tomcat - 网络应用程序。设置 servlet TrackingFilter 后不显示任何内容

Question

我使用 tomcat 创建了一个简单的网络应用程序来测试跟踪过滤器。问题是 webapp 在没有跟踪过滤器的情况下工作正常。但是，当我实现跟踪过滤器时，webapp 不显示任何内容。我能够在 eclipse 的控制台上看到跟踪信息，但在浏览器上什么也看不到。

我的跟踪过滤器代码:

package com.myapp.filters;
import java.io.IOException;
import java.net.InetAddress;
import java.util.Date;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class TrackingFilter implements Filter{

private FilterConfig config =null;

@Override
public void destroy() {
    // TODO Auto-generated method stub

}

@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
    HttpServletRequest httpReq = (HttpServletRequest)req;
    /*
     * Date of website entering
     */
    Date now = new Date();
    String host = httpReq.getHeader("host");
    String ip = InetAddress.getLocalHost().getHostAddress();

    config.getServletContext().log("TrackingFilter. " + "Date: " + now + ",  " + "host: " + host + ", " + "IP: " + ip);


    System.out.println("Exiting tracking filtering");

}

@Override
public void init(FilterConfig config) throws ServletException {
    this.config = config;

}
}

我的 web.xml 配置

<!-- Tracking Filter -->
<filter>
    <filter-name>Tracking Filter</filter-name>
    <filter-class>com.myapp.filters.TrackingFilter</filter-class>
</filter>

<filter-mapping>
    <filter-name>Tracking Filter</filter-name>
    <url-pattern>/*</url-pattern>   
</filter-mapping>

Answer 1

那是因为过滤器打断了链条，不会将请求传播到下一个过滤器和 servlet。它应该包含

chain.doFilter(req, res);