这要做的优点，当改变所要连接的数据库类型时，仅仅须要改动配置文件里的内容就可以。

二、解说getXXX()方法

<span style="font-size:18px;"><span style="white-space:pre">	</span>@Test
	public void getXXXDemo() throws Exception{
		Statement st = ConnFactory.getConn().createStatement();
		String sql = "select * from book";
		ResultSet rs = st.executeQuery(sql);
		while(rs.next()){
			Integer id = rs.getInt(1);//这里的1表示数据表中的第一列，以下同理
			String name = rs.getString(2);
			//Double price = (Double)rs.getObject(3);//出异常，由于内部是採用BigDecimal来处理
			Double price = rs.getDouble(3);
			Object dateTime = rs.getObject(4);//把日期和时间作为一个总体读取出来
			System.out.println(id+","+name+","+price+","+dateTime);
			
			String strDateTime = dateTime.toString();
			System.out.println(strDateTime);
			strDateTime = rs.getDate(4)+"--"+rs.getTime(4);//日期和时间能够单独获取
			System.out.println(":::"+strDateTime);
		}
		ConnFactory.getConn().close();
	}</span>

三、解说Statement中的三个executeXXX()方法

1、executeQuery: 仅仅能运行select语句

2、executeUpdate: 能够运行insert、delete和update语句，但不能运行select

3、execute:增删改查的4种(随意)语句都能运行。该方法若运行非select语句时返回false，运行select语句时返回true，且st对象会缓存该次查询的结果。我

们可通过ResultSet rs = st.getResultSet()来获得结果集

<span style="font-size:18px;"><span style="white-space:pre">	</span>@Test
	public void executeXXXDemo() throws Exception{
		Statement st = ConnFactory.getConn().createStatement();
	    String sql = "select * from book";
		//String sql = "insert into book(name,price,pub) values('软件project',22.35,'2015-12-05 22:12:23')";
		//String sql = "update book set price=38.88 where name='软件project'";
		//String sql = "delete from book where name='软件project'";
	    //st.executeQuery(sql);
		//st.executeUpdate(sql);
		boolean boo = st.execute(sql);
		
		if(boo){
			ResultSet rs = st.getResultSet();
			while(rs.next()){
				System.out.println(rs.getObject(2));
			}
		}
	}</span>

四、数据库查询时防黑技术（预处理语句）

案例、用户登录（通过用户输入信息来拼接sql语句----非常危急）

<span style="font-size:18px;"><span style="white-space:pre">	</span>@Test//用户登录    
	public void login() throws Exception{
		Connection con = ConnFactory.getConn();
		Statement st = con.createStatement();
		Scanner sc = new Scanner(System.in);
		int id = sc.nextInt(); sc.nextLine();
		String name = sc.nextLine();
		String sql = "select count(*) from stud where id="+id+" and sname='"+name+"'";
		System.out.println("sql:"+sql);
		ResultSet rs = st.executeQuery(sql);
		rs.next();
		int a = rs.getInt(1);
		if(a<=0){
			System.out.println("登录不成功");
		}else{
			System.out.println("登录成功");
		}
		
		con.close();	   
	}</span>

况，应该用PreparedStatement来解决！

<span style="font-size:18px;"><span style="white-space:pre">	</span>@Test//用户登录     黑：1002(回车)   1' or '1'='1
	public void login2() throws Exception{
		Scanner sc = new Scanner(System.in);
		
		Connection con = ConnFactory.getConn();
		String sql = "select count(*) from stud where id=? and sname=?";//须要用户输入的地方，用占位符('?')来取代。然后在兴许通过设參来给占位符赋值
		PreparedStatement pst = con.prepareStatement(sql);
		//设置參数
		int id = sc.nextInt(); sc.nextLine();
		pst.setInt(1, id); //參数1----代表第1个占位符
		String name = sc.nextLine();
		pst.setString(2, name);//參数2
		
		ResultSet rs = pst.executeQuery();
		
		rs.next();
		int a = rs.getInt(1);
		if(a<=0){
			System.out.println("登录不成功");
		}else{
			System.out.println("登录成功");
		}
		
		con.close();	   
	}</span>

五、获取自己主动增长列（如id）

<span style="font-size:18px;"><span style="white-space:pre">	</span>@Test //演示获取自己主动增长列如id
	public void saveAuto() throws Exception{
		Connection con = ConnFactory.getConn();
		String sql = "insert into book(name,price,pub) values('JavaEE',100.8,'2013-06-12 08:30:30')";
		Statement st = con.createStatement();
		
		//st.executeUpdate(sql);
		st.executeUpdate(sql,Statement.RETURN_GENERATED_KEYS);
		ResultSet rs = st.getGeneratedKeys();//里面封装了自己主动生成的全部值
		if(rs.next()){
			int id = rs.getInt(1);//获取第1个自己主动增长列
			System.out.println("自己主动增长的id:"+id);
		}
		System.out.println("-----------------");
		
		//预处理语句
		sql =  "insert into book(name,price) values(?,?)";
		PreparedStatement pst = con.prepareStatement(sql,Statement.RETURN_GENERATED_KEYS);
		pst.setString(1, "计算机基础");
		pst.setDouble(2, 28);
		pst.executeUpdate();
		ResultSet rs2 = pst.getGeneratedKeys();//里面封装了自己主动生成的全部值
		if(rs2.next()){
			int id = rs2.getInt(1);//获取第1个自己主动增长列
			System.out.println("自己主动增长的id:"+id);
		}
	}</span>

六、演示批处理语句

public void batch() throws Exception{
		Connection con = ConnFactory.getConn();
		String sql = "insert into book(name,price,pub) values('JavaEE',100.8,'2015-06-12 08:30:30')";
		Statement st = con.createStatement();
		for(int i=0;i<10;i++){
			st.addBatch(sql);
		}
		sql = "update book set price=price*1.1 where price>100";
		st.addBatch(sql);
		int[] a = st.executeBatch();
		for(int r:a){
			System.out.println(r);//r为每条sql语句所影响的记录数
		}
	}

public void preparedBatch() throws Exception{
		Connection con = ConnFactory.getConn();
		String sql = "insert into book(name,price,pub) values(?,?,?)";
		PreparedStatement pst = con.prepareStatement(sql);
		for(int i=0;i<5;i++){
			pst.setString(1, "Java"+i);
			pst.setDouble(2, 55.85+i);
			pst.setString(3, "2016-12-10 07:07:08");
			pst.addBatch(); //pst的方式不能带參数sql
		}
		//pst.executeBatch();
		int[] a = pst.executeBatch();
		for(int r:a){
			System.out.println(r);//r为每条sql语句所影响的记录数
		}
	}