如何在Java中的过滤器链中跳过过滤器

Question

我的应用程序中有2个过滤器。根据某些条件，我想选择是否执行第二个过滤器。有没有办法做到这一点？

我做了一些谷歌搜索，但没有成功。我希望请求继续执行而不执行第二个过滤器。那可能吗？

任何帮助将不胜感激。

Answer 1

您可以在请求中设置一个属性，然后在第二个过滤器中对其进行检查。

public class FirstFilter implements Filter {
    //...

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        servletRequest.setAttribute("executeSecondFilter", true);
        //...
        if(someReason)
            servletRequest.setAttribute("executeSecondFilter", false);
        filterChain.doFilter(servletRequest, servletResponse);
    }
}

public class SecondFilter implements Filter {
    //..

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        if (servletRequest.getAttribute("executeSecondFilter") == null || !((Boolean) servletRequest.getAttribute("executeSecondFilter"))) {
            filterChain.doFilter(servletRequest, servletResponse);
        }
        //...
    }
}

您可以像这样简化上面的代码：

public class FirstFilter implements Filter {
    //...

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        //...
        if(someReason)
            servletRequest.setAttribute("executeSecondFilter", false);
        filterChain.doFilter(servletRequest, servletResponse);
    }
}

public class SecondFilter implements Filter {
    //..

    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        if (servletRequest.getAttribute("executeSecondFilter") != null) {
            filterChain.doFilter(servletRequest, servletResponse);
        }
        //...
    }
}

这样，您只需检查属性“ executeSecondFilter”的存在