Servlet3.0から@WebServlet(urlPatterns={"hoge"})を使えばweb.xmlにURLマッピング定義が要らない ref: http://qiita.com/nikuyoshi/items/d9857aa74065f4f67794

LoginForm.java

@WebServlet(urlPatterns={"/LoginForm"})
public class LoginForm extends HttpServlet{ 
  @Override
  public void doPost(HttpServletRequest request, HttpServletResponse response){
  }
}

web.xml

<web-app>
    <servlet>
        <servlet-name>LoginForm</servlet-name>
        <servlet-class>com.github.nikuyoshi.form.LoginForm</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LoginForm</servlet-name>
        <url-pattern>/LoginForm</url-pattern>
    </servlet-mapping>
</web-app>