Spring Boot中是否有Filter类(用于web应用程序)的注释?也许@Filter ?

我想在我的项目中添加一个自定义过滤器。

Spring Boot参考指南中提到过 FilterRegistrationBean,但我不确定如何使用它。


当前回答

没有特殊的注释来表示servlet筛选器。您只需声明一个Filter类型的@Bean(或FilterRegistrationBean)。在Boot自己的EndpointWebMvcAutoConfiguration中有一个例子(为所有响应添加自定义头);

如果你只声明一个过滤器,它将被应用到所有的请求。如果您还添加了一个FilterRegistrationBean,您可以另外指定要应用的单个servlet和url模式。

注意:

从Spring Boot 1.4开始,FilterRegistrationBean不再弃用,而是简单地将包从org.springframework. Boot .context. embedd.filterregistrationbean移动到org.springframework.boot.web.servlet.FilterRegistrationBean

其他回答

添加过滤器有三种方法,

用一个Spring原型(如@Component)注释你的过滤器 在Spring @Configuration中注册一个Filter类型的@Bean 在Spring @Configuration中用FilterRegistrationBean类型注册一个@Bean

Either #1 or #2 will do if you want your filter applies to all requests without customization, use #3 otherwise. You don't need to specify component scan for #1 to work as long as you place your filter class in the same or sub-package of your SpringApplication class. For #3, use along with #2 is only necessary when you want Spring to manage your filter class such as have it auto wired dependencies. It works just fine for me to new my filter which doesn't need any dependency autowiring/injection.

虽然结合#2和#3效果很好,但我很惊讶它最终没有应用两次两个过滤器。我的猜测是,当Spring调用相同的方法来创建这两个bean时,它将这两个bean合并为一个。如果您想单独使用#3和authwiring,您可以使用AutowireCapableBeanFactory。举例如下:

private @Autowired AutowireCapableBeanFactory beanFactory;

    @Bean
    public FilterRegistrationBean myFilter() {
        FilterRegistrationBean registration = new FilterRegistrationBean();
        Filter myFilter = new MyFilter();
        beanFactory.autowireBean(myFilter);
        registration.setFilter(myFilter);
        registration.addUrlPatterns("/myfilterpath/*");
        return registration;
    }

此过滤器还将帮助您允许跨源访问

@Component
@Order(Ordered.HIGHEST_PRECEDENCE)
public class SimpleCORSFilter implements Filter {

    public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {

            HttpServletResponse response = (HttpServletResponse) res;
            HttpServletRequest request = (HttpServletRequest) req;
            response.setHeader("Access-Control-Allow-Origin", "*");
            response.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, DELETE");
            response.setHeader("Access-Control-Max-Age", "20000");
            response.setHeader("Access-Control-Allow-Headers", "x-requested-with, authorization, Content-Type, Authorization, credential, X-XSRF-TOKEN");

            if("OPTIONS".equalsIgnoreCase(request.getMethod())) {
                response.setStatus(HttpServletResponse.SC_OK);
            } else {
                chain.doFilter(req, res);
            }
    }


    public void destroy() {}

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        // TODO Auto-generated method stub

    }

}

使用Spring注册过滤器大约有四种不同的选项。

首先,我们可以创建一个实现Filter或扩展HttpFilter的Spring bean:

@Component
public class MyFilter extends HttpFilter {

    @Override
    protected void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain) 
        throws IOException, ServletException {
        // Implementation details...

        chain.doFilter(request, response);
    }
}

其次,我们可以创建一个扩展GenericFilterBean的Spring bean:

@Component
public class MyFilter extends GenericFilterBean {

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain)
  throws IOException, ServletException {
    //Implementation details...

        chain.doFilter(currentRequest, servletResponse);
    }
}

我们也可以使用FilterRegistrationBean类:

@Configuration
public class FilterConfiguration {

    private final MyFilter myFilter;

    @Autowired
    public FilterConfiguration(MyFilter myFilter) {
        this.myFilter = myFilter;
    }

    @Bean
    public FilterRegistrationBean<MyFilter> myFilterRegistration() {
        FilterRegistrationBean<DateLoggingFilter> filterRegistrationBean = new FilterRegistrationBean<>();
        filterRegistrationBean.setFilter(myFilter);
        filterRegistrationBean.setUrlPatterns(Collections.singletonList("/*"));
        filterRegistrationBean.setDispatcherTypes(DispatcherType.REQUEST);
        filterRegistrationBean.setOrder(Ordered.LOWEST_PRECEDENCE - 1);
        return filterRegistrationBean;
    }
}

最后,我们可以使用@ServletComponentScan的@WebFilter注释:

@WebFilter(urlPatterns = "/*", dispatcherTypes = {DispatcherType.REQUEST})
public class MyFilter extends HttpFilter {

    @Override
    protected void doFilter(HttpServletRequest request, HttpServletResponse response, FilterChain chain)
  throws IOException, ServletException {
        // Implementation details...

        chain.doFilter(request, response);
    }
}

对于Spring Boot在我所做的任何配置类:

@Bean
public OncePerRequestFilter myFilter() {
    return new OncePerRequestFilter() {
        @Override
        protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
            AuthUser authUser = SecurityUtil.safeGet(); // applied after secutiry filters
            ...
            filterChain.doFilter(request, response);
        }
    };
}

这就是全部,不需要任何注册。参见什么是OncePerRequestFilter?

如果您想要设置一个第三方过滤器,您可以使用FilterRegistrationBean。

例如,等价的web.xml:

<filter>
     <filter-name>SomeFilter</filter-name>
        <filter-class>com.somecompany.SomeFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>SomeFilter</filter-name>
    <url-pattern>/url/*</url-pattern>
    <init-param>
        <param-name>paramName</param-name>
        <param-value>paramValue</param-value>
    </init-param>
</filter-mapping>

这将是@Configuration文件中的两个bean:

@Bean
public FilterRegistrationBean someFilterRegistration() {

    FilterRegistrationBean registration = new FilterRegistrationBean();
    registration.setFilter(someFilter());
    registration.addUrlPatterns("/url/*");
    registration.addInitParameter("paramName", "paramValue");
    registration.setName("someFilter");
    registration.setOrder(1);
    return registration;
}

public Filter someFilter() {
    return new SomeFilter();
}

以上是用Spring Boot 1.2.3测试的。