Filter执行过程是什么？

3）Filter执行的顺序
马克-to-win：根据上面的说明“Filter的拦截的工作过程”的图，我们对Filter的Helloworld例子做一个小小的扩展（增加了一个 MarkToWinFilter2，代码和MarkToWinFilter几乎一样），来说明Filter的顺序，结论：filter-mapping在Web.xml中的顺序决定了Filter执行的顺序。
例 1.2.3
Web.xml中增加下一段：
     <filter>
        <filter-name>MarkToWinFilter2</filter-name>
        <filter-class>com.MarkToWinFilter2</filter-class>
    </filter>
    <filter>
        <filter-name>MarkToWinFilter</filter-name>
        <filter-class>com.MarkToWinFilter</filter-class>
    </filter>
<filter-mapping>
      <filter-name>MarkToWinFilter</filter-name>
      <url-pattern>/*</url-pattern>
</filter-mapping>
    <filter-mapping>
      <filter-name>MarkToWinFilter2</filter-name>
      <url-pattern>/*</url-pattern>
</filter-mapping>

package com;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.*;
public class MarkToWinFilter2 implements Filter {
    public void destroy() {
    }
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        response.setCharacterEncoding("GBK");
        PrintWriter out = response.getWriter();
        out.println("之前 filterChain.doFilter2");
        System.out.println("之前 filterChain.doFilter2");
        chain.doFilter(request, response);
        System.out.println("之后 filterChain.doFilter2");
        out.println("之后 filterChain.doFilter2");
    }
    public void init(FilterConfig fConfig) throws ServletException {
    }
}