public class BaseFilter implements Filter { @Override public void init(FilterConfig filterConfig) throws ServletException { // 初始化 } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { HttpServletRequest httpRequest = (HttpServletRequest) request; HttpServletResponse httpResponse = (HttpServletResponse) response; String requestURI = httpRequest.getRequestURI(); if (requestURI.endsWith("load.jsp") || requestURI.endsWith("load.action")) { // 如果是load.jsp或load.action请求，则直接放行 chain.doFilter(request, response); return; } HttpSession session = httpRequest.getSession(false); if (session != null && session.getAttribute("user") != null) { // 如果已经登录，则放行请求 chain.doFilter(request, response); return; } // 否则跳转到登录页面 httpResponse.sendRedirect("/load.jsp"); } @Override public void destroy() { // 销毁 } }补全代码

这段代码是一个基础的过滤器实现，用于过滤所有的请求，检查用户是否已经登录，如果没有登录则跳转到登录页面。

完整的代码如下：

public class BaseFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // 初始化
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        HttpServletResponse httpResponse = (HttpServletResponse) response;

        String requestURI = httpRequest.getRequestURI();
        if (requestURI.endsWith("load.jsp") || requestURI.endsWith("load.action")) {
            // 如果是load.jsp或load.action请求，则直接放行
            chain.doFilter(request, response);
            return;
        }

        HttpSession session = httpRequest.getSession(false);
        if (session != null && session.getAttribute("user") != null) {
            // 如果已经登录，则放行请求
            chain.doFilter(request, response);
            return;
        }

        // 否则跳转到登录页面
        httpResponse.sendRedirect("/load.jsp");
    }

    @Override
    public void destroy() {
        // 销毁
    }
}