queryframe.java

JAVA数据库编程实例随书源码 JAVA数据库编程实例随书源码

package query;
import com.borland.jbcl.layout.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;
import javax.swing.*;

/**
   * Title:				查询数据库程序
   * 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 QueryFrame extends JFrame {
  private JPanel contentPane;
  private XYLayout xYLayout1 = new XYLayout(); // 构造XYLayout布局管理器
  private Button queryButton = new Button();   // 创建按钮组件

  Connection connection = null;                // 定义与数据库进行连接的Connection对象
  ResultSet rSet = 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

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

  private void jbInit() throws Exception  {
    contentPane = (JPanel) this.getContentPane();
    queryButton.setLabel("查询");                                          // 初始化组件
    queryButton.addActionListener(new java.awt.event.ActionListener() {   // 设置queryButton按钮监听器
      public void actionPerformed(ActionEvent e) {
        queryButton_actionPerformed(e);
      }
    });
    contentPane.setLayout(xYLayout1);
    this.setSize(new Dimension(400, 300));
    this.setTitle("查询数据库");
    contentPane.add(queryButton,  new XYConstraints(154, 171, 92, 34));
  }

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

  void queryButton_actionPerformed(ActionEvent e) {         // 处理queryButton的ActionEvent
    try {
      Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");        // 实例化JDBC-ODBC桥的驱动
      String url = "jdbc:odbc:TestDbStu";                   // 设置连接字符串
      connection = DriverManager.getConnection(url);        // 连接数据库
      statement = connection.createStatement();             // 创建Statement接口对象
      String sql = "select * from studentbase";
      rSet = statement.executeQuery(sql);                   // 执行查询语句
      ResultSetMetaData data = rSet.getMetaData();          // 定义ResultSetMetaData对象data
      int col = data.getColumnCount();                      // 获取列数
      for (int i=1; i<=col; i++) {                          // 打印列名
        if (i<col) {
        System.out.print(data.getColumnName(i) + "  ");
        }
        else {
        System.out.println(data.getColumnName(i));
        }
      }
      while(rSet.next()) {                                  // 打印数据
        for (int i=1; i<=col; i++) {
          if (i<col) {
          System.out.print(rSet.getString(i) + "  ");
          }
          else {
          System.out.println(rSet.getString(i));
          }
        }
      }
      rSet.close();                                         // 关闭结果集
    }
    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());
      }
    }
  }
}