Spring Boot filter

在Spring Boot中自定义filter

本文我们将会讲解如何在Spring Boot中自定义filter并指定执行顺序。

定义Filter很简单，我们只需要实现Filter接口即可，同时我们可指定@Order来确定其执行顺序，我们定义两个filter如下：

@Slf4j

@Component

@Order(1)

public class TransactionFilter implements Filter {

    @Override

    public void doFilter(

    ServletRequest request,

    ServletResponse response,

    FilterChain chain) throws IOException, ServletException

    {

        HttpServletRequest req = (HttpServletRequest) request;

        log.info(

                "Starting a transaction for req : {}",

                req.getRequestURI());

        chain.doFilter(request, response);

        log.info(

                "Committing a transaction for req : {}",

                req.getRequestURI());

    }

    // other methods

}

@Slf4j

@Component

@Order(2)

public class RequestResponseLoggingFilter implements Filter {

    @Override

    public void doFilter(

            ServletRequest request,

            ServletResponse response,

            FilterChain chain) throws IOException, ServletException {

        HttpServletRequest req = (HttpServletRequest) request;

        HttpServletResponse res = (HttpServletResponse) response;

        log.info(

                "Logging Request  {} : {}", req.getMethod(),

                req.getRequestURI());

        chain.doFilter(request, response);

        log.info(

                "Logging Response :{}",

                res.getContentType());

    }

    // other methods

}

注意在Spring Boot中我们需要使用@Component来实例化Filter从而在Spring Boot中生效。

@Order指定了两个fiter的顺序。

上面的例子我们指定了两个fiter对于所有的url生效，如果我们希望filter对于特定的某些url生效该怎么办呢？

我们可使用FilterRegistrationBean来手动注册对于的Filter：

    @Bean

    public FilterRegistrationBean<UrlFilter> loggingFilter(){

        FilterRegistrationBean<UrlFilter> registrationBean

                = new FilterRegistrationBean<>();

        registrationBean.setFilter(new UrlFilter());

        registrationBean.addUrlPatterns("/users/*");

        return registrationBean;

    }

上面我们同时指定了filter对应的urlPatttern。

本文的例子可以参考 https://github.com/ddean2009/learn-springboot2/tree/master/springboot-filter

更多教程请参考 flydean的博客

巴特西

Spring Boot filter

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