Servlet Filters are an implementation of the Chain of responsibility design pattern.
All filters are chained (in the order of their definition in web.xml). The chain.doFilter()
is proceeding to the next element in the chain. The last element of the chain is the target resource/servlet.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…