queryframe.java

java 数据库编程源代码

package multipagequery;

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

/**
 * Title:			使用多窗口查询数据库
 * Description:			教学示范
 * Copyright:			Copyright (c) 2003
 * Company:			北京师范大学计算机系
 * @author			孙一林
 * @version			1.0
 */

class queryFrame extends JFrame
{
  private JPanel contentPane;
  int recordCount = 0;
  int columnCount = 0;
  Connection connection = null;                //定义与数据库进行连接的Connection对象
  ResultSet rs = null;                         //定义数据库查询的结果集
  Statement statement = null;                  //定义查询数据库的Statement对象
  boolean lastQuery = false;                   //上次查询是否成功
  Vector vector;                               //定义存储结果集数据的数组
  String[] title;                              //定义显示数据表格的标题
  AbstractTableModel tm;                       //定义显示数据表格的抽象类
  JScrollPane scroll;                          //定义装载数据表格的容器
  JTable table;

  public queryFrame(String tableName)
  {
    enableEvents(AWTEvent.WINDOW_EVENT_MASK);
    try
    {
      frameInit(tableName);
    }
    catch(Exception ex)
    {
      ex.printStackTrace();
    }
  }

  private void frameInit(String tableName) throws Exception  //创建显示数据窗口界面
  {
    contentPane = (JPanel) this.getContentPane();
    try
    {
      Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");   //指定与数据库连接使用JDBC-ODBC桥驱动程序
      String url = "jdbc:odbc:student";                //指定数据源名
      connection = DriverManager.getConnection(url);   //与数据源建立连接
      statement = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY);  //创建Statement接口实例
      String sql = "select * from " + tableName;     //创建取出所选表中所有数据的SQL语句
      rs = statement.executeQuery(sql);                //将数据存入结果集中
      ResultSetMetaData rsData = rs.getMetaData();     //获取所选表的字段信息
      columnCount = rsData.getColumnCount();           //获取所选表的字段个数
      title = new String[columnCount];                 //将所选表的字段名称存入数组
      for(int i=1; i<=columnCount; i++)
      {
        title[i-1] = rsData.getColumnLabel(i);
      }
      while(rs.next())                                 //获取所选表的记录个数
      {
        recordCount++;
      }
    }
    catch(SQLException ex){                          //捕捉异常
      System.out.println("\nERROR:----- SQLException -----\n");
      while (ex != null) {
        System.out.println("Message:   " + ex.getMessage());
        System.out.println("SQLState:  " + ex.getSQLState());
        System.out.println("ErrorCode: " + ex.getErrorCode());
        ex = ex.getNextException();
      }
    }
    catch(Exception ex ) {
      ex.printStackTrace();
    }
    this.setTitle("显示" + tableName + "表中的数据");
    this.setSize(new Dimension(columnCount*80+50, recordCount*20+50));//通过数据行数及列数定义窗口大小
    vector = new Vector();
    tm = new AbstractTableModel() {                  //初始化显示数据的表格
      public int getColumnCount() {
        return title.length;
      }
      public int getRowCount() {
        return vector.size();
      }
      public Object getValueAt(int row, int column) {
        if(!vector.isEmpty())
        {
          return ((Vector)vector.elementAt(row)).elementAt(column);
        }
        else
        {
          return null;
        }
      }
      public void setValueAt(Object value, int row, int column)
      {

      }
      public String getColumnName(int column)
      {
        return title[column];
      }
      public Class getColumnClass(int c)
      {
        return getValueAt(0,c).getClass();
      }
      public boolean isCellEditable(int row, int column)
      {
        return false;
      }
    };
    table = new JTable(tm);
    table.setToolTipText("Display Query Result");
    table.setAutoResizeMode(table.AUTO_RESIZE_ALL_COLUMNS);
    table.setCellSelectionEnabled(false);
    table.setShowHorizontalLines(true);
    table.setShowVerticalLines(true);
    scroll = new JScrollPane(table);
    scroll.setBounds(new Rectangle(10, 10, 10+columnCount*80, 10+recordCount*20));//通过数据行数及列数定义表格大小
    contentPane.add(scroll,null);
    vector.removeAllElements();
    tm.fireTableStructureChanged();                  //刷新表格显示结果集中的数据
    rs.beforeFirst();
    while(rs.next())
    {
      Vector rec_vector = new Vector();
      for(int i=1; i<=columnCount; i++)
      {
        rec_vector.addElement(rs.getString(i));
      }
      vector.addElement(rec_vector);
    }
    tm.fireTableStructureChanged();
  }

  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      try
      {
        statement.close();                      //关闭Statement接口实例
        connection.close();                   //关闭Connection接口实例
      }
      catch(Exception ex)
      {
        ex.printStackTrace();
      }
      this.dispose();
    }
  }
}