javaweb连接mysql的两种方法

一、直接连接，不封装到工具类中，主要步骤：

先导包:mysql-connector-java-5.0.8-bin.jar(点击跳转到下载界面),放在WebRoot/WEB-INF/lib/下

  1.加载驱动//com.MySQL.jdbc.Driver

  2.获取连接 Connection对象

  3.获取用于向数据库发送SQL的Statement对象
  
  4.执行sql,获取数据，解析数据
  
  5.关闭连接，释放资源

               /* 协议：子协议://主机:端口/数据库名 */
 String url = "jdbc:mysql://localhost:3306/jdbctest";

 // mysql数据库的用户名与密码，安装时自己设置，一般默认为root
 String user = "root";
 String password = "root";

 Connection connection = null;
 Statement statement = null;
 ResultSet resultSet = null;
 try {
     // 1.加载驱动//com.mysql.jdbc.Driver
     /*
      * DriverManager.registerDriver(new
      * Driver());用这种方法会加载两次驱动，也就是说会创建两个drive对象
      */
     Class.forName("com.mysql.jdbc.Driver");
     // 2.获取连接
     connection = DriverManager.getConnection(url, user, password);

     // 3.获取用于向数据库发送SQL的Statement对象
     statement = connection.createStatement();

     // 4.执行sql,获取数据
     resultSet = statement.executeQuery("SELECT * FROM users;");

     // 解析数据
     while (resultSet.next()) {
         int id = resultSet.getInt("id");
         String name = resultSet.getString("name");
         String psd = resultSet.getString("password");
         String email = resultSet.getString("email");
         String birthday = resultSet.getString("birthday");

         System.out.println(id + " " + name + " " + psd + " " + email
                 + " " + birthday);
     }
 } catch (ClassNotFoundException e) {
     e.printStackTrace();
 } catch (SQLException e) {
     e.printStackTrace();
 } finally {

                       //5.关闭连接，释放资源
     if (resultSet != null) {
         try {
             resultSet.close();
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
         resultSet = null;
     }

     if (statement != null) {
         try {
             statement.close();
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
         statement = null;
     }

     if (connection != null) {
         try {
             connection.close();
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
         connection = null;
     }
 }