java代码实现onceperrequestfilter拦截token

好的，我了解了您的问题。实现 "onceperrequestfilter" 拦截 "token" 的Java代码如下：

import javax.servlet.Filter;
import javax.servlet.FilterConfig;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class TokenFilter implements Filter {

    private static final String TOKEN_HEADER = "X-Auth-Token";

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

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest httpRequest = (HttpServletRequest) request;
        HttpServletResponse httpResponse = (HttpServletResponse) response;
        String token = httpRequest.getHeader(TOKEN_HEADER);
        if (token == null) {
            httpResponse.setStatus(HttpServletResponse.SC_UNAUTHORIZED);
            return;
        }

        // Perform additional validation on the token if required

        chain.doFilter(request, response);
    }

    @Override
    public void destroy() {
    }
}

该代码使用 Filter 拦截每个请求，并检查 X-Auth-Token 标头是否存在。如果标头不存在，则返回 HTTP 状态码 401（未授权）。否则，将继续执行过滤器链，允许请求进行进一步处理。您可以在此基础上进行修改，以执行其他逻辑，例如进一步验证令牌的有效性等。