querywithviewframe.java

Java数据库编程实例（5）

package querywithview;

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

/**
 * Title:			使用视图查询数据库纪录
 * 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
 */

public class queryWithViewFrame extends JFrame {
  JPanel contentPane;
  Button queryButton = new Button();
  Button createButton = new Button();
  String[] title = {"学号", "姓名", "年龄", "性别", "系名"};   //定义显示数据表格的标题
  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
  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

  public queryWithViewFrame() {
    enableEvents(AWTEvent.WINDOW_EVENT_MASK);
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }

  private void jbInit() throws Exception  {          //初始化用户界面
    contentPane = (JPanel) this.getContentPane();
    queryButton.setLabel("使用视图查询");
    queryButton.setBounds(new Rectangle(225, 256, 127, 32));
    queryButton.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        queryButton_actionPerformed(e);
      }
    });
    contentPane.setLayout(null);
    this.setSize(new Dimension(425, 332));
    this.setTitle("使用视图查询数据库纪录");
    createButton.setLabel("创建视图");
    createButton.setBounds(new Rectangle(69, 256, 127, 32));
    createButton.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        createButton_actionPerformed(e);
      }
    });
    contentPane.add(queryButton, null);
    contentPane.add(createButton, null);
  }

  void initTable() {                           //初始化显示数据集结果的表格
    JTable table;
    vector = new Vector();
    tm = new AbstractTableModel() {            //实现表格抽象类的接口
      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_SUBSEQUENT_COLUMNS);
    table.setCellSelectionEnabled(false);
    table.setShowHorizontalLines(true);
    table.setShowVerticalLines(true);
    scroll = new JScrollPane(table);
    scroll.setBounds(10,10,400,200);
    contentPane.add(scroll,null);
  }

  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      System.exit(0);
    }
  }

  void createButton_actionPerformed(ActionEvent e) {
    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_UPDATABLE);  //创建Statement接口实例
      String sql = "create view studentView as select * from studentbase";      //创建关于studentbase表的视图的SQL语句
      statement.executeUpdate(sql);                    //创建视图
      JOptionPane msg = new JOptionPane();
      JOptionPane.showMessageDialog(this, "创建视图成功", "创建视图成功！", 1);
    }
    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();
    }
    finally {
      try {
        if(statement != null)
        {
          statement.close();                      //关闭Statement接口实例
        }
        if(connection != null)
        {
          connection.close();                   //关闭Connection接口实例
        }
      }
      catch (SQLException ex)  {
        System.out.println("\nERROR:----- SQLException -----\n");
        System.out.println("Message:   " + ex.getMessage());
        System.out.println("SQLState:  " + ex.getSQLState());
        System.out.println("ErrorCode: " + ex.getErrorCode());
      }
    }
  }

  void queryButton_actionPerformed(ActionEvent e) {
    if(lastQuery)                               //若上次查询成功，则首先清除上次查询的表格
    {
      scroll.setVisible(false);
      contentPane.remove(scroll);
    }
    initTable();                               //初始化新的表格
    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 studentView";        //创建取出studentView视图中所有数据的SQL语句
      rs = statement.executeQuery(sql);                //将数据存入结果集中
      vector.removeAllElements();
      tm.fireTableStructureChanged();                  //刷新表格显示结果集中的数据
      while(rs.next())
      {
        Vector rec_vector = new Vector();
        rec_vector.addElement(String.valueOf(rs.getInt("学号")));
        rec_vector.addElement(rs.getString("姓名"));
        rec_vector.addElement(String.valueOf(rs.getInt("年龄")));
        rec_vector.addElement(String.valueOf(rs.getString("性别")));
        rec_vector.addElement(String.valueOf(rs.getString("系名")));
        vector.addElement(rec_vector);
      }
      tm.fireTableStructureChanged();
      lastQuery = true;                              //数据库查询操作成功
    }
    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();
    }
    finally {
      try {
        if(statement != null)
        {
          statement.close();                      //关闭Statement接口实例
        }
        if(connection != null)
        {
          connection.close();                   //关闭Connection接口实例
        }
      }
      catch (SQLException ex)  {
        System.out.println("\nERROR:----- SQLException -----\n");
        System.out.println("Message:   " + ex.getMessage());
        System.out.println("SQLState:  " + ex.getSQLState());
        System.out.println("ErrorCode: " + ex.getErrorCode());
      }
    }
  }
}