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J2EE综合--总结在java编程中的经验教训

更新时间: 2008-08-29 10:37:25来源: 粤嵌教育浏览量:1248

  【赛迪网-IT技术报道】我实际工作中的经验教训,在这里与大家共享,空的字符串是””,不带空格outputStream在打印时,打印的内容后面不要加\n,否则对方接受和判断不正确!


  G:\PROJECTION\IC2N\1c2njava>javac Jsubnetframe.java


  Jsubnetframe.java:22: Jsubnetframe should be declared abstract; it does not defi


  ne valueChanged(javax.swing.event.ListSelectionEvent) in Jsubnetframe


  public class Jsubnetframe extends JFrame implements ListSelectionListener {


  ^


  Jsubnetframe.java:68: cannot resolve symbol


  symbol : class TableModel


  location: class Jsubnetframe


  TableModel dataModel = new AbstractTableModel() {


  ^


  Jsubnetframe.java:68: cannot resolve symbol


  symbol : class AbstractTableModel


  location: class Jsubnetframe


  TableModel dataModel = new AbstractTableModel() {


  ^


  Jsubnetframe.java:89: addActionListener(java.awt.event.ActionListener) in javax.


  swing.AbstractButton cannot be applied to (Jsubnetframe)


  cancelb.addActionListener(this);


  ^


  Note: Jsubnetframe.java uses or overrides a deprecated API.


  Note: Recompile with -deprecation for details.


  4 errors


  原因是没有import javax.swing.table.*;


  G:\PROJECTION\IC2N\1c2njava>javac Jhpportframe.java


  Jhpportframe.java:27: Jhpportframe should be declared abstract; it does not defi


  ne mousePressed(java.awt.event.MouseEvent) in Jhpportframe


  public class Jhpportframe extends JFrame implements


  ^


  Note: Jhpportframe.java uses or overrides a deprecated API.


  Note: Recompile with -deprecation for details.


  1 error


  Jhpportframe should be declared abstract; it does not defi   原因是因为在这里必须用MouseListener 的相关方法进行覆盖,也就是说必须加入如下的方法:


  public void mousePressed(MouseEvent evt) {//if (audio != null) audio.play();}


  public void mouseEntered (MouseEvent me) {}


  public void mouseExited (MouseEvent me) {}


  public void mouseReleased(MouseEvent me) {}


  鼠标左键和右件的事件获取:


  public void mousePressed(MouseEvent evt) {


  Point point1=evt.getPoint();


  int x,y;


  int onmask = evt.BUTTON1_DOWN_MASK;//左键的ID号


  if ((evt.getModifiersEx() & onmask ) == onmask)   // 点击左键时


  {


  }


  else                     //点击右键时


  抽象类,不能进行初始化或者生成实例


  hpportimg=new Image(getDocumentBase(),”aaa.gif”);


  这句话是错的,因为Image()是抽象类,不能进行初始化或者生成实例.,应该用:


  hpportimg=getImage(“adf.gif”);


  并且应该注意它不能放在构造函数中,而应该放在INIT()等方法中.


  各种动作和事件的处理:


  监视键盘的动作,用usertf.addKeyListener(this);它的接口软件包是KeyListener,应该import java.awt.event.*;  必须重载的接口函数是


  public void keyPressed(KeyEvent e){}


  public void keyReleased(KeyEvent e){}


  public void keyTyped(KeyEvent e){}


  监视焦点的动作,用usertf.add FocusListener (this);它的接口软件包是FocusListener应该import java.awt.event.*;  必须重载的接口函数是


  public void focusLost(FocusEvent e) { }


  public void focusGained(FocusEvent e) {}


  监视鼠标的动作,用usertf.addMouseListener(this);它的接口软件包是MouseyListener,应该import java.awt.event.*;


  //必须增加MouseListener(this) 或component. MouseListener(this)


  必须重载的接口函数是


  public void mouseClicked(MouseEvent e){ }


  public void mousePressed(MouseEvent evt) {}


  public void mouseEntered (MouseEvent me) {}


  public void mouseExited (MouseEvent me) {}


  public void mouseReleased(MouseEvent me) {}

  监视鼠标移动的动作,用usertf.addMouseListener(this);它的接口软件包是MouseyMotionListener,应该import java.awt.event.*;  必须重载的接口函数是


  public void mouseMoved(MouseEvent e){}


  public void mouseDragged(MouseEvent e){ }


  以上各种事件必须在组件上增加相应的侦听,如


  user.addKeyListener(this);


  pass.addKeyListener(this);


  user.addFocusListener(this);


  pass.addFocusListener(this);


  按钮事件的执行在JAVA2中应该用下列函数,无须重载:


  public void actionPerformed(ActionEvent ae) {


  JButton source=(JButton)ae.getSource();


  if(source==okb)


  { slkdfjalskdjflaksdjlfjads;flkjasld;kjfl;kasjdfl;k}


  焦点事件:focusLost(),focusGain()


  transferFocus()是将焦点传递到下一个组件


  requestFocus()是将焦点传递到指定的组件,


  if(e.getComponent()==user) user.transferFocus();


  else if(e.getComponent()==pass) pass.transferFocus();


  else if(e.getComponent()==ok) ok.transferFocus();


  经过观察发现,焦点可以在文本框上传递,但是在按钮上好象没法传递.


  在表格中


  subnettable.reshape(0,0,300,200); //一定要,用以刷新屏幕


  JTable中的每一行可否设置不同的背景颜色???


  可以的,使用自己的TableCellRenderer从TableModel中的value获取颜色值.


  请参见:


  http://www2.gol.com/users/tame/swing/examples/


  有关玻璃层:


  1、 GLASSPANE不能设置大小,它将布满整个工作区, //jtv.reshape(300,300,300,200); 没用


  2、 先建立一个JComponent 的组件,jtv=new Jtopview(jlp);其中jlp是新建母窗口的JLayeredPane


  3、 将这个组建用setGlassPane(jtv)方法设置


  4、 如果要求它透明,这一句不能少jtv.setOpaque(false);


  5、 这一句是显示的,也不能少jtv.setVisible(true);


  6、 玻璃层下面层的组建获取动作用redispatchMouseEvent(MouseEvent me)


  这段代码是我在英文网址上拿下来修改的,同时参照了<<精通JAVA2>>P437页


  public void redispatchMouseEvent(MouseEvent me,boolean repaint)


  {


  //能够直接取到的组件,用广义的component 就可以了


  Point point=me.getPoint();


  int eventID = me.getID();


  Component component=jlp.getComponentAt(point);


  Point componentPoint = SwingUtilities.convertPoint(


  jlp,


  point,


  component);


  boolean componentBOOL=component.contains(componentPoint );


  if(componentBOOL){


  //System.out.println("7777777777777777" component);


  component.dispatchEvent(new MouseEvent(component,eventID,me.getWhen(),me.getModifiers(),


  componentPoint.x,componentPoint.y,me.getClickCount(),me.isPopupTrigger()));


  }


  ////不能够直接取到的组件,用具体的组件名字


  Point alarmtablePoint = SwingUtilities.convertPoint(


  jlp,


  point,


  alarmtable);


  boolean alarmtableBOOL= alarmtable.contains(alarmtablePoint );


  if (alarmtableBOOL ) {


  alarmtable.dispatchEvent(new MouseEvent(alarmtable,eventID,me.getWhen(),


  me.getModifiers(),


  alarmtablePoint.x,


  alarmtablePoint.y,


  me.getClickCount(),


  me.isPopupTrigger()));


  }


  }

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