resultsettable.java

corejava的源程序内有好多的源代码

/**
   @version 1.01 2001-07-18
   @author Cay Horstmann
*/

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.sql.*;
import java.util.*;
import javax.swing.*;
import javax.swing.table.*;

/**
   This program shows how to display the result of a 
   database query in a table.
*/
public class ResultSetTable
{  
   public static void main(String[] args)
   {  
      JFrame frame = new ResultSetFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.show();
   }
}

/**
   This frame contains a combo box to select a database table
   and a table to show the data stored in the table
*/
class ResultSetFrame extends JFrame
{  
   public ResultSetFrame()
   {  
      setTitle("ResultSet");
      setSize(WIDTH, HEIGHT);

      /* find all tables in the database and add them to
         a combo box
      */

      Container contentPane = getContentPane();
      tableNames = new JComboBox();
      tableNames.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent evt)
            {
               try
               {  
                  if (scrollPane != null)
                     getContentPane().remove(scrollPane);
                  String tableName
                     = (String)tableNames.getSelectedItem();
                  if (rs != null) rs.close();
                  String query = "SELECT * FROM " + tableName;
                  rs = stat.executeQuery(query);
                  if (scrolling)
                     model 
                        = new ScrollingResultSetTableModel(rs);
                  else
                     model = new CachingResultSetTableModel(rs);

                  JTable table = new JTable(model);
                  scrollPane = new JScrollPane(table);
                  getContentPane().add(scrollPane, 
                     BorderLayout.CENTER);
                  pack();
                  doLayout();
               }            
               catch(SQLException e)
               {  
                  e.printStackTrace();
               }
            }
         });
      JPanel p = new JPanel();
      p.add(tableNames);
      contentPane.add(p, BorderLayout.NORTH);

      try
      {  
         conn = getConnection();
         DatabaseMetaData meta = conn.getMetaData();
         if (meta.supportsResultSetType(
            ResultSet.TYPE_SCROLL_INSENSITIVE))
         {
            scrolling = true;
            stat = conn.createStatement(
               ResultSet.TYPE_SCROLL_INSENSITIVE,
               ResultSet.CONCUR_READ_ONLY);
         }
         else
         {
            stat = conn.createStatement();
            scrolling = false;
         }
         ResultSet tables = meta.getTables(null, null, null,
            new String[] { "TABLE" });
         while (tables.next())
            tableNames.addItem(tables.getString(3));
         tables.close();
      }
      catch(IOException e)
      {  
         e.printStackTrace();
      }
      catch(SQLException e)
      {  
         e.printStackTrace();
      }

      addWindowListener(new
         WindowAdapter()
         {
            public void windowClosing(WindowEvent event)
            {
               try
               {
                  conn.close();
               }
               catch (SQLException e)
               {
                  e.printStackTrace();
               }              
            }
         });
   }

   /**
      Gets a connection from the properties specified in
      the file database.properties.
      @return the database connection
    */
   public static Connection getConnection()
      throws SQLException, IOException
   {  
      Properties props = new Properties();
      FileInputStream in 
         = new FileInputStream("database.properties");
      props.load(in);
      in.close();

      String drivers = props.getProperty("jdbc.drivers");
      if (drivers != null)
         System.setProperty("jdbc.drivers", drivers);
      String url = props.getProperty("jdbc.url");
      String username = props.getProperty("jdbc.username");
      String password = props.getProperty("jdbc.password");

      return
         DriverManager.getConnection(url, username, password);
   }

   private JScrollPane scrollPane;
   private ResultSetTableModel model;
   private JComboBox tableNames;
   private ResultSet rs;
   private Connection conn;
   private Statement stat;
   private boolean scrolling;

   private static final int WIDTH = 400;
   private static final int HEIGHT = 300;
}

/** 
   This class is the superclass for the scrolling and the
   caching result set table model. It stores the result set
   and its metadata.
*/
abstract class ResultSetTableModel extends AbstractTableModel
{  
   /**
      Constructs the table model.
      @param aResultSet the result set to display.
   */
   public ResultSetTableModel(ResultSet aResultSet)
   {  
      rs = aResultSet;
      try
      {  
         rsmd = rs.getMetaData();
      }
      catch(SQLException e)
      {  
         e.printStackTrace();
      }
   }

   public String getColumnName(int c)
   {  
      try
      {  
         return rsmd.getColumnName(c + 1);
      }
      catch(SQLException e)
      {  
         e.printStackTrace();
         return "";
      }
   }

   public int getColumnCount()
   {  
      try
      {  
         return rsmd.getColumnCount();
      }
      catch(SQLException e)
      {  
         e.printStackTrace();
         return 0;
      }
   }

   /**
      Gets the result set that this model exposes.
      @return the result set
   */
   protected ResultSet getResultSet()
   {  
      return rs;
   }

   private ResultSet rs;
   private ResultSetMetaData rsmd;
}

/**
   This class uses a scrolling cursor, a JDBC 2 feature,
   to locate result set elements.
*/
class ScrollingResultSetTableModel extends ResultSetTableModel
{  
   /**
      Constructs the table model.
      @param aResultSet the result set to display.
   */
   public ScrollingResultSetTableModel(ResultSet aResultSet)
   {  
      super(aResultSet);
   }

   public Object getValueAt(int r, int c)
   {  
      try
      {  
         ResultSet rs = getResultSet();
         rs.absolute(r + 1);
         return rs.getObject(c + 1);
      }
      catch(SQLException e)
      {  
         e.printStackTrace();
         return null;
      }
   }

   public int getRowCount()
   {  
      try
      {  
         ResultSet rs = getResultSet();
         rs.last();
         return rs.getRow();
      }
      catch(SQLException e)
      {  
         e.printStackTrace();
         return 0;
      }
   }
}

/* 
   This class caches the result set data; it can be used
   if scrolling cursors are not supported
*/
class CachingResultSetTableModel extends ResultSetTableModel
{  
   public CachingResultSetTableModel(ResultSet aResultSet)
   {  
      super(aResultSet);
      try
      {  
         cache = new ArrayList();
         int cols = getColumnCount();
         ResultSet rs = getResultSet();

         /* place all data in an array list of Object[] arrays
            We don't use an Object[][] because we don't know
            how many rows are in the result set
         */

         while (rs.next())
         {  
            Object[] row = new Object[cols];
            for (int j = 0; j < row.length; j++)
               row[j] = rs.getObject(j + 1);
            cache.add(row);
         }
      }
      catch(SQLException e)
      {  
         System.out.println("Error " + e);
      }
   }

   public Object getValueAt(int r, int c)
   {  
      if (r < cache.size())
         return ((Object[])cache.get(r))[c];
      else
         return null;
   }

   public int getRowCount()
   {  
      return cache.size();
   }

   private ArrayList cache;
}