package common;

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

public class DBUtil {
	
	private Connection conn;
	private Statement stmt;
	private ResultSet result;
	
	public DBUtil() {
		
		String className="com.mysql.jdbc.Driver";//��������
		try{
			Class.forName(className);
		}catch(ClassNotFoundException e){
			e.printStackTrace();
			
			System.out.print("h");
			
		}
		
	}
	/**
	 * 
	 * @return
	 */
	
	public Connection getConn(){
		String url = "jdbc:mysql://localhost:3306/tb?characterEncoding=utf-8";
		String user = "root";
		String password = "root";
		
		try{
			conn = DriverManager.getConnection(url, user, password);
			
		} catch (SQLException e) {
			e.printStackTrace();
			
			System.out.print("执行数据库失败");
		}
		
		return conn;

		}
	
	
	public Statement getStmt(){
		try {
			if(conn == null){
				conn = this.getConn();//���û���������ݿ⣬����������
			}
			stmt = conn.createStatement();
		} catch (SQLException e) {
			e.printStackTrace();
		
			System.out.print("����Statement����ʧ��");
		}
		return stmt;
	}
	
	
	public int executeUpdate(String sql){
		int row = -1;
		try {
			if(stmt == null){
				stmt = this.getStmt();//���ô���Statement����ķ��������ֳ�����
			}
			row = stmt.executeUpdate(sql);
		} catch (SQLException e) {
			
			e.printStackTrace();
		}
		return row;
	}
	
	
	public ResultSet executeQuery(String sql){
		try {
			if(stmt == null){
				stmt = this.getStmt();//���ô���Statement����ķ��������ֳ�����
			}
			result = stmt.executeQuery(sql);
		} catch (SQLException e) {
			
			e.printStackTrace();
		}
		return result;
	}
	
	
	
	public void closeDB(){
		try {
			if(result != null){
				result.close();
				result = null;
			}
			
			if(stmt != null){
				stmt.close();
				stmt = null;
			}
			
			if(conn != null){
				conn.close();
				conn = null;
			}
		} catch (SQLException e) {
			
			e.printStackTrace();
			System.out.println("�ر����ݿ�ʧ��");
		}
		
	}

}