Java的数据库连接

王朝java/jsp·作者佚名  2008-05-31
窄屏简体版  字體: |||超大  

java的数据库连接终于做好了,虽然功能是简单了点,不过我会推出复杂一点的程序,可能以后推出的只用鼠标就可以完成绝大部分的数据库操作,好了,这次的数据库还是用的和那个非常小的数据库治理系统(jsp)一样的MySQL web_data 的数据库。

图示如下:

代码如下:

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import java.sql.*;

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

import java.util.*;

public class inensshow extends JFrame {

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 inensshow()

{

//Form的标题

super( "输入SQL语句,按查询按钮查看结果。" );

String url = "jdbc:mysql://localhost:3306/web";

String username = "inens";

String passWord = "inens";

//加载驱动程序以连接数据库

try {

Class.forName( "org.gjt.mm.mysql.Driver" );

connection = DriverManager.getConnection(

url, username, password );

}

//捕捉加载驱动程序异常

catch ( ClassNotFoundException cnfex ) {

System.err.println(

"装载 JDBC/ODBC 驱动程序失败。" );

cnfex.printStackTrace();

System.exit( 1 ); // terminate program

}

//捕捉连接数据库异常

catch ( SQLException sqlex ) {

System.err.println( "无法连接数据库" );

sqlex.printStackTrace();

System.exit( 1 ); // terminate program

}

//假如数据库连接成功,则建立GUI

//SQL语句

String test="SELECT * FROM data";

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();

//假如没有记录,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 inensshow app =

new inensshow();

app.addWindowListener(

new WindowAdapter() {

public void windowClosing( WindowEvent e )

{

app.shutDown();

System.exit( 0 );

}

}

);

}

}

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这次在WIN98中就不好使了。因为Mysql的驱动程序没有也没能加入到CLASSPATH 当中,但是JSP却可以使用(JSP的98驱动加载详见Jsp与Mysql连接查错文章),所以这次我是在XPServer中测试的。

 
 
 
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