下面是我的doGet方法

@WebServlet(
        name = "IndexServlet",
        urlPatterns={ "/", "/home" },
        initParams = { @WebInitParam(name = "sortBy", value = Constants.POPULAR) }
)
public class IndexServlet extends HttpServlet {

    private DataSource pool;

    @Override
    public void init() throws ServletException {
        String datasource_name = "jdbc/bookhive_db";
        try {
            //A JNDI Initial context to be able to lookup the DataSource
            InitialContext ctx = new InitialContext();
            pool = (DataSource) ctx.lookup("java:comp/env/" + datasource_name);
            if (pool == null)
                throw new ServletException("Unknown DataSource '" + datasource_name + "'");
        } catch (NamingException ex) {
            ex.printStackTrace();
        }
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        int page;
        try {
            page = Integer.parseInt(request.getParameter("page"));
        } catch (NumberFormatException e) {
            page = 1;
        }

        String sortBy = request.getParameter("sortBy");
        if (sortBy == null || sortBy.isEmpty())
            sortBy = this.getInitParameter("sortBy");

        String query = getQuery(sortBy);
        Object[] params = {
                (page - 1) * Constants.RESULTS_PER_PAGE,
                Constants.RESULTS_PER_PAGE
        };

        JDBCService service = new JDBCService(pool);
        service.setQuery(query);
        service.setParams(params);
        List<Book> books = service.getBookDetails();


        System.out.println("HELLO");

        RequestDispatcher dispatcher = request.getRequestDispatcher("/WEB-INF/index.jsp");
        dispatcher.forward(request, response);
    }
}

当我启动服务器（Tomcat）时，它将http://localhost:8080在浏览器中打开，该doGet方法被调用3次。它会打印“ Hello”
3次。

这仅在我第一次启动服务器时发生。

知道为什么会这样吗？