修改：使用新的/<username>/userpage路由

app/templates/admin_index.html

@@ -30,7 +30,7 @@
             <div class="collapse navbar-collapse" id="navbarNav">
                 <ul class="navbar-nav">
                     <li class="nav-item">
-                        <a class="nav-link" href="/{{ username }}">返回 {{ username }}</a>
+                        <a class="nav-link" href="/{{ username }}/userpage">返回 {{ username }}</a>
                     </li>
                 </ul>
             </div>

app/templates/mainpage_get.html

@@ -23,7 +23,7 @@
     <div class="container-fluid">
         <p><b><font size="+3" color="red">English Pal - Learn English smartly!</font></b></p>
         {% if session['logged_in'] %}
-            <a href="/{{ session['username'] }}">{{ session['username'] }}</a>
+            <a href="/{{ session['username'] }}/userpage">{{ session['username'] }}</a>
             {% if session['username'] == admin_name %}
             <a href="/admin">管理</a></p>
             {% endif %}