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

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() { } }

其他回答

Use:

@WebFilter(urlPatterns="/*")
public class XSSFilter implements Filter {

    private static final org.apache.log4j.Logger LOGGER = LogManager.getLogger(XSSFilter.class);

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

    @Override
    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
            throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        HttpRequestWrapper requestWrapper = new HttpRequestWrapper(req);
        chain.doFilter(requestWrapper, response);
    }

    @Override
    public void destroy() {
        LOGGER.info("Destroying XSSFilter... ");
    }

}

你需要实现Filter,并且它需要用@WebFilter(urlPatterns="/*")进行注释。

在Application或Configuration类中,您需要添加@ServletComponentScan。通过此操作,您的筛选器将被注册。

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);
    }
}

你可以在实现javax.servlet.Filter的类上使用@WebFilter javax.servlet.annotation.WebFilter:

@WebFilter(urlPatterns = "/*")
public class MyFilter implements Filter {
}

然后使用@ServletComponentScan注册。

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

    }

}

对于基于任何条件和spring引导中的任何列表的过滤,查询语言更加灵活,并允许我们向下过滤到我们需要的确切资源。 例如,如果我们有一个简单的实体,如User,并像这样定义它。

@Entity
public class User {
@Id
@GeneratedValue(strategy = 
GenerationType.AUTO)
private Long id;

private String firstName;
private String lastName;
private String email;

private int age;

//Setter and getter as usual

然后我们创建一个实现Specification接口的UserSpecification,我们将传递我们自己的约束来构造实际的查询。在本部分中,与标准和构建器相关的方法非常有用和灵活。

public class UserSpecification implements Specification<User> {

private SearchCriteria criteria;

@Override
public Predicate toPredicate
  (Root<User> root, CriteriaQuery<?> query, CriteriaBuilder builder) {

    if (criteria.getOperation().equalsIgnoreCase(">")) {
        return builder.greaterThanOrEqualTo(
          root.<String> get(criteria.getKey()), criteria.getValue().toString());
    } 
    else if (criteria.getOperation().equalsIgnoreCase("<")) {
        return builder.lessThanOrEqualTo(
          root.<String> get(criteria.getKey()), criteria.getValue().toString());
    } 
    else if (criteria.getOperation().equalsIgnoreCase(":")) {
        if (root.get(criteria.getKey()).getJavaType() == String.class) {
            return builder.like(
              root.<String>get(criteria.getKey()), "%" + criteria.getValue() + "%");
        } else {
            return builder.equal(root.get(criteria.getKey()), criteria.getValue());
        }
    }
    return null;
}
}

此外,我们还创建了一个基于以下SearchCriteria类中表示的一些简单约束的规范,任何条件都可以像这样创建:

public class SearchCriteria {
private String key;
private String operation;
private Object value;
 }

最后定义UserRepository和扩展JpaSpecificationExecutor,

public interface UserRepository 
extends JpaRepository<User, Long>, 
JpaSpecificationExecutor<User> {}