import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.List;
import java.util.Properties;
 
public abstract class BaseDAO {
 
	protected Connection conn;
	protected static String driverClass;
	protected static String user;
	protected static String url;
	protected static String password;
 
	static {
		//从数据库配置文件导入配置参数
		Properties p = new Properties();
		try {
			p.load(BaseDAO.class.getResourceAsStream("/dbconfig.properties"));
		} catch (IOException e1) {
			e1.printStackTrace();
		}
		driverClass = p.getProperty("driverClass");
		user = p.getProperty("user");
		url = p.getProperty("url");
		password = p.getProperty("password");
		//加载驱动类
		try {
			Class.forName("com.mysql.jdbc.Driver");
		} catch (ClassNotFoundException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	public BaseDAO(){
		openConnection();
	}
 
	/**
	 * 开启连接
	 */
	protected void openConnection(){
		try {
			conn = DriverManager.getConnection(url,user,password);
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	/**
	 * 关闭连接
	 */
	public void closeConnection(){
		if(conn!=null){
			try {
				conn.close();
			} catch (SQLException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
 
	}
 
	protected void executeUpdate(String sql){
		Statement stm = null;
		try {
			stm = conn.createStatement();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		try {
			stm.execute(sql);
		} catch (SQLException e) {
			e.printStackTrace();
		}
 
	}
	protected ResultSet executeQuery(String sql){
		Statement stm = null;
		try {
			stm = conn.createStatement();
		} catch (SQLException e) {
			e.printStackTrace();
		}
		ResultSet rs = null;
		try {
			rs = stm.executeQuery(sql);
		} catch (SQLException e1) {
			e1.printStackTrace();
		}
		return rs;
	}
 
	@SuppressWarnings("unchecked")
	protected abstract List resultSetToList(ResultSet rs);
 
}