Web后端开发-使用Filter过滤器技术，实现访问量统计

package filters; import java.io.IOException; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.annotation.WebFilter; import javax.servlet.annotation.WebInitParam; /** * Servlet Filter implementation class IndexFilter */ @WebFilter( urlPatterns = { "/indexservlet" }, initParams = { @WebInitParam(name = "count", value = "0") }) public class IndexFilter implements Filter { private int count; /** * Default constructor. */ public IndexFilter() { // TODO Auto-generated constructor stub } /** * @see Filter#destroy() */ public void destroy() { // TODO Auto-generated method stub } /** * @see Filter#doFilter(ServletRequest, ServletResponse, FilterChain) */ public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { //可以写过滤验证的业务代码 System.out.println("IndexFilter执行了"); count++; System.out.println("count:"+count); chain.doFilter(request, response); } /** * @see Filter#init(FilterConfig) */ public void init(FilterConfig fConfig) throws ServletException { this.count = Integer.parseInt(fConfig.getInitParameter("count")); } }