如何制作URL过滤器以使用Servlet路由动作？

我看到3种方式：过滤器，基本servlet（通过主servlet的所有请求）或“ servlet映射”

过滤

这个例子重写URL

http://example.org/ <整数值>

至

http://example.org/user?id= <整数值>

即

http://example.org/1234-> http://example.org/user?id=1234

1. 确定web.xml中的过滤器

     <filter>         <filter-name>Router</filter-name>         <filter-class>org.example.Router</filter-class>        <init-param>  <param-name>param1</param-name>  <param-value>valueOfparam1</param-value>         </init-param>     </filter>     <filter-mapping>         <filter-name>Router</filter-name>         <url-pattern>/*</url-pattern>     </filter-mapping>

在init-param部分中，您可以指定路由规则

1. 过滤器类

        public class Router implements javax.servlet.Filter {    private static final Pattern REWRITE_PATTERN = Pattern.compile("(^[1-9]\d*)$");    @Override    public void destroy() {    }    @Override    public void doFilter(ServletRequest req, ServletResponse res, FilterChain fc) throws IOException, ServletException {    //this method calling before controller(servlet), every request        HttpServletRequest request = (HttpServletRequest) req;        String url = request.getRequestURL().toString();        String number = url.substring(url.lastIndexOf("/")).replace("/", "");        Matcher m = REWRITE_PATTERN.matcher(number);        if(m.find()) { RequestDispatcher dispatcher = request.getRequestDispatcher("user?id=" + m.group(1)); dispatcher.forward(req, res);        } else { fc.doFilter(req, res);        }    }    @Override    public void init(FilterConfig fc) throws ServletException {        //here you may read params from web.xml    }}

基本Sevlet

    public class BasicServlet extends HttpServlet {       //route rules here, and rewrite    }

servlet映射

    <servlet-mapping>        <servlet-name>UserServlet</servlet-name>        <uri-mapping>/user/*</uri-mapping>    </servlet-mapping>    <servlet-mapping>        <servlet-name>PostServlet</servlet-name>        <uri-mapping>/post/*</uri-mapping>    </servlet-mapping>

• 过滤器-更灵活，不需要认真修改工作代码
• 基本servlet-灵活，需要更改您的代码
• Servlet映射-简单，不灵活（针对特定的路由规则）