错误现场：
NoReverseMatch at /user/login_handler
Reverse for ‘index’ with arguments ‘()’ and keyword arguments ‘{}’ not found. 0 pattern(s) tried: []
经过分析，发现由于book/urls里面设置index参数的匹配正则，在做反向解析的时候又没有参数传递过去，导致这个问题出现错误提示没有匹配到参数！故解决办法添加参数在 反向解析的时候，故问题解决
修改前：url(r’^$’, views.index),
urlpatterns = [
url(r'^$', views.index),
url(r'^books$', views.select_all, name="select_all"),
url(r'^book/(?P<bid>\d+)$', views.select_by_id, name="select_by_id"),
]
修改后：url(r’^$’, views.index,name=‘index’),
urlpatterns = [
url(r'^$', views.index,name='index'),
url(r'^books$', views.select_all, name="select_all"),
url(r'^book/(?P<bid>\d+)$', views.select_by_id, name="select_by_id"),
]
修改后问题解决