tabledisplay.java~2~

数据库查询结果表格输出实例

/**
 * <p>Title: 以表格显示数据库查询结果</p>
 * <p>Description: 第五章例子</p>
 * <p>Copyright: Copyright (c) 2006</p>
 * <p>Company: </p>
 * @author 苏年乐
 * @version 1.0
 */

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

public class TableDisplay extends JFrame {

   //数据库变量定义
   private Connection connection;
   private Statement statement;
   private ResultSet resultSet;
   private ResultSetMetaData rsMetaData;

   //GUI变量定义
   private JTable table;
   private JTextArea inputQuery;
   private JButton submitQuery;

   public TableDisplay()
   {
      //Form的标题
      super( "输入SQL语句，按提交按钮查看结果。" );
      //url中指定ODBC中设置的DSN名称
      String url = "jdbc:odbc:AddressBook";
      String username = "";
      String password = "";
      //加载驱动程序以连接数据库
      try {
         Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
         connection = DriverManager.getConnection(
            url, username, password );
      }
      //捕获加载驱动程序异常
      catch ( ClassNotFoundException cnfex ) {
         System.err.println(
            "装载 JDBC/ODBC 驱动程序失败。" );
         cnfex.printStackTrace();
         System.exit( 1 );  // terminate program
      }
      //捕获连接数据库异常
      catch ( SQLException sqlex ) {
         System.err.println( "无法连接数据库" );
         sqlex.printStackTrace();
         System.exit( 1 );  // terminate program
      }
      //如果数据库连接成功，则建立GUI
      //SQL语句
      String test="SELECT * FROM TblAddressBook";
      inputQuery = new JTextArea( test, 4, 30 );
      submitQuery = new JButton( "查询" );
      //Button事件
      submitQuery.addActionListener(
         new ActionListener() {
            public void actionPerformed( ActionEvent e )
            {
               getTable();
            }
         }
      );

      JPanel topPanel = new JPanel();
      topPanel.setLayout( new BorderLayout() );
      //将"输入查询"编辑框布置到 "CENTER"
      topPanel.add( new JScrollPane( inputQuery), BorderLayout.CENTER );
      //将"提交查询"按钮布置到 "SOUTH"
      topPanel.add( submitQuery, BorderLayout.SOUTH );
      table = new JTable();
      Container c = getContentPane();
      c.setLayout( new BorderLayout() );
      //将"topPanel"编辑框布置到 "NORTH"
      c.add( topPanel, BorderLayout.NORTH );
      //将"table"编辑框布置到 "CENTER"
      c.add( table, BorderLayout.CENTER );
      getTable();
      setSize( 500, 300 );
      //显示Form
      show();
   }

   private void getTable()
   {
      try {
               //执行SQL语句
         String query = inputQuery.getText();
         statement = connection.createStatement();
         resultSet = statement.executeQuery( query );
         //在表格中显示查询结果
         displayResultSet( resultSet );
      }
      catch ( SQLException sqlex ) {
         sqlex.printStackTrace();
      }
   }

   private void displayResultSet( ResultSet rs )
      throws SQLException
   {
      //定位到达第一条记录
      boolean moreRecords = rs.next();
      //如果没有记录，则提示一条消息
      if ( ! moreRecords ) {
         JOptionPane.showMessageDialog( this,
            "结果集中无记录" );
         setTitle( "无记录显示" );
         return;
      }
      Vector columnHeads = new Vector();
      Vector rows = new Vector();
      try {
         //获取字段的名称
         ResultSetMetaData rsmd = rs.getMetaData();
         for ( int i = 1; i <= rsmd.getColumnCount(); ++i )
            columnHeads.addElement( rsmd.getColumnName( i ) );
         //获取记录集
         do {
            rows.addElement( getNextRow( rs, rsmd ) );
         } while ( rs.next() );
         //在表格中显示查询结果
         table = new JTable( rows, columnHeads );
         JScrollPane scroller = new JScrollPane( table );
         Container c = getContentPane();
         c.remove(1);
         c.add( scroller, BorderLayout.CENTER );
         //刷新Table
         c.validate();
      }
      catch ( SQLException sqlex ) {
         sqlex.printStackTrace();
      }
   }


   private Vector getNextRow( ResultSet rs,
                              ResultSetMetaData rsmd )
       throws SQLException
   {
      Vector currentRow = new Vector();
      for ( int i = 1; i <= rsmd.getColumnCount(); ++i )
         currentRow.addElement( rs.getString( i ) );
      //返回一条记录
      return currentRow;
   }

   public void shutDown()
   {
      try {
               //断开数据库连接
         connection.close();
      }
      catch ( SQLException sqlex ) {
         System.err.println( "Unable to disconnect" );
         sqlex.printStackTrace();
      }
   }

   public static void main( String args[] )
   {
      final DisplayQueryResults app =
         new DisplayQueryResults();
      app.addWindowListener(
         new WindowAdapter() {
            public void windowClosing( WindowEvent e )
            {
               app.shutDown();
               System.exit( 0 );
            }
         }
      );
   }
}