源泄漏，并且文档可能无法正确访问，甚至可能损坏。
当你使用实现了AutoClosable接口的FileOutputStream时，有两个选择：
手动调用close()关闭FileOutputStream：
FileChooser fc = new FileChooser();
fc.getExtensionFilters().add(new FileChooser.ExtensionFilter("PDF 文件", "*.pdf"));
fc.setTitle("保存为 PDF");
fc.setInitialFileName("未命名.pdf");
Stage stg = (Stage) ((Node) event.getSource()).getScene().getWindow();
File file = fc.showSaveDialog(stg);
if (file != null) {
String str = file.getAbsolutePath();
FileOutputStream fos = new FileOutputStream(str);
Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(str));
document.open();
document.add(new Paragraph("一个你好世界的 PDF 文档。"));
document.close();
writer.close();
fos.flush();
/*
* 唯一与你的代码不同的地方在于下面这一行
*/
fos.close();
}
或者使用try与资源一起使用，详情请参阅这篇帖子。
英文:
Your code does not close() the FileOutputStream which may cause a resource leak and the document is not properly accessible, maybe even corrupted.
When you work with a FileOutputStream that implements AutoClosable, you have two options:
close() the FileOutputStream manually:
FileChooser fc = new FileChooser();
fc.getExtensionFilters().add(new FileChooser.ExtensionFilter("PDF File", "*.pfd"));
fc.setTitle("Save to PDF");
fc.setInitialFileName("untitled.pdf");
Stage stg = (Stage) ((Node) event.getSource()).getScene().getWindow();
File file = fc.showSaveDialog(stg);
if (file != null) {
String str = file.getAbsolutePath();
FileOutputStream fos = new FileOutputStream(str);
Document document = new Document();
PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream(str));
document.open();
document.add(new Paragraph("A Hello World PDF document."));
document.close();
writer.close();
fos.flush();
/*
* ONLY DIFFERENCE TO YOUR CODE IS THE FOLLOWING LINE
*/
fos.close();
}
}
or use a try with resources read about that in this post, for example.
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