在GUI面板中创建Java控制台

在GUI面板中创建Java控制台

这是一个正常运行的类。你可以使用以下方法将其实例安装到系统中，然后执行err：

PrintStream con=new PrintStream(new textareaOutputStream(...));System.setOut(con);System.setErr(con);

方法中正确记录和删除了文本区域中的行，

run()

以避免在控制台充斥输出时可能发生的追加和删除之间的竞争状况。最终结果对我来说也更干净。

import java.awt.*;import java.io.*;import java.util.*;import java.util.List;import javax.swing.*;public class textareaOutputStreamextends OutputStream{// *************************************************************************************************// INSTANCE MEMBERS// *************************************************************************************************private byte[]    oneByte;        // array for write(int val);private Appender  appender;       // most recent actionpublic textareaOutputStream(Jtextarea txtara) {    this(txtara,1000);    }public textareaOutputStream(Jtextarea txtara, int maxlin) {    if(maxlin<1) { throw new IllegalArgumentException("textareaOutputStream maximum lines must be positive (value="+maxlin+")"); }    oneByte=new byte[1];    appender=new Appender(txtara,maxlin);    }public synchronized void clear() {    if(appender!=null) { appender.clear(); }    }public synchronized void close() {    appender=null;    }public synchronized void flush() {    }public synchronized void write(int val) {    oneByte[0]=(byte)val;    write(oneByte,0,1);    }public synchronized void write(byte[] ba) {    write(ba,0,ba.length);    }public synchronized void write(byte[] ba,int str,int len) {    if(appender!=null) { appender.append(bytesToString(ba,str,len)); }    }@edu.umd.cs.findbugs.annotations.SuppressWarnings("DM_DEFAULT_ENCODING")static private String bytesToString(byte[] ba, int str, int len) {    try { return new String(ba,str,len,"UTF-8"); } catch(UnsupportedEncodingException thr) { return new String(ba,str,len); } // all JVMs are required to support UTF-8    }// *************************************************************************************************// STATIC MEMBERS// *************************************************************************************************    static class Appender    implements Runnable    {    private final Jtextarea  textarea;    private final int        maxLines;       // maximum lines allowed in text area    private final linkedList<Integer>   lengths;        // length of lines within text area    private final List<String>          values;         // values waiting to be appended    private int   curLength;      // length of current line    private boolean          clear;    private boolean          queue;    Appender(Jtextarea txtara, int maxlin) {        textarea =txtara;        maxLines =maxlin;        lengths  =new linkedList<Integer>();        values   =new ArrayList<String>();        curLength=0;        clear    =false;        queue    =true;        }    synchronized void append(String val) {        values.add(val);        if(queue) { queue=false; EventQueue.invokeLater(this); }        }    synchronized void clear() {        clear=true;        curLength=0;        lengths.clear();        values.clear();        if(queue) { queue=false; EventQueue.invokeLater(this); }        }    // MUST BE THE onLY METHOD THAT TOUCHES textarea!    public synchronized void run() {        if(clear) { textarea.setText(""); }        for(String val: values) { curLength+=val.length(); if(val.endsWith(EOL1) || val.endsWith(EOL2)) {     if(lengths.size()>=maxLines) { textarea.replaceRange("",0,lengths.removeFirst()); }     lengths.addLast(curLength);     curLength=0;     } textarea.append(val); }        values.clear();        clear =false;        queue =true;        }    static private final String         EOL1="n";    static private final String         EOL2=System.getProperty("line.separator",EOL1);    }}