一个通过Java连接MySQL数据库的代码

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 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();

//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 rsrsmd = 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 );
}
}
);
}
}