request对象添加额外的参数

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

/**
 * <p>filter---参数过滤器</p><br>
 * <p>请求已经有该参数，（过滤器覆盖value是无效的）</p><br>
 * TODO(设置自定义request参数)
 *
 * @author han.sun
 * @version 1.0.0
 * @since 2019/5/5 13:12
 */
public class RequestParameterFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) {
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        String msgId = request.getParameter("msgId");
        if (msgId == null) {
            Map<String, Object> map = new HashMap<String, Object>(16);
            map.put("msgId", new String[]{System.currentTimeMillis() + ""});
            RequestParameterWrapper requestParameterWrapper = new RequestParameterWrapper(request, map);
            chain.doFilter(requestParameterWrapper, servletResponse);
        }else {
            chain.doFilter(servletRequest, servletResponse);
        }
    }

    @Override
    public void destroy() {
    }
}