Eclipse 程序连接 MySQL 服务器时崩溃

Question

我正在编写一个简单的程序来连接到本地托管的 MySQL 服务器。我已确保服务器正在运行。 我尝试执行的代码如下：

void CSlaveController::fnDatabaseConnection(){

  sql::Driver *driver;
  sql::Connection *connection;
  sql::ResultSet *result;
  sql::Statement *statement;
  sql::PreparedStatement *prepared;
  driver = get_driver_instance();

  connection = driver->connect("tcp://127.0.0.1:3306","DBServer","root"); /*Where the program crashes*/

  statement = connection->createStatement();
  statement->execute("SHOW DATABASES");

  delete statement;
  delete connection;
}

我注意到的问题之一是当我运行程序时找不到头文件mysql_connection.h。当我构建项目时，没有出现任何问题。 但是当我运行程序时，它崩溃了，这就是我所看到的：。我已经仔细检查了包含内容，甚至手动添加了该特定文件。

关于我可能做错了什么有什么想法吗？如果图像太多，我很抱歉，我觉得这将是传达最多信息的最佳方式。

Answer 1

@WebServlet("/uploadServlet")
@MultipartConfig(maxFileSize = 160000) // upload file's size up to 16MB /
                                            // 16000000 byte
public class FileUploadToDataBaseServlet extends HttpServlet {
    /*
     * FileUploadToDataBaseServlet:  files upload to database with Servlet, JSP
     * and MySQL. Creating MySQL database table. Coding upload form page. Coding
     * file upload servlet. Coding message page. Testing the application and
     * verifying file stored in database.
     */
    
    private String databaseURL = "jdbc:mysql://localhost:3306/MyDatabase";
    private String databaseUser = "root";
    private String databasePassWord = "2888";

    /*
     * This method is called by servlet service method to handle the POST
     * request from client. The HTTP POST method allows the client to send data
     * of unlimited length to the Web server a single time and is useful when
     * posting information to the server.
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // gets values of text fields
        String firstName = request.getParameter("firstName");
        String lastName = request.getParameter("lastName");
        String phone = request.getParameter("phone");
        String email = request.getParameter("email");
        String country = request.getParameter("country");
        String photo = request.getParameter("photo");

        // InputStream's are used for reading byte based data
        InputStream inputStream = null; // input stream of the upload file

        // obtains the upload file part in this multipart request

        Part filePart = request.getPart("photo");
        if (filePart != null) {
            // prints out some information for debugging
            System.out.println(filePart.getName());
            System.out.println(filePart.getSize());
            System.out.println(filePart.getContentType());

            // obtains input stream of the upload file
            inputStream = filePart.getInputStream();
        }

        Connection connection = null; // connection to the database
        String message = null; // message will be sent back to client

        try {
            // connects to the database
            DriverManager.registerDriver(new com.mysql.jdbc.Driver());
            connection = DriverManager.getConnection(databaseURL, databaseUser, databasePassWord);

            // constructs SQL statement
            String sql = "INSERT INTO registration (first_name, last_name, phone, email, country, photo )"
                    + "values (?, ?, ?, ?, ?, ?)";

            // The performance of the application will be faster if you use
            // PreparedStatement,
            // which gives better performance than Statement class.

            PreparedStatement statement = connection.prepareStatement(sql);
            statement.setString(1, firstName);
            statement.setString(2, lastName);
            statement.setString(3, phone);
            statement.setString(4, email);
            statement.setString(5, country);

            if (inputStream != null) {
                // bring input stream of the upload file for the blob column
                statement.setBlob(6, inputStream);
            }

            // sends the statement to the database server
            int row = statement.executeUpdate();
            if (row > 0) {
                message = "File uploaded and saved into database";
            }
        } catch (SQLException exception) {
            message = "ERROR: " + exception.getMessage();
            exception.printStackTrace();
        } finally {
            if (connection != null) {
                // closes the database connection
                try {
                    connection.close();
                } catch (SQLException exception) {
                    exception.printStackTrace();
                }
            }
            // sets the message in request scope
            request.setAttribute("Message", message);

            // forwards message to the page
            getServletContext().getRequestDispatcher("/Alert.html").forward(request, response);
        }

    }
}