JDBC连接数据库

数据库连接池，获得connection
1.

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

/**
 * Title:
 * Description:
 * @version 
 */
public class ProxoolConnect {

	//连接数据库1
	public static Connection getConnection() throws SQLException
	{
		return DriverManager.getConnection("proxool.bbs");
	}
	//连接数据库2
	public static Connection getConnection2() throws SQLException
	{
		return DriverManager.getConnection("proxool.news");
	}
	/**
	 * 
	 */
	private ProxoolConnect() {
	}
	
}

2.

import java.sql.Connection;
import java.sql.SQLException;

import javax.naming.*;
import javax.sql.DataSource;

public class DatabaseConnection {
	public static Connection getConnection() throws SQLException,NamingException
	{
		try
		{
			Context initCtx = new InitialContext();//初始化上下文环境
            		DataSource ds = (DataSource)initCtx.lookup("java:comp/env/jdbc/boda"); 
			return ds.getConnection();
		}
		catch(SQLException e)
		{
			throw e;
		}
		catch(NamingException e)
		{
			throw e;
		}
		
	}
}

第二步，使用连接池，封装connection

/**
 * Title:
 * Description:
 * Copyright:
 * Company: 
 * 
 * @author 	
 * @version 1.0
 */

import java.sql.Connection;
import java.sql.Date;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;


public class DBPoolConnect {
	private Connection conn = null;

	private Statement stmt = null;

	private PreparedStatement prepstmt = null;

	void init() throws SQLException {
		conn = ProxoolConnect.getConnection();
	}

	/**
	 * ������ݿ��l�Ӻͷ�����
	 */
	public DBPoolConnect() throws Exception {
		init();
		stmt = conn.createStatement();
	}

	public DBPoolConnect(int resultSetType, int resultSetConcurrency)
			throws Exception {
		init();
		stmt = conn.createStatement(resultSetType, resultSetConcurrency);
	}

	/**
	 * ������ݿ��l�Ӻͷ����� Ԥ����SQL���
	 * 
	 * @param sql
	 *            SQL���
	 */
	public DBPoolConnect(String sql) throws Exception {
		init();
		this.prepareStatement(sql);
	}

	public DBPoolConnect(String sql, int resultSetType, int resultSetConcurrency)
			throws Exception {
		init();
		this.prepareStatement(sql, resultSetType, resultSetConcurrency);
	}

	/**
	 * ����l��
	 * 
	 * @return Connection l��
	 */
	public Connection getConnection() {
		return conn;
	}

	/**
	 * PreparedStatement
	 * 
	 * @return sql Ԥ��SQL���
	 */
	public void prepareStatement(String sql) throws SQLException {
		prepstmt = conn.prepareStatement(sql);
	}

	public void prepareStatement(String sql, int resultSetType,
			int resultSetConcurrency) throws SQLException {
		prepstmt = conn.prepareStatement(sql, resultSetType,
				resultSetConcurrency);
	}

	/**
	 * ���ö�Ӧֵ
	 * 
	 * @param index
	 *            ��������
	 * @param value
	 *            ��Ӧֵ
	 */
	public void setString(int index, String value) throws SQLException {
		prepstmt.setString(index, value);
	}

	public void setInt(int index, int value) throws SQLException {
		prepstmt.setInt(index, value);
	}

	public void setBoolean(int index, boolean value) throws SQLException {
		prepstmt.setBoolean(index, value);
	}

	public void setDate(int index, Date value) throws SQLException {
		prepstmt.setDate(index, value);
	}

	public void setLong(int index, long value) throws SQLException {
		prepstmt.setLong(index, value);
	}

	public void setFloat(int index, float value) throws SQLException {
		prepstmt.setFloat(index, value);
	}

	public void setBytes(int index, byte[] value) throws SQLException {
		prepstmt.setBytes(index, value);
	}

	public void clearParameters() throws SQLException {
		prepstmt.clearParameters();
		prepstmt = null;
	}

	/**
	 * ����Ԥ��״̬
	 */
	public PreparedStatement getPreparedStatement() {
		return prepstmt;
	}

	/**
	 * ����״̬
	 * 
	 * @return Statement ״̬
	 */
	public Statement getStatement() {
		return stmt;
	}

	/**
	 * ִ��SQL��䷵���ֶμ�
	 * 
	 * @param sql
	 *            SQL���
	 * @return ResultSet �ֶμ�
	 */
	public ResultSet executeQuery(String sql) throws SQLException {
		if (stmt != null) {
			return stmt.executeQuery(sql);
		} else
			return null;
	}

	public ResultSet executeQuery() throws SQLException {
		if (prepstmt != null) {
			return prepstmt.executeQuery();
		} else
			return null;
	}

	/**
	 * ִ��SQL���
	 * 
	 * @param sql
	 *            SQL���
	 */
	public void executeUpdate(String sql) throws SQLException {
		if (stmt != null)
			stmt.executeUpdate(sql);
	}

	public void executeUpdate() throws SQLException {
		if (prepstmt != null)
			prepstmt.executeUpdate();
	}
	
	public int executeUpdate2() throws SQLException {
		if (prepstmt != null)
			return prepstmt.executeUpdate();
		return 0;
	}

	/**
	 * �ر�l��
	 */
	public void close() throws Exception {
		if (stmt != null) {
			stmt.close();
			stmt = null;
		}
		if (prepstmt != null) {
			prepstmt.close();
			prepstmt = null;
		}
		if (conn != null) {
			conn.close();
			conn=null;
		}

	}
}