example5_9_1.java

书中的例题

//　JTable表格应用
 import javax.swing.JTable;
 import javax.swing.table.AbstractTableModel;
 import javax.swing.JScrollPane;
 import javax.swing.JFrame;
 import javax.swing.SwingUtilities;
 import javax.swing.JOptionPane;
 import java.awt.*;
 import java.awt.event.*;
 public class TableDemo extends JFrame
  {
     //实现构造方法
    public TableDemo() 
    { 
     //首先调用父类JFrame的构造方法生成一个窗口
     super("员工档案表"); 
     //myModel存放表格的数据
     MyTableModel myModel = new MyTableModel();
     //表格对象table的数据来源是myModel对象
     JTable table = new JTable(myModel);
     //表格的显示尺寸 
     table.setPreferredScrollableViewportSize(new Dimension(500,70));
     //产生一个带滚动条的面板 
     JScrollPane scrollPane = new JScrollPane(table);
     //将带滚动条的面板添加入窗口中
     getContentPane().add(scrollPane, BorderLayout.CENTER);
     addWindowListener(new WindowAdapter() {//注册窗口监听器
      public void windowClosing(WindowEvent e) {
         System.exit(0);
        }
      });
    }
  }
  
    //把要显示在表格中的数据存入字符串数组和Object数组中
  class MyTableModel extends AbstractTableModel
   {
     private boolean DEBUG = true;
      //表格中第一行所要显示的内容存放在字符串数组columnNames中
     final String[] columnNames = {"姓名","职务","电话",
                                   "月薪","婚否"};
     //表格中各行的内容保存在二维数组data中
     final Object[][] data = {
      {"李强", "经理",  "059568790231", 
        new Integer(5000), new Boolean(false)},
      {"吴虹", "秘书",  "059569785321", 
        new Integer(3500), new Boolean(true)},
      {"陈卫东", "主管","059565498732",
        new Integer(4500), new Boolean(false)},
      {"欧阳建", "保安","059562796879",
        new Integer(2000), new Boolean(true)},
      {"施乐乐", "销售","059563541298",
        new Integer(4000), new Boolean(false)}
     };
     /*下述方法是重写AbstractTableModel中的方法,
      *其主要用途是被JTable对象调用，以便在表格中正确的显示出来。
      *程序员必须根据采用的数据类型加以恰当实现。 
     */
     //获得列的数目
      public int getColumnCount()
       {
        return columnNames.length;
       }
       //获得行的数目
      public int getRowCount() 
      {
        return data.length;
      }
     //获得某列的名字，而目前各列的名字保存在字符串数组columnNames中
     public String getColumnName(int col)
      {
        return columnNames[col];
      }
     //获得某行某列的数据，而数据保存在对象数组data中
     public Object getValueAt(int row, int col)
      {
       return data[row][col];
      }
     //判断每个单元格的类型
     public Class getColumnClass(int c) 
     {
       return getValueAt(0, c).getClass();
      }
     //将表格声明为可编辑的
     public boolean isCellEditable(int row, int col)
      {
       if (col < 2) { return false; }
       else { return true; }
      }
      //改变某个数据的值
     public void setValueAt(Object value, int row, int col)
      {
        if (DEBUG)
         {
           System.out.println("Setting value at "+row+","+col
             +" to "+value+" (an instance of "+value.getClass()+")");
         }
       if (data[0][col] instanceof Integer 
            && !(value instanceof Integer))
        { 
         try 
          {
             data[row][col] = new Integer(value.toString());
             fireTableCellUpdated(row, col);
          }
         catch (NumberFormatException e)
          {
          	TableDemo table=new TableDemo();
             JOptionPane.showMessageDialog(table,
                 "The \"" + getColumnName(col)
                 + "\" column accepts only integer values.");
          }
        } else {
                   data[row][col] = value;
                   fireTableCellUpdated(row, col);
                }
       if (DEBUG) 
       {
          System.out.println("New value of data:");
          printDebugData();
       }
      }
      private void printDebugData() 
      {
        int numRows = getRowCount();
        int numCols = getColumnCount();
        for (int i=0; i < numRows; i++) 
        {
          System.out.print(" row " + i + ":");
          for (int j=0; j < numCols; j++) 
          {
            System.out.print(" " + data[i][j]);
          }
          System.out.println();
        }
        System.out.println("--------------------------");
      }
    } 
   //主类
  public class Example5_9_1
  {
    public static void main(String[] args)
     {
          TableDemo frame = new TableDemo();
          frame.pack();
          frame.setVisible(true);
     }
  }