通过实例可以更好的了解java

     a=new Object[30][6];
     table=new JTable(a,columnName);
     setSize(300,300);setVisible(true);
     button=new JButton("确定");
     addWindowListener(new WindowAdapter()
     {public void windowClosing(WindowEvent e)
       { System.exit(0);}} ); 
     button.addActionListener(this);
     p_bar=new JProgressBar(JProgressBar.VERTICAL,0,50);
     p_bar.setStringPainted(true) ; 
     container=getContentPane();
     container.add(button,BorderLayout.SOUTH);
     container.add(new JScrollPane(table),BorderLayout.CENTER);
     container.add(p_bar,BorderLayout.WEST);  
    }
 public void actionPerformed(ActionEvent evt)
  {if(evt.getSource()==button)
   {int i=0;
    try{Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");  }
    catch(ClassNotFoundException e){}
    try
{con=DriverManager.getConnection("jdbc:odbc:redsun","snow","ookk");
       sql=con.createStatement();
       rs=sql.executeQuery("SELECT * FROM chengjibiao");
       while(rs.next())
       {xuehao=rs.getString(1);   name=rs.getString(2);    date  =rs.getDate(3); 
        math=rs.getInt("数学");    physics=rs.getInt("物理");   english=rs.getInt("英语");
        a[i][0]=xuehao;a[i][1]=name;      a[i][2]=date;   a[i][3]=String.valueOf(math);
       a[i][4]=String.valueOf(physics);   a[i][5]=String.valueOf(english);
        i++;
        p_bar.setValue(i);p_bar.setString("查询了"+i+"条记录");
       } pack();
      con.close();
     }
    catch(SQLException e1) {}
   }   
  } 
}
public class Example25_27
{ public static void main(String args[])
  {ResultWin win=new ResultWin(); win.pack();
 }
}



25-例子28
import javax.swing.*;
import java.awt.*;
import java.awt.event.*; 
public class Example24_28 extends JApplet 
{ Container con; 
  public void init()
 {con=getContentPane();  
  JMenuBar menubar=new JMenuBar();//菜单条对象
  con.add(menubar,BorderLayout.NORTH);//增加菜单条到内容窗格
  JMenu fileMenu=new JMenu("文件"); //3个菜单对象
  JMenu editMenu=new JMenu("编辑");
  JMenu helpMenu=new JMenu("帮助");
  JMenuItem item1=new JMenuItem("打开");
  JMenuItem  item2=new JMenuItem("保存"); //创建6个菜单项。
  fileMenu.add(item1); fileMenu.add(item2);
  menubar.add(fileMenu);  menubar.add(editMenu); 
  menubar.add(helpMenu); 
 }
}



25-例子29
import javax.swing.*;
import java.awt.*;
import java.awt.event.*; 
class MenuWin extends JFrame implements ActionListener
{ Container con;JMenuItem item1; 
 MenuWin() 
 {con=getContentPane();
  setSize(300,250);setVisible(true);  
  JMenuBar menubar=new JMenuBar();//菜单条对象
  con.add(menubar,BorderLayout.NORTH);//增加菜单条到内容窗格
  JMenu fileMenu=new JMenu("文件"); //3个菜单对象
  JMenu editMenu=new JMenu("编辑");
  JMenu helpMenu=new JMenu("帮助");
  item1=new JMenuItem("打开");
  JMenuItem  item2=new JMenuItem("保存"); //创建6个菜单项。
  fileMenu.add(item1); fileMenu.add(item2);
  menubar.add(fileMenu);  menubar.add(editMenu); 
  menubar.add(helpMenu); 
  item1.addActionListener(this);
 }
 public void actionPerformed(ActionEvent e)
 {if(e.getSource()==item1)
  {JFileChooser c=new JFileChooser();
    c.showOpenDialog(null);  
  }
 }
}
public class Example25_29
{static void main(String args[])
 {MenuWin win=new MenuWin() ;win.pack();
}
}



