按照书上的步骤来的
1.在bootstrap中编写了base.html，放在templates/bootstrap目录下的
代码：

  1 {% block doc -%}
  2 
  3 
  4 {%- block html %}
  5   
  6     {%- block head %}
  7     
  8 
  9     {%- block metas %}
 10     
 11     {%- endblock metas %}
 12 
 13     {%- block styles %}
 14     
 15     
 16     {%- endblock styles %}
 17     {%- endblock head %}
 18   
 19   
 20     {% block body -%}
 21     {% block navbar %}
 22     {%- endblock navbar %}
 23     {% block content -%}
 24     {%- endblock content %}
 25 
 26     {% block scripts %}
 27     
 28     
 29     {%- endblock scripts %}
 30     {%- endblock body %}
 31   
 32 {%- endblock html %}
 33 
 34 {% endblock doc -%}

然后在templates下编写了base.html

  1 {% extends "bootstrap/base.html" %}
  2 {% block title %}Flasky{% endblock %}
  3 {% block navbar %}
  4 
  5 
  6 

  8     

  9       
 11         Toggle navigation
 12         
 13         
 14         
 15       
 16       Flasky
 17     
 18     

 19       

 20         
Home
 21       
 22     

 23   

 24 

 25 
 26 
 27 {% endblock %}
 28 
 29 {% block content %}
 30 
 31 
 32 

 33   {% block page_content %}{% endblock %}
 34 
 35 
 36 
 37 {% endblock %}

还有404.html

  1 { % extends "base.html" % }
  2 { % block title % }Flasky - Page Not Found{ % endblock % }
  3 { % block page_content % }
  4 

  5         
Not Found
  6 

  7 { % endblock % }
~                       

接着是python脚本语言

  1 from flask import Flask,render_template
  2 from flask_bootstrap import Bootstrap
  3 
  4 app = Flask(__name__)
  5 Bootstrap(app)
  6 
  7 @app.route('/user/')
  8 def user(name):
  9     return render_template('user.html', name = name)
 10 @app.errorhandler(404)
 11 def page_not_found(e):
 12     return render_template('404.html'),404
 13 
 14 @app.errorhandler(500)
 15 def internal_server_error(e):
 16     return render_template('500.html'),500
 17 if __name__ == "__main__":
 18     app.run()

可是最后在网页上却显示这样的结果:

我早浏览器中输入的地址是：
127.0.0.1:5000/ab

{ % extends "base.html" % } { % block title % }Flasky - Page Not Found{ % endblock % } { % block page_content % }
Not Found
{ % endblock % }