Question

我在javaclass中有简单的代码。

public class JavaApplication1 {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        System.out.println("hello");
    }

}

我需要在运行时在Jtextfield中显示“hello”输出...作为一个更新鲜的我不知道该怎么做..

Answer 1

您需要TextAreaOutputStream，例如

import java.io.IOException;    
import java.io.OutputStream;

import javax.swing.JTextArea;

    /**

     * TextAreaOutputStream creates an outputstream that will output to the
     * given textarea. Useful in setting System.out
     */

    public class TextAreaOutputStream extends OutputStream {
        public static final int DEFAULT_BUFFER_SIZE = 1;

        JTextArea mText;
        byte mBuf[];
        int mLocation;
        public TextAreaOutputStream(JTextArea component) {
            this(component, DEFAULT_BUFFER_SIZE);
        }

        public TextAreaOutputStream(JTextArea component, int bufferSize) {
            mText = component;
            if (bufferSize < 1) bufferSize = 1;
            mBuf = new byte[bufferSize];
            mLocation = 0;
        }

        @Override
        public void write(int arg0) throws IOException {
            //System.err.println("arg = "  + (char) arg0);
            mBuf[mLocation++] = (byte)arg0;
            if (mLocation == mBuf.length) {
                flush();
            }
        }

        public void flush() {
            mText.append(new String(mBuf, 0, mLocation));
            mLocation = 0;        
        }

    }

创建它，然后使用System.setOut（OutputStream）将System.out发送到文本区域

Answer 2

最简单的方法是：首先用文本框设置一个框架，然后直接打印到它。

public static void main(String[] args) {
    JFrame frame = new JFrame();

    JTextField field = new JTextField();
    frame.add(field);

    frame.pack();
    frame.setVisible(true);

    OutputStream out = new OutputStream() {
        @Override
        public void write(int b) throws IOException {
        }
    };

    class JTextFieldPrintStream extends PrintStream {
        public JTextFieldPrintStream(OutputStream out) {
            super(out);
        }
        @Override
        public void println(String x) {
            field.setText(x);
        }
    };
    JTextFieldPrintStream print = new JTextFieldPrintStream(out);
    System.setOut(print);

    System.out.println("hello");
}

如何从system.out.println显示输出到Jtextfield

2 个答案: