What are the effects of filters?

Can verify that the customer is from a trusted network, can re-encode the data submitted by the customer, can get the configuration information from the system, can filter out some of the customer should not

The words that appear, can verify whether the user is logged in, can verify whether the client's browser supports the current application, can record the system's log, etc.

What is the use of filters?

The first thing to do is to implement the (implements) filter interface and overwrite the three methods of the filter interface:

//用于获得FilterConfig对象；doFilter(ServletRequest request, ServletResponse response, FilterChain chain) //进行过滤处理一些业务；

What are the effects of filters?