25-例子30
import javax.swing.*;import java.awt.*;
import java.awt.event.*; 
class ToolWin extends JFrame implements ActionListener
{ JButton button1,button2; JToolBar bar; Container con;
 ToolWin() 
 {con=getContentPane();
  setSize(300,250);setVisible(true);  
  Icon open_icon =new ImageIcon("open.gif");
  Icon save_icon =new ImageIcon("save.gif");
  button1=new JButton(open_icon); button2=new JButton(save_icon);
  bar=new JToolBar();//工具条对象
  bar.add(button1);bar.add(button2);
  con.add(bar,BorderLayout.NORTH);
  button1.addActionListener(this);
  button1.setToolTipText("open");//设置组件的提示文字
  button2.setToolTipText("save");
 }
 public void actionPerformed(ActionEvent e)
 {if(e.getSource()==button1)
  {JFileChooser c=new JFileChooser();
    c.showOpenDialog(null);  
  }
 }
}
public class Example25_30
{static void main(String args[])
 {ToolWin win=new ToolWin() ;win.pack();
 }
}



25-例子31
import javax.swing.*;import javax.swing.tree.*;
import java.awt.*;
public class Mytree extends JApplet
{ public void init()
  {Container con=getContentPane();
   DefaultMutableTreeNode root=new DefaultMutableTreeNode("c:\\");//树的根节点。
   DefaultMutableTreeNode t1=new DefaultMutableTreeNode("dos");//节点。
   DefaultMutableTreeNode t2=new DefaultMutableTreeNode("java");//节点。
   DefaultMutableTreeNode t1_1=new DefaultMutableTreeNode("applet");
   DefaultMutableTreeNode t1_2=new DefaultMutableTreeNode("jre");
   root.add(t1);root.add(t2);
   t1.add(t1_1);t1.add(t1_2);//t1_1,t1_2成为t1的子节点。
   JTree tree =new JTree(root); //创建根为root的树。
   JScrollPane scrollpane=new JScrollPane(tree);
   con.add(scrollpane);
  }
}



25-例子32
import javax.swing.*;
import javax.swing.tree.*;import java.awt.*;
import java.awt.event.*;import javax.swing.event.*;
public class Mytree2 extends JFrame implements TreeSelectionListener
{  JTree tree=null;JTextArea text=new JTextArea(20,20);
  Mytree2()
  {Container con=getContentPane();
   DefaultMutableTreeNode root=new DefaultMutableTreeNode("同学通讯录");
   DefaultMutableTreeNode t1=new DefaultMutableTreeNode("大学同学");
   DefaultMutableTreeNode t2=new DefaultMutableTreeNode("研究生同学");
   DefaultMutableTreeNode t1_1=new DefaultMutableTreeNode("董明光");
   DefaultMutableTreeNode t1_2=new DefaultMutableTreeNode("李晓");
   DefaultMutableTreeNode t2_1=new DefaultMutableTreeNode("王光明");
   DefaultMutableTreeNode t2_2=new DefaultMutableTreeNode("代学才");
   root.add(t1);root.add(t2);
   t1.add(t1_1);t1.add(t1_2);  t2.add(t2_1);t2.add(t2_2);
   tree =new JTree(root);
   JScrollPane scrollpane=new JScrollPane(text);
   JSplitPane splitpane=new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
                            true,tree,scrollpane);
   tree.addTreeSelectionListener(this);   
   con.add(splitpane);
   addWindowListener(new WindowAdapter()
    { public void windowClosing(WindowEvent e)
      {System.exit(0);} });
   setVisible(true);setBounds(70,80,200,300);
    }
 public void valueChanged(TreeSelectionEvent e)
  { if(e.getSource()==tree)
     {DefaultMutableTreeNode node=
      (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
      if(node.isLeaf())
        { String str=node.toString();
           if(str.equals("董明光"))
             {text.setText(str+":联系电话：[phone]");}
           else if(str.equals("李晓"))
            {text.setText(str+":联系电话：[phone]");} 
           else if(str.equals("王光明"))
            {text.setText(str+":联系电话：[phone]");} 
           else if(str.equals("代学才"))
            {text.setText(str+":联系电话：[phone]");} 
        }
      else 
       {text.setText(node.getUserObject().toString());
       }
     }
  }
}
class Example32
{public static void main(String args[])
  { Mytree2 win=new Mytree2();win.pack();
 } 
}



