理论上讲，android不应该直接连接数据库的，但是处于业务需要，且自己局域网使用，不存在泄漏问题，所以就尝试了android直接连接mysql数据库
首先，需要网络连接权限，这就不说了，然后添加mysql连接依赖包：

compile 'mysql:mysql-connector-java:5.1.18'

最后下面这段代码即可连接成功,记得在异步线程执行。

private void connect() {
       Connection connection = null;
       try {
           Class.forName("com.mysql.jdbc.Driver").newInstance();
           String url = "jdbc:mysql://192.168.1.1:3306/database_name";
           connection = (Connection) DriverManager.getConnection(url, "username", "password");
           Statement statement = (Statement) connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
           String sql = "select * from table_name";
           ResultSet resultSet = statement.executeQuery(sql);
           while (resultSet.next()) {
               Log.i("TAG", resultSet.getString("content"));
           }
       } catch (ClassNotFoundException | SQLException | InstantiationException | IllegalAccessException e) {
           e.printStackTrace();
       } finally {
           try {
               if (connection != null) {
                   connection.close();
               }
           } catch (SQLException e) {
               e.printStackTrace();
           }
       }
   }