大家好，我是 JSF 新手，
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，我该如何执行此操作？对于像我这样的初学者来说，还有什么好的 JSF 教程吗？谢谢:)
JAVA代码是一段简单的代码，允许用户选择一个txt文件然后打印它。
目的是创建一个网络应用程序以允许打印文档
这是我希望运行的 JAVA 代码:
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;
}
}
最佳答案
对于实现选择要上传的文件然后使用 JSF 显示它的具体功能要求，您的方向是错误的。
您正在尝试使用 Swing/AWT 选择文件。虽然这对于基于桌面的应用程序来说可能确实是正确的方法，但对于基于 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，而 Web 浏览器最终又运行所有获得的 HTML/CSS/JS 代码。因此请注意，Java/JSF 运行在运行 Web 服务器的物理机中。因此，Swing/AWT 也会在运行 Web 服务器的物理机中运行，因此绝对不会在运行 Web 浏览器的物理机中运行。基本上，当 Swing/AWT 显示某些 UI 时，它将显示在附加到 Web 服务器的监视器中，而不是附加到 Web 浏览器的监视器中。
您需要使用 HTML/CSS/JS 而不是 Java 来实现您的功能需求。您需要以这样的方式编写 JSF 代码，使其生成适合所需任务的特定 HTML/CSS/JS 代码。
在您的具体情况下，您想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"> 表示。元素。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:
<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>
用这个bean
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，因此上述代码按原样工作)
另请参阅:
关于swing - 如何在 JSF 页面中执行 Java Swing 代码，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/55773100/