25-例子33
import javax.swing.*;import javax.swing.tree.*;
import java.awt.*;
public class Mytree3 extends JApplet
{ public void init()
  {Container con=getContentPane();
   DefaultMutableTreeNode root=new DefaultMutableTreeNode("c:\\");//树的根节点。
   DefaultMutableTreeNode t1=new DefaultMutableTreeNode("dos");//节点。
   DefaultMutableTreeNode t2=new DefaultMutableTreeNode("java");//节点。
   DefaultMutableTreeNode t1_1=new DefaultMutableTreeNode("wps");
   DefaultMutableTreeNode t1_2=new DefaultMutableTreeNode("epg");
   DefaultMutableTreeNode t2_1=new DefaultMutableTreeNode("applet");
   DefaultMutableTreeNode t2_2=new DefaultMutableTreeNode("jre");
   root.add(t1);root.add(t2);
   t1.add(t1_1);t1.add(t1_2);
   t2.add(t2_1);t2.add(t2_2);
   JTree tree =new JTree(root); //创建根为root的树。
   DefaultTreeCellRenderer render=new  DefaultTreeCellRenderer();
   render.setLeafIcon(new ImageIcon("leaf.gif"));
   render.setBackground(Color.yellow);
   render.setClosedIcon(new ImageIcon("close.gif"));
   render.setOpenIcon(new ImageIcon("open.gif"));
   render.setTextSelectionColor(Color.red);
   render.setTextNonSelectionColor(Color.green);
   render.setFont(new Font("TimeRoman",Font.BOLD,16));
   tree.setCellRenderer(render);
   JScrollPane scrollpane=new JScrollPane(tree);
   con.add(scrollpane);
  }
}



25-例子34
import javax.swing.*;
import javax.swing.tree.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;import java.util.*;
class Classmate extends JFrame 
{  JTree tree=null; DefaultMutableTreeNode root;
   BufferedReader in; FileReader file;
  Classmate()
  {Container con=getContentPane();
    String s=null;
   try {File f=new File("通讯录.txt");
     file=new FileReader(f);
         in=new BufferedReader(file);
        }
    catch(FileNotFoundException e){}
     try{s=in.readLine();                //读取第一行并用它创建根节点。
         root=new DefaultMutableTreeNode(s);         
         }
      catch(IOException exp){}
  try
  { while((s=in.readLine())!=null&&(s.startsWith("%"))) 
     {   s=in.readLine();
         DefaultMutableTreeNode 同学种类=new DefaultMutableTreeNode(s); 
         root.add(同学种类);
           while((s=in.readLine())!=null&&!(s.startsWith("end")))
           { StringTokenizer tokenizer=new StringTokenizer(s,"#");
              String temp=tokenizer.nextToken();
              DefaultMutableTreeNode 同学种类_姓名=new DefaultMutableTreeNode(temp);
              同学种类.add(同学种类_姓名);
               while(tokenizer.hasMoreTokens())
                {同学种类_姓名.add(new DefaultMutableTreeNode(tokenizer.nextToken()));
                }
            }
      
 }       
    }    
   catch(IOException exp){}   
   tree =new JTree(root);
   JScrollPane scrollpane=new JScrollPane(tree);
   con.add(scrollpane);
   addWindowListener(new WindowAdapter()
    { public void windowClosing(WindowEvent e)
      {System.exit(0);} });
   setVisible(true);setBounds(70,80,200,300);
   }
 
}
public class Example34
{public static void main(String args[])
  { Classmate win=new Classmate();win.pack();} 
}



