J2EE综合--总结java编程中的经验教训
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OKLinux www.oklinux.cn 2008-01-23 来源:赛迪网 gdws 会员收藏 游客收藏 |
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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,否则对方接受和判定不正确 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”); 并且应该注重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. 共2页: 上一页 1 [2] 下一页 |
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