public class TestJDBC {
	public static void main(String[] args) throws ClassNotFoundException, SQLException {
		//1、注冊驅動
		//(1)方式一：Class.forName("驅動類的全名稱")
		Class.forName("com.mysql.cj.jdbc.Driver");
//		(2)創(chuàng)建驅動類的對象
//		new com.mysql.cj.jdbc.Driver();//硬編碼
		//(3)通過DriverManager注冊驅動
//		DriverManager.registerDriver(new com.mysql.cj.jdbc.Driver());//硬編碼
		//2、獲取連接，連接數(shù)據(jù)庫
        //TCP/IP協(xié)議編程，需要服務器的IP地址和端口號
		//mysql的url格式：jdbc協(xié)議:子協(xié)議://主機名:端口號/要連接的數(shù)據(jù)庫名
		String url = "jdbc:mysql://localhost:3306/test?serverTimezone=UTC";//其中test是數(shù)據(jù)庫名;serverTimezone是時區(qū)不設置可能報錯
		String user = "root";
		String password = "123456";
		Connection conn = DriverManager.getConnection(url, user, password);
		//3、執(zhí)行sql
		//添加一個部門到數(shù)據(jù)庫的t_department表中
		//(1)編寫sql
		String sql = "insert into t_department values(null,'計算部2','計算鈔票2')";
		/*
		 * 回憶：	TCP/IP程序時
		 * Socket代表連接
		 * socket.getOutputStream()來發(fā)送數(shù)據(jù)，
		 * socket.getInputStream()來接收數(shù)據(jù)
		 * 
		 * 可以把Connection比喻成Socket
		 *    把Statement比喻成OutputStream
		 */
		//(2)獲取Statement對象
		Statement st = conn.createStatement();
		//(3)執(zhí)行sql
		int len = st.executeUpdate(sql);
		//(4)處理結果
		System.out.println(len>0?"成功":"失敗");
		//4、關閉
		st.close();
		conn.close();
	}
}

public class TestSelect {
	public static void main(String[] args) throws Exception{
		// 1、注冊驅動
		Class.forName("com.mysql.cj.jdbc.Driver");
		// 2、連接數(shù)據(jù)庫
		Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?serverTimezone=UTC", "root", "123456");
		// 3、執(zhí)行sql
		String sql = "SELECT * FROM t_department";
		Statement st = conn.createStatement();
		ResultSet rs = st.executeQuery(sql);//ResultSet看成InputStream
		while(rs.next()){//next()表示是否還有下一行
			Object did = rs.getObject(1);//獲取第n列的值
			Object dname = rs.getObject(2);
			Object desc = rs.getObject(3);
			/*
			int did = rs.getInt("did");//也可以根據(jù)列名稱，并且可以按照數(shù)據(jù)類型獲取
			String dname = rs.getString("dname");
			String desc = rs.getString("description");
			 */
			System.out.println(did +"\t" + dname + "\t"+ desc);
		}
		// 4、關閉
		rs.close();
		st.close();
		conn.close();
	}
}

	String sql = "insert into t_employee(ename,tel,gender,salary) values('" + ename + "','" + tel + "','" + gender + "'," + salary +")";
		Statement st = conn.createStatement();
		int len = st.executeUpdate(sql);

	String sql = "SELECT * FROM t_employee where ename='" + ename + "'";
		//如果我此時從鍵盤輸入ename值的時候，輸入：張三' or '1'= '1
		//結果會把所有數(shù)據(jù)都查詢出來
		Statement st = conn.createStatement();
		ResultSet rs = st.executeQuery(sql);

String sql = "insert into user(username,photo) values('chailinyan', 圖片字節(jié)流)";
//此時photo是blob類型的數(shù)據(jù)時，無法在sql中直接拼接

		String sql = "insert into t_employee(ename,tel,gender,salary) values(?,?,?,?)";
		PreparedStatement pst = conn.prepareStatement(sql);//這里要傳帶？的sql，然后mysql端就會對這個sql進行預編譯
		//根據(jù)字段來設置？的具體值
		/*pst.setString(1, ename);
		pst.setString(2, tel);
		pst.setString(3, gender);
		pst.setDouble(4, salary);*/
		pst.setObject(1, ename);
		pst.setObject(2, tel);
		pst.setObject(3, gender);
		pst.setObject(4, salary);
		int len = pst.executeUpdate();//此處不能傳sql
		System.out.println(len);

String sql = "SELECT * FROM t_employee where ename=?";
		//即使輸入'張三' or '1'= '1'也沒問題
		PreparedStatement pst = conn.prepareStatement(sql);
		//中間加入設置？的值
		pst.setObject(1, ename);
		ResultSet rs = pst.executeQuery();

		String sql = "insert into user(username,photo) values(?,?)";
		PreparedStatement pst = conn.prepareStatement(sql);
		//設置？的值
		pst.setObject(1, "xiaoyu");
		FileInputStream fis = new FileInputStream("D:/QMDownload/img/15.jpg");
		pst.setBlob(2, fis);
		int len = pst.executeUpdate();
		System.out.println(len>0?"成功":"失敗");