如何在JSF页面中执行Java Swing代码 [英] How to execute Java Swing code in a JSF page
问题描述
您好，我是JSF的新手，
Hi all i'm new to JSF,
我已经创建了一个Java文件，当用户按下XHTML页面上的按钮时，我需要运行该文件，我该怎么做?对于像我这样的初学者来说，还有针对JSF的好的教程吗?谢谢:)
I have created a java file, I need this to run when a user presses a button on the XHTML page, how do i do this ? also are there any good tutorials for beginners like me out there for JSF ? Thanks :)
JAVA代码是一段简单的代码，它允许用户选择一个txt文件，然后进行打印.
The JAVA code is a simple piece of code that allows a user to select a txt file and then print it.
目标是创建一个允许打印文档的网络应用程序
The aim is to create a web app to allow printing of documents
这是我希望运行的JAVA代码:
Here is the JAVA code I wish to run:
import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.awt.print.*;
import java.text.*;
import java.io.*;
import javax.swing.*;
import java.util.List;
import java.util.ArrayList;
public class PrintText implements Printable {
private String text; // Constructor argument for AttributedString.
// Below the code will allow the user to select a file and then print out the contents of the file
public static void main(String[] args) throws IOException {
new PrintText();
}
public PrintText() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
//selects the file
JFileChooser chooser = new JFileChooser();
chooser.showOpenDialog(null);
File file = chooser.getSelectedFile();
String filename = file.getName();
//System.out.println("You have selected: " + filename); testing to see if file seleected was right
String path = file.getAbsolutePath();
//Reads contents of file into terminal
//FileReader fr = new FileReader("filename");
// FileReader fr = new FileReader("D:/Documents/" + "filename"));
BufferedReader br = null;
try {
br = new BufferedReader(new FileReader(path));
StringBuilder stringBuilder = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
//System.out.println(line); //This is now not needed, was used to test to see if the contents was recieved corrently
stringBuilder.append(line).append("\n");
}
text = stringBuilder.toString();;
printer();
} catch (IOException exp) {
exp.printStackTrace();
} finally {
try {
br.close();
} catch (Exception e) { e.printStackTrace(); }
}
//fr.close();
}
});
}
//Testing
//private static final String mText =
// "This is a test to see if this text will be printed "; //This works perfectly fine
//AttributedString mStyledText = new AttributedString(mText);
/**
* Print a single page containing some sample text.
*/
public void printer() {
/* Get the representation of the current printer and
* the current print job.
*/
PrinterJob printerJob = PrinterJob.getPrinterJob();
/* Build a book containing pairs of page painters (Printables)
* and PageFormats.
*/
Book book = new Book();
book.append(this, new PageFormat());
/* Set the object to be printed (the Book) into the PrinterJob.
* Doing this before bringing up the print dialog allows the
* print dialog to correctly display the page range to be printed
* and to dissallow any print settings not appropriate for the
* pages to be printed.
*/
printerJob.setPageable(book);
/* Show the print dialog to the user. If the user cancels the print dialog then false
* is returned. If true is returned we go ahead and print.
*/
boolean doPrint = printerJob.printDialog();
if (doPrint) {
try {
printerJob.print();
} catch (PrinterException exception) {
System.err.println("Printing error: " + exception);
}
}
}
/**
* Print a page of text.
*/
public int print(Graphics g, PageFormat format, int pageIndex) {
AttributedString mStyledText = new AttributedString(text);
Graphics2D g2d = (Graphics2D) g;
g2d.translate(format.getImageableX(), format.getImageableY());
g2d.setPaint(Color.black);// Sets text colour
Point2D.Float pen = new Point2D.Float();
AttributedCharacterIterator charIterator = mStyledText.getIterator();
LineBreakMeasurer measurer = new LineBreakMeasurer(charIterator, g2d.getFontRenderContext());
float wrappingWidth = (float) format.getImageableWidth();
while (measurer.getPosition() < charIterator.getEndIndex()) {
TextLayout layout = measurer.nextLayout(wrappingWidth);
pen.y += layout.getAscent();
float dx = layout.isLeftToRight() ? 0 : (wrappingWidth - layout.getAdvance());
layout.draw(g2d, pen.x + dx, pen.y);
pen.y += layout.getDescent() + layout.getLeading();
}
return Printable.PAGE_EXISTS;
}
}
推荐答案
要实现具体的功能要求，即选择要上传的文件，然后使用JSF进行显示，您的方向就错了.
You're going in the wrong direction as to achieving the concrete functional requirement of selecting a file for upload and then displaying it using JSF.
您正尝试使用Swing/AWT选择文件.尽管这对于基于桌面的应用程序确实是正确的方法，但是对于基于Web的应用程序来说这完全是错误的方法.在基于Web的应用程序中，Java/JSF代码在Web服务器中运行，并生成一堆HTML/CSS/JS代码，这些代码通过网络发送到Web浏览器，然后由Web浏览器最终运行所有获得的HTML/CSS/JS代码.因此请注意，Java/JSF在运行Web服务器的物理计算机中运行.因此，Swing/AWT也将在运行Web服务器的物理机中运行，因此绝对不在运行Web浏览器的物理机中运行.基本上，当Swing/AWT显示一些UI时，它将显示在连接到Web服务器的监视器中，而不是显示在连接到Web浏览器的监视器中.
You're trying to select a file using Swing/AWT. Whilst this may indeed be the right approach for desktop based applications, this is totally the wrong approach for web based applications. In web based applications, Java/JSF code runs in the webserver and produces a bunch of HTML/CSS/JS code which get sent over network to the webbrowser who in turn finally runs all that obtained HTML/CSS/JS code. Note thus that Java/JSF runs in the physical machine where the webserver runs. So, Swing/AWT would also run in the physical machine where the webserver runs and thus definitely not in the physical machine where the webbrowser runs. Basically, when Swing/AWT shows some UI, it would be shown in the monitor attached to the webserver, not the one attached to the webbrowser.
您需要使用HTML/CSS/JS而不是Java来实现功能要求.您需要以这样的方式编写JSF代码，使其准确地生成适合于所需任务的特定HTML/CSS/JS代码.
You need to achieve your functional requirement in HTML/CSS/JS instead of in Java. You need to write JSF code in such way that it generates exactly the specific HTML/CSS/JS code suitable for the needed task.
在特定情况下，您要上传文件并显示其内容.在HTML世界中，文件选择器由<input type="file">元素表示.在标准JSF中，您可以使用<h:inputFile>组件生成该HTML.这是一个启动示例:
In your specific case, you want to upload a file and show its content. In HTML world, a file chooser is represented by the <input type="file"> element. In standard JSF, you can use <h:inputFile> component generate that HTML. Here's a kickoff example:
<h:form enctype="multipart/form-data">
<h:inputFile value="#{bean.file}" />
<h:commandButton value="Submit" action="#{bean.process}" />
<h:messages />
</h:form>
<pre>#{bean.content}</pre>
与此豆
private Part file; // +getter+setter
private String content; // +getter
public void process() throws IOException {
content = IOUtils.toString(file.getInputstream(), "UTF-8");
}
(注意:IOUtils是Apache Commons IO的一部分，因此上面的代码按原样工作)
(note: IOUtils is part of Apache Commons IO, so the above code works as-is)
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