从画图程序开始，走进GUI编程世界

indow.getFont();
  style=font.getStyle();
  size=font.getSize();
  JPanel buttonPane=new JPanel();
  buttonPane.add(ok=createButton("确认"));
  buttonPane.add(cancel=createButton("取消"));
  getContentPane().add(buttonPane,BorderLayout.SOUTH);
  JPanel dataPane=new JPanel();
  dataPane.setBorder(BorderFactory.createCompoundBorder(
       BorderFactory.createLineBorder(Color.black),
       BorderFactory.createEmptyBorder(5,5,5,5)));
  GridBagLayout gbLayout=new GridBagLayout();
  dataPane.setLayout(gbLayout);
  GridBagConstraints constraints=new GridBagConstraints();
  JLabel label=new JLabel("选择字体");
  constraints.fill=GridBagConstraints.HORIZONTAL;
  constraints.gridwidth=GridBagConstraints.REMAINDER;
  gbLayout.setConstraints(label,constraints);
  dataPane.add(label);
  GraphicsEnvironment e=GraphicsEnvironment.getLocalGraphicsEnvironment();
  String[] fonts=e.getAvailableFontFamilyNames();
  fontList=new JList(fonts);
  fontList.setValueIsAdjusting(true);
  fontList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
  fontList.setSelectedValue(font.getFamily(),true);
  fontList.addListSelectionListener(this);
  JScrollPane chooseFont=new JScrollPane(fontList);
  chooseFont.setMinimumSize(new Dimension(300,100));
  JPanel display=new JPanel();
  fontDisplay=new JLabel("字体样例:x X y Y z Z");
  fontDisplay.setPreferredSize(new Dimension(300,100));
  display.add(fontDisplay);
  JSplitPane splitPane=new JSplitPane(JSplitPane.VERTICAL_SPLIT,true,chooseFont,display);
  gbLayout.setConstraints(splitPane,constraints);
  dataPane.add(splitPane);
  JPanel sizePane=new JPanel();
  label=new JLabel("选择字体大小");
  sizePane.add(label);
  String[] sizeList={"8","10","12","14","16","18","20","22","24"};
  chooseSize=new JComboBox(sizeList);
  chooseSize.setSelectedItem(Integer.toString(size));
  chooseSize.addActionListener(this);
  sizePane.add(chooseSize);
  gbLayout.setConstraints(sizePane,constraints);
  dataPane.add(sizePane);
  JRadioButton bold=new JRadioButton("加粗",(style&Font.BOLD)>0);
  JRadioButton italic=new JRadioButton("斜体",(style&Font.ITALIC)>0);
  bold.addItemListener(new StyleListener(Font.BOLD));
  italic.addItemListener(new StyleListener(Font.ITALIC));
  JPanel stylePane=new JPanel();
  stylePane.add(bold);
  stylePane.add(italic);
  gbLayout.setConstraints(stylePane,constraints);
  dataPane.add(stylePane);
  getContentPane().add(dataPane,BorderLayout.CENTER);
  pack();
  setVisible(false);
 }
 JButton createButton(String label){
  JButton button=new JButton(label);
  button.setPreferredSize(new Dimension(80,20));
  button.addActionListener(this);
  return button;
 }
 public void actionPerformed(ActionEvent e){
  Object source=e.getSource();
  if(source==ok){
   window.setFont(font);
   setVisible(false);
  }
  else if(source==cancel)
   setVisible(false);
  else if(source==chooseSize){
   size=Integer.parseInt((String)chooseSize.getSelectedItem());
   font=font.deriveFont((float)size);
   fontDisplay.setFont(font);
   fontDisplay.repaint();
  }
 }
 public void valueChanged(ListSelectionEvent e){
  if(!e.getValueIsAdjusting()){
   font=new Font((String)fontList.getSelectedValue(),style,size);
   fontDisplay.setFont(font);
   fontDisplay.repaint();
  }
 }
 class StyleListener implements ItemListener{
  private int astyle;
  public StyleListener(int style){
   this.astyle=style;
  }
  public void itemStateChanged(ItemEvent e){
   if(e.getStateChange()==ItemEvent.SELECTED)
    style|=astyle;
   else style&=~astyle;
   font=font.deriveFont(style);
   fontDisplay.setFont(font);
   fontDisplay.repaint();
  }
 }  
}

package boya;
import java.awt.*;
import java.io.File;
public interface ID{
 int LINE=101;
 int RECTANGLE=102;
 int CIRCLE=103;
 int CURVE=104;
 int TEXT=105;
 int DEFAULT_ELEMENT_TYPE=LINE;
 Color DEFAULT_ELEMENT_COLOR=Color.red;
 Font DEFAULT_FONT=new Font("宋体",Font.PLAIN,20);
 File DEFAULT_DIR=new File("c:/My Draw");
 String DEFAULT_FILENAME="Untitled.ice";
}

package boya;
import java.awt.*;
import javax.swing.*;
import javax.swing.border.*;
class StatusBar extends JPanel implements ID{
 private StatusPane colorPane=new StatusPane("红色");
 private StatusPane typePane=new StatusPane("直线");
 class StatusPane extends JLabel{
  private Font paneFont=new Font("宋体",Font.PLAIN,12);
  public StatusPane(String text){
   setForeground(Color.black);
   setFont(paneFont);
   setHorizontalAlignment(CENTER);
   setBorder(BorderFactory.createBevelBorder(BevelBorder.LOWERED));;
   setPreferredSize(new Dimension(70,18));
   setText(text);
  }
 }
 public StatusBar(){
  setLayout(new FlowLayout(FlowLayout.RIGHT,10,3));
  setBorder(BorderFactory.createLineBorder(Color.LIGHT_GRAY));
  setColorPane(DEFAULT_ELEMENT_COLOR);
  setTypePane(DEFAULT_ELEMENT_TYPE);
  add(colorPane);
  add(typePane);
 }
 public void setColorPane(Color color){
  String text;
  if(color.equals(Color.red))
   text="红色";
  else if(color.equals(Color.yellow))
   text="黄色";
  else if(color.equals(Color.green))
   text="绿色";
  else if(color.equals(Color.blue))
   text="蓝色";
  else text="未定义";
  colorPane.setText(text);
 }
 public void setTypePane(int element){
  String text;
  switch(element){
   case LINE:
    text="直线";
    break;
   case RECTANGLE:
    text="矩形";
    break;
   case CIRCLE:
    text="圆";
    break;
   case CURVE:
    text="曲线";
    break;
   case TEXT:
    text="文字";
    break;
   default:
    text="错误";
    break;
  }
  typePane.setText(text);
 }
}

最后还可以将生成的代码放置到JAR包中，这样就可以在安装JVM的环境下，使
此JAR包作为可执行文件了。

包的结构如下：
--Draw
----boya
----META-INF
----res

其分别为包、配置文件、资源

在META-INF中建立文件MANIFEST.MF写入：
Manifest-Version: 1.0
Main-Class: boya.Draw

这样这个包就完成了
Main-Class: boya.Draw