java编程实例,利用jbulider环境编程. 不错啊

				package untitled1;								import java.awt.*;				import java.awt.event.*;				import java.applet.*;				import com.borland.jbcl.layout.*;								public class valia extends Applet {				  boolean flag = false,flag1 = false,flag2 = false;				  double num;				  boolean isStandalone = false;				  TextField text1 = new TextField();				  XYLayout xYLayout1 = new XYLayout();				  Label label1 = new Label();				  Checkbox checkbox1 = new Checkbox();				  Checkbox checkbox2 = new Checkbox();				  Label label2 = new Label();				  /**Get a parameter value*/				  public String getParameter(String key, String def) {				    return isStandalone ? System.getProperty(key, def) :				      (getParameter(key) != null ? getParameter(key) : def);				  }								  /**Construct the applet*/				  public valia() {				  }				  /**Initialize the applet*/				  public void init() {				    try {				      jbInit();				    }				    catch(Exception e) {				      e.printStackTrace();				    }				  }				  /**Component initialization*/				  private void jbInit() throws Exception {				    text1.setFont(new java.awt.Font("Dialog", 0, 16));				    text1.setText("0");				    text1.addFocusListener(new java.awt.event.FocusAdapter() {				      public void focusLost(FocusEvent e) {				        text1_focusLost(e);				      }				    });				    this.setLayout(xYLayout1);				    label1.setFont(new java.awt.Font("Dialog", 0, 16));				    label1.setText("输入数据");				    checkbox1.setLabel("双精度");				    checkbox1.addItemListener(new java.awt.event.ItemListener() {				      public void itemStateChanged(ItemEvent e) {				        checkbox1_itemStateChanged(e);				      }				    });				    checkbox2.setLabel("整形");				    checkbox2.addItemListener(new java.awt.event.ItemListener() {				      public void itemStateChanged(ItemEvent e) {				        checkbox2_itemStateChanged(e);				      }				    });				    label2.setFont(new java.awt.Font("Dialog", 0, 16));				    label2.setText("转换成");				    this.add(text1,    new XYConstraints(156, 70, 80, -1));				    this.add(label1,     new XYConstraints(50, 70, 80, -1));				    this.add(checkbox1, new XYConstraints(155, 114, 72, 27));				    this.add(checkbox2,  new XYConstraints(155, 152, 69, 25));				    this.add(label2,  new XYConstraints(50, 110, 83, 27));				  }				  /**Get Applet information*/				  public String getAppletInfo() {				    return "Applet Information";				  }				  /**Get parameter info*/				  public String[][] getParameterInfo() {				    return null;				  }								  void checkbox1_itemStateChanged(ItemEvent e) {				      if (flag){				         if (checkbox1.getState()){				             flag1 = true;				         }				         else				             flag1 = false;				         repaint();				      }				  }								  void text1_focusLost(FocusEvent e) {				      String str = text1.getText() ;				      if (str!=null){				          try{				              num = Double.parseDouble(str);				              flag = true;				          }				          catch(Exception ex){}				      }				      repaint();				  }								  void checkbox2_itemStateChanged(ItemEvent e) {				      if (flag){				         if (checkbox2.getState()){				             flag2 = true;				         }				         else				             flag2 = false;				         repaint();				      }				  }				  public void paint(Graphics g){				      if (flag1 == true){				          g.drawString(String.valueOf(num),100,200);				      }				      if (flag2 == true){				          g.drawString(String.valueOf((int)(num)),100,250);				      }				  }												}