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

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?

其他回答

你主要需要两样东西:

Add @ServletComponentScan to your Main Class You may add a package named filter inside it. You create a Filter class that has the following: @Component @Order(Ordered.HIGHEST_PRECEDENCE) public class RequestFilter implements Filter { // whatever field you have public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) { HttpServletResponse response = (HttpServletResponse) res; HttpServletRequest request = (HttpServletRequest) req; // Whatever implementation you want try { chain.doFilter(req, res); } catch(Exception e) { e.printStackTrace(); } } public void init(FilterConfig filterConfig) { } public void destroy() { } }

我看到Vasily Komarov的答案。这里有一个类似的方法,但是使用抽象的HandlerInterceptorAdapter类而不是使用HandlerInterceptor。

这里有一个例子……

@Component
public class CustomInterceptor extends HandlerInterceptorAdapter {
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
        throws Exception {
    }
}

@Configuration
public class InterceptorConfig extends WebMvcConfigurerAdapter {

    @Autowired
    private CustomInterceptor customInterceptor ;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(customInterceptor );
    }

}

更新:2022-05-29:

在Spring Boot 1.5.8中有两种简单的方法可以做到这一点。发布,不需要XML。

第一个方法:

如果你没有任何特定的URL模式,你可以像这样使用@Component(完整的代码和细节在这里https://github.com/surasint/surasint-examples/tree/master/spring-boot-jdbi/3_spring-boot-filter,看看README.txt开始):

@Component
public class ExampleFilter implements Filter {
    ...
}

第二种方式:

如果你想使用URL模式,你可以像这样使用@WebFilter(完整的代码和细节在这里https://github.com/surasint/surasint-examples/tree/master/spring-boot-jdbi/4_spring-boot-filter-urlpattern,看看README.txt开始):

@WebFilter(urlPatterns = "/api/count")
public class ExampleFilter implements Filter {
    ...
}

但是你也需要在你的@SpringBootApplication类中添加@ServletComponentScan注释:

@ServletComponentScan
@SpringBootApplication
public class MyApplication extends SpringBootServletInitializer {
    ...
}

注意@Component是Spring的注释,而@WebFilter不是。@WebFilter是Servlet 3注释。

这两种方法都只需要在pom.xml中有一个基本的Spring Boot依赖项(不需要显式地嵌入Tomcat jasper)

    <?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.8.RELEASE</version>
    </parent>

    <groupId>com.surasint.example</groupId>
    <artifactId>spring-boot-04</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <properties>
        <maven.compiler.target>1.8</maven.compiler.target>
        <maven.compiler.source>1.8</maven.compiler.source>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

警告:第一种方法,如果Spring Boot中的Controller返回到JSP文件,请求将通过过滤器两次。

而在第二种方式中,请求将只通过筛选器一次。

我更喜欢第二种方式,因为它更类似于Servlet规范中的默认行为。

过滤器,顾名思义,用于对资源的请求或资源的响应执行过滤,或同时对两者执行过滤。Spring Boot提供了一些选项来在Spring Boot应用程序中注册自定义过滤器。让我们看看不同的选项。

1. 定义Spring Boot过滤器和调用顺序

实现Filter接口,在Spring Boot中创建一个新的过滤器。

@Configuration
@Order(Ordered.HIGHEST_PRECEDENCE)
public class CustomFilter implements Filter {

    private static final Logger LOGGER = LoggerFactory.getLogger(CustomFilter.class);

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        LOGGER.info("########## Initiating Custom filter ##########");
    }

    @Override
    public void doFilter(ServletRequest servletRequest,
                         ServletResponse servletResponse,
                         FilterChain filterChain)
                         throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        LOGGER.info("Logging Request  {} : {}", request.getMethod(), request.getRequestURI());

        // Call next filter in the filter chain
        filterChain.doFilter(request, response);

        LOGGER.info("Logging Response :{}", response.getContentType());
    }

    @Override
    public void destroy() {
        // TODO: 7/4/2018
    }
}

让我们快速看一下上面代码中的一些要点

@Component注释注册的过滤器。 为了以正确的顺序触发过滤器,我们需要使用@Order注释。 @ component @Order (1) 公共类CustomFirstFilter实现了Filter { } @ component @Order (2) 公共类CustomSecondFilter实现了Filter { }

在上面的代码中,CustomFirstFilter将在CustomSecondFilter之前运行。

数字越低,优先级越高

2. URL模式

如果基于约定的映射不够灵活,我们可以使用FilterRegistrationBean对应用程序进行完全控制。在这里,不要为过滤器类使用@Component注释,而是使用FilterRegistrationBean注册过滤器。

public class CustomURLFilter implements Filter {

    private static final Logger LOGGER = LoggerFactory.getLogger(CustomURLFilter.class);

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        LOGGER.info("########## Initiating CustomURLFilter filter ##########");
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {

        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        LOGGER.info("This Filter is only called when request is mapped for /customer resource");

        // Call the next filter in the filter chain
        filterChain.doFilter(request, response);
    }

    @Override
    public void destroy() {

    }
}

使用FilterRegistrationBean注册自定义过滤器。

@Configuration
public class AppConfig {

    @Bean
    public FilterRegistrationBean < CustomURLFilter > filterRegistrationBean() {
        FilterRegistrationBean < CustomURLFilter > registrationBean = new FilterRegistrationBean();
        CustomURLFilter customURLFilter = new CustomURLFilter();

        registrationBean.setFilter(customURLFilter);
        registrationBean.addUrlPatterns("/greeting/*");
        registrationBean.setOrder(2); // Set precedence
        return registrationBean;
    }
}

这是一个建议而不是答案,但如果你在你的web应用程序中使用Spring MVC,最好使用Spring HandlerInterceptor而不是Filter。

它可以做同样的工作,但是

可以使用ModelAndView吗 它的方法可以在请求处理之前和之后调用,或者在请求完成之后调用。 它很容易测试

1. 实现HandlerInterceptor接口,并向类中添加@Component注释

@Component
public class SecurityInterceptor implements HandlerInterceptor {

    private static Logger log = LoggerFactory.getLogger(SecurityInterceptor.class);

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        request.getSession(true);
        if(isLoggedIn(request))
            return true;

        response.getWriter().write("{\"loggedIn\":false}");
        return false;
    }

    private boolean isLoggedIn(HttpServletRequest request) {
        try {
            UserSession userSession = (UserSession) request.getSession(true).getAttribute("userSession");
            return userSession != null && userSession.isLoggedIn();
        } catch(IllegalStateException ex) {
            return false;
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView) throws Exception {

    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex) throws Exception {

    }
}

2. 配置拦截器

@Configuration
public class WebConfig implements WebMvcConfigurer {

    private HandlerInterceptor securityInterceptor;

    @Autowired
    public void setSecurityInterceptor(HandlerInterceptor securityInterceptor) {
        this.securityInterceptor = securityInterceptor;
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(securityInterceptor).addPathPatterns("/**").excludePathPatterns("/login", "/logout");
    }

}