25-例子35

import javax.swing.*;
import javax.swing.tree.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.event.*;
import java.io.*;
 class Remember extends JFrame implements TreeSelectionListener,ActionListener
{  JTree tree=null;JTextArea text=new JTextArea(" ",20,20);int i=0;
    DefaultMutableTreeNode root;JButton b_save=new JButton("保存日志"),
    b_del=new JButton("删除日志");
   DefaultMutableTreeNode month[]=new DefaultMutableTreeNode[13];
  Remember()
  {Container con=getContentPane();
   DefaultMutableTreeNode root=new DefaultMutableTreeNode("日历记事本");
   for(i=1;i<=12;i++)
    {month[i]=new DefaultMutableTreeNode(""+i+"月");
     root.add(month[i]); 
    }
   for(i=1;i<=12;i++)
    { if(i==1||i==3||i==5||i==7||i==8||i==10||i==12)
      { for(int j=1;j<=31;j++)
        month[i].add(new DefaultMutableTreeNode(j+"日"));
      }
     else if(i==4||i==6||i==9||i==11)
      { for(int j=1;j<=30;j++)
        month[i].add(new DefaultMutableTreeNode(j+"日"));
      }
     else
      { for(int j=1;j<=28;j++)
        month[i].add(new DefaultMutableTreeNode(j+"日"));
      }
    }
   b_save.addActionListener(this); b_del.addActionListener(this);
   tree =new JTree(root);
   JPanel p=new JPanel();p.setLayout(new BorderLayout());
   JScrollPane scrollpane_1=new JScrollPane(text);
   p.add(scrollpane_1,BorderLayout.CENTER);
   JPanel p_1=new JPanel();p_1.add(b_save);p_1.add(b_del);
   p.add(p_1,BorderLayout.NORTH);
   JScrollPane scrollpane_2=new JScrollPane(tree);
   JSplitPane splitpane=new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,
                            true,scrollpane_2,p);
   tree.addTreeSelectionListener(this);   
   con.add(splitpane);
   addWindowListener(new WindowAdapter()
    { public void windowClosing(WindowEvent e)
      {System.exit(0);} });
   setVisible(true);setBounds(70,80,200,300);
  }
 public void valueChanged(TreeSelectionEvent e)
  { text.setText(" ");
    if(e.getSource()==tree)
     {DefaultMutableTreeNode node=
      (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
       if(node.isLeaf())
        { String str=node.toString();
           for(int i=0;i<=12;i++)
            {if(node.getParent()==month[i])
              {try 
               { String temp=null;
                 File f=new File(node.getParent().toString()+str+".txt");
                 FileReader file=new FileReader(f);
                 BufferedReader in=new BufferedReader(file);
                 while((temp=in.readLine())!=null)
                  text.append(temp+'\n'); 
                 file.close();in.close(); 
                }
               catch(FileNotFoundException e1){}
               catch(IOException e1){}  
               }           
            }
         }
      }
  }
 public void actionPerformed(ActionEvent e)
 {if(e.getSource()==b_save)
   {  DefaultMutableTreeNode node=
      (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
      String str=node.toString();
      if(node.isLeaf())
      {try
       { File f=new File(node.getParent().toString()+str+".txt");
         FileWriter tofile=new FileWriter(f);
         BufferedWriter out=new BufferedWriter(tofile);
         out.write(text.getText(),0,(text.getText()).length());
         out.flush();
         tofile.close();out.close(); 
       }
      catch(FileNotFoundException e1){}
       catch(IOException e1){}   
      }
   }
  else if(e.getSource()==b_del)
   {  DefaultMutableTreeNode node=
      (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
      String str=node.toString();
      if(node.isLeaf())
      {try
       { File f=new File(node.getParent().toString()+str+".txt");
         FileWriter  tofile=new FileWriter("gxy.bat");
        BufferedWriter out=new BufferedWriter(tofile);
        String temp1="del "+f.getAbsoluteFile().toString();
        out.write(temp1,0,temp1.length());
        out.newLine();
        out.flush();
        tofile.close();out.close();        
       }
       catch(IOException e1){} 
      }
     del();
   }
 }
 void del()
  {try{ Runtime ce=Runtime.getRuntime();
         ce.exec("gxy.bat");
       } 
   catch(IOException e1){} 
   }
}
public class Example35
{public static void main(String args[])
  {Remember win=new Remember();win.pack();
 } 
}