Java -如何在接口实现中获取http头？

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;

public class HeaderFilter implements Filter {
    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // 初始化操作
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        
        // 获取指定的HTTP头信息
        String userAgent = request.getHeader("User-Agent");
        
        // 处理或存储HTTP头信息
        // ...
        
        // 继续处理请求
        filterChain.doFilter(servletRequest, servletResponse);
    }

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