如何在Spring Security中编写自定义过滤器？

我希望每个请求接收一些信息，所以我认为不要为每个请求提供一个函数并分别从请求中获取这些信息，最好有一个过滤器。
所以每个请求都会通过这个过滤器，我就会得到我想要的。

问题是：如何编写自定义过滤器？
假设它不像任何预定义的 spring security 过滤器，并且它是全新的。

您可以使用标准 Java 过滤器。只需将其放在 web.xml 中的身份验证过滤器之后（这意味着它将稍后出现在过滤器链中，并在安全过滤器链之后被调用）。

public class CustomFilter implements Filter{

    @Override
    public void destroy() {
        // Do nothing
    }

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

            HttpServletRequest request = (HttpServletRequest) req;

            Authentication authentication = SecurityContextHolder.getContext().getAuthentication();

            Set<String> roles = AuthorityUtils.authorityListToSet(authentication.getAuthorities());
            if (roles.contains("ROLE_USER")) {
                request.getSession().setAttribute("myVale", "myvalue");
            }

            chain.doFilter(req, res);

    }

    @Override
    public void init(FilterConfig arg0) throws ServletException {
        // Do nothing
    }

}

web.xml 片段：

<!-- The Spring Security Filter Chain -->
<filter>
    <filter-name>springSecurityFilterChain</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>

<filter-mapping>
    <filter-name>springSecurityFilterChain</filter-name>
    <url-pattern>/*</url-pattern>
</filter-mapping>

<!-- Your filter definition -->
<filter>
    <filter-name>customFilter</filter-name>
    <filter-class>com.yourcompany.test.CustomFilter</filter-class>
</filter>
<filter-mapping>
    <filter-name>customFilter</filter-name>
    <url-pattern>/VacationsManager.jsp</url-pattern>
</filter-mapping>

您还可以添加将在成功登录后调用的处理程序（您需要扩展SavedRequestAwareAuthenticationSuccessHandler). 看这里这个怎么做。我认为这是更好的主意。

UPDATED:
或者您可以将此过滤器放在安全过滤器的末尾，如下所示：

<security:filter-chain-map>
    <sec:filter-chain pattern="/**"
            filters="
        ConcurrentSessionFilterAdmin, 
        securityContextPersistenceFilter, 
        logoutFilterAdmin, 
        usernamePasswordAuthenticationFilterAdmin, 
        basicAuthenticationFilterAdmin, 
        requestCacheAwareFilter, 
        securityContextHolderAwareRequestFilter, 
        anonymousAuthenticationFilter, 
        sessionManagementFilterAdmin, 
        exceptionTranslationFilter, 
        filterSecurityInterceptorAdmin,
        MonitoringFilter"/> <!-- Your Filter at the End -->
</security:filter-chain-map>

要拥有过滤器，您可以使用以下命令：

public class MonitoringFilter extends GenericFilterBean{
@Override
public void doFilter(ServletRequest request, ServletResponse response,
        FilterChain chain) throws IOException, ServletException {
    //Implement this Function to have your filter working
}