1.创建过滤器(Filter)：
需要继承Filter
public void init(FilterConfig filterConfig) throws ServletException {
System.out.println("InitFilter过滤器创建");
}
2.过滤器功能（处理Web格式）：
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
servletResponse.setContentType("text/html;charset=utf-8");
servletRequest.setCharacterEncoding("utf-8");
servletResponse.setCharacterEncoding("utf-8");
filterChain.doFilter(servletRequest,servletResponse);
}
3.过滤器销毁：
public void destroy() {
System.out.println("InitFilter过滤器销毁");
}
