我有一个类(如下所示),扩展了JPanel并包含一个JTextPane.我想将System.out和System.err重定向到我的JTextPane.我的班级似乎没有工作.当我运行它,它会重定向系统打印,但它们不打印到我的JTextPane.请帮忙！
注意：只有应用程序启动时,才会重定向呼叫.但任何时候,发布后,System.out调用不会被重定向到JTextPane. (即,如果我放置一个System.out.prinln();在类中,它将被调用,但是如果它被放置在一个actionListener中供以后使用,它不会重定向).
public class OSXConsole extends JPanel {
public static final long serialVersionUID = 21362469L;
private JTextPane textPane;
private PipedOutputStream pipeOut;
private PipedInputStream pipeIn;
public OSXConsole() {
super(new BorderLayout());
textPane = new JTextPane();
this.add(textPane,BorderLayout.CENTER);
redirectSystemStreams();
textPane.setBackground(Color.GRAY);
textPane.setBorder(new EmptyBorder(5,5,5));
}
private void updateTextPane(final String text) {
SwingUtilities.invokelater(new Runnable() {
public void run() {
Document doc = textPane.getDocument();
try {
doc.insertString(doc.getLength(),text,null);
} catch (BadLocationException e) {
throw new RuntimeException(e);
}
textPane.setCaretPosition(doc.getLength() - 1);
}
});
}
private void redirectSystemStreams() {
OutputStream out = new OutputStream() {
@Override
public void write(final int b) throws IOException {
updateTextPane(String.valueOf((char) b));
}
@Override
public void write(byte[] b,int off,int len) throws IOException {
updateTextPane(new String(b,off,len));
}
@Override
public void write(byte[] b) throws IOException {
write(b,b.length);
}
};
System.setout(new PrintStream(out,true));
System.setErr(new PrintStream(out,true));
}
}
解决方法
流水流总是混淆我,这就是为什么我的Message Console解决方案不使用它们.无论如何,这里是我尝试使用管道流的控制台.几个差异：
a)它使用JTextArea,因为JTextArea比仅显示文本的JTextPane更有效率.当然,如果你打算为文本添加属性,那么你需要一个文本窗格.
b)此解决方案使用线程.我确定我读到某个地方必须防止阻塞输出.无论如何,它在我的简单测试用例中起作用.
import java.io.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
public class Console implements Runnable
{
JTextArea displayPane;
BufferedReader reader;
private Console(JTextArea displayPane,PipedOutputStream pos)
{
this.displayPane = displayPane;
try
{
PipedInputStream pis = new PipedInputStream( pos );
reader = new BufferedReader( new InputStreamReader(pis) );
}
catch(IOException e) {}
}
public void run()
{
String line = null;
try
{
while ((line = reader.readLine()) != null)
{
// displayPane.replaceSelection( line + "\n" );
displayPane.append( line + "\n" );
displayPane.setCaretPosition( displayPane.getDocument().getLength() );
}
System.err.println("im here");
}
catch (IOException ioe)
{
JOptionPane.showMessageDialog(null,"Error redirecting output : "+ioe.getMessage());
}
}
public static void redirectOutput(JTextArea displayPane)
{
Console.redirectOut(displayPane);
Console.redirectErr(displayPane);
}
public static void redirectOut(JTextArea displayPane)
{
PipedOutputStream pos = new PipedOutputStream();
System.setout( new PrintStream(pos,true) );
Console console = new Console(displayPane,pos);
new Thread(console).start();
}
public static void redirectErr(JTextArea displayPane)
{
PipedOutputStream pos = new PipedOutputStream();
System.setErr( new PrintStream(pos,pos);
new Thread(console).start();
}
public static void main(String[] args)
{
JTextArea textArea = new JTextArea();
JScrollPane scrollPane = new JScrollPane( textArea );
JFrame frame = new JFrame("Redirect Output");
frame.setDefaultCloSEOperation( JFrame.EXIT_ON_CLOSE );
frame.getContentPane().add( scrollPane );
frame.setSize(200,100);
frame.setVisible(true);
Console.redirectOutput( textArea );
final int i = 0;
Timer timer = new Timer(1000,new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
System.out.println( new java.util.Date().toString() );
System.err.println( System.currentTimeMillis() );
}
});
timer.start();
}
}