SpringBoot | SpringBoot多种 Filter过滤器 配置方式

一、注解 @WebFilter+@ServletComponentScan

1. @ServletComponentScan

需要在启动类/配置类 使用 @ServletComponentScan 默认扫描启动类所在的包以及子包

@ServletComponentScan 的作用:

• 扫描指定包下使用 @WebServlet 注解的类 自动注册
• 扫描指定包下使用 @WebFilter 注解的类 自动注册
• 扫描指定包下使用 @WebListener 注解的类 自动注册

@SpringBootApplication
@ServletComponentScan//扫描 webfilter 注解 自动注册
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

2. @WebFilter

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

    @Autowired
    private RedisService<String> redisService;

    @Override
    public void init(FilterConfig filterConfig) {
        if (redisService == null) {
            BeanFactory factory = WebApplicationContextUtils.getRequiredWebApplicationContext(filterConfig.getServletContext());
            redisService = factory.getBean(RedisService.class);
        }
    }

    @Override
    public void doFilter(ServletRequest request, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        request.setCharacterEncoding("UTF-8");
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        //这里填写你允许进行跨域的主机ip（正式上线时可以动态配置具体允许的域名和IP）
        //response.setHeader("Access-Control-Allow-Origin", passip);
        //Access-Control-Max-Age 用于 CORS 相关配置的缓存
        response.setContentType("html/text;charset=UTF-8");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with,authorization,Content-Type,farm,store");
        response.setHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, PATCH, DELETE, OPTIONS, TRACES");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        filterChain.doFilter(request, response);
    }

    @Override
    public void destroy() {
    }
}

二、注解 @Component

/**
 * 跨域请求处理 filter
 */
@Component
@Order(value = Ordered.HIGHEST_PRECEDENCE)//这是跨域优先级
public class Crossfilter implements Filter {


    @Override
    public void doFilter(ServletRequest request, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest) request;
        request.setCharacterEncoding("UTF-8");
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        //这里填写你允许进行跨域的主机ip（正式上线时可以动态配置具体允许的域名和IP）
        //response.setHeader("Access-Control-Allow-Origin", passip);
        //Access-Control-Max-Age 用于 CORS 相关配置的缓存
        response.setContentType("html/text;charset=UTF-8");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "x-requested-with,authorization,Content-Type,farm,store");
        response.setHeader("Content-Type", "application/x-www-form-urlencoded; charset=UTF-8");
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "GET, HEAD, POST, PUT, PATCH, DELETE, OPTIONS, TRACES");
        response.setHeader("Access-Control-Allow-Credentials", "true");
        filterChain.doFilter(request, response);
    }

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
    }

    @Override
    public void destroy() {
    }
}

三、JavaConfig 方式( 推荐 )

使用 @Bean 的方式创建Filter
推荐理由: 更加有效的管理filter 既能控制执行顺序 又能控制 过滤请求路径

/**
 * Filter 配置类
 *
 * @Author su
 * @Date 2022/6/23 9:41
 */
@Configuration
public class FilterConfig {

    @Bean
    public FilterRegistrationBean filterRegistrationBean(){
        FilterRegistrationBean<Filter> filterFilterRegistrationBean = new FilterRegistrationBean<>();
        filterFilterRegistrationBean.setFilter(new Crossfilter());
        filterFilterRegistrationBean.setOrder(1);//执行的顺序
        filterFilterRegistrationBean.addUrlPatterns("/*");
        return filterFilterRegistrationBean;
    }
}

四、 总结注意

• 使用 外部 tomcat 启动 需要重写 init() destroy() 方法 否则会启动失败.
• 使用 外部 tomcat 启动 注入对象的会 需要特殊处理 处理方式看我 init() 方法中的操作
• 使用@WebFilter 无法使用 @Ordered /Ordered 进行执行顺序控制
• 使用 @Component 无法控制 请求过滤路径

需要控制Filter 执行顺序的 点击跳转 https://blog.csdn.net/qq825478739/article/details/125350219

Filter 顺序控制跳转