springboot 过滤器FilterRegistrationBean详解

一：基础知识

1.通过FilterRegistrationBean实例注册，该方法能够设置过滤器之间的优先级

2.为了演示优先级，这里创建2个测试过滤器类：Test1Filter、Test2Filter

通过实现javax.servlet.Filter接口，覆盖其doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)方法，决定拦截或放行

public class Test1Filter implements Filter {

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        // TODO Auto-generated method stub
        HttpServletRequest request=(HttpServletRequest)arg0;
        System.out.println("自定义过滤器filter1触发,拦截url:"+request.getRequestURI());
        arg2.doFilter(arg0,arg1);
    }

}

public class Test2Filter implements Filter {

    @Override
    public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2)
            throws IOException, ServletException {
        // TODO Auto-generated method stub
        HttpServletRequest request=(HttpServletRequest)arg0;
        System.out.println("自定义过滤器filter2触发,拦截url:"+request.getRequestURI());
        arg2.doFilter(arg0,arg1);
    }

}

通过在springboot的configuration中配置不同的FilterRegistrationBean实例，来注册自定义过滤器

这里创建一个configuration类

import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.example.demo.filter.Test1Filter;
import com.example.demo.filter.Test2Filter;

@Configuration
public class DemoConfiguration {

    @Bean
    public FilterRegistrationBean RegistTest1(){
        //通过FilterRegistrationBean实例设置优先级可以生效
        //通过@WebFilter无效
        FilterRegistrationBean bean = new FilterRegistrationBean();
        bean.setFilter(new Test1Filter());//注册自定义过滤器
        bean.setName("flilter1");//过滤器名称
        bean.addUrlPatterns("/*");//过滤所有路径
        bean.setOrder(1);//优先级，最顶级
        return bean;
    }
    @Bean
    public FilterRegistrationBean RegistTest2(){
        //通过FilterRegistrationBean实例设置优先级可以生效
        //通过@WebFilter无效
        FilterRegistrationBean bean = new FilterRegistrationBean();
        bean.setFilter(new Test2Filter());//注册自定义过滤器
        bean.setName("flilter2");//过滤器名称
        bean.addUrlPatterns("/test/*");//过滤所有路径
        bean.setOrder(6);//优先级，越低越优先
        return bean;
    }
}

其中

1第一个bean拦截所有路径，而第二个只拦截/test/*路径

2第一个bean优先级设置了1，而第二个设置了6，越低越优先，所以过滤器1应该在过滤器2前面拦截

运行springboot，访问/test/*请求如下图，再访问/v请求如下图只拦截了过滤器1，而过滤器2路径不匹配

以上原文地址：spring boot过滤器FilterRegistrationBean - 稚语希听 - 博客园

 二：实战练习

1.管理员过滤器

package com.imooc.mall.filter;

import com.imooc.mall.common.ApiRestResponse;
import com.imooc.mall.common.Constant;
import com.imooc.mall.exception.ImoocMallExceptionEnum;
import com.imooc.mall.model.pojo.Category;
import com.imooc.mall.model.pojo.User;
import com.imooc.mall.service.UserService;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;
import javax.servlet.http.HttpSession;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;

/**
 * 描述：     管理员校验过滤器
 */
public class AdminFilter implements Filter {

    @Autowired
    UserService userService;

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

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse,
            FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpSession session = request.getSession();
        User currentUser = (User) session.getAttribute(Constant.IMOOC_MALL_USER);
        if (currentUser == null) {
            PrintWriter out = new HttpServletResponseWrapper(
                    (HttpServletResponse) servletResponse).getWriter();
            out.write("{\n"
                    + "    \"status\": 10007,\n"
                    + "    \"msg\": \"NEED_LOGIN\",\n"
                    + "    \"data\": null\n"
                    + "}");
            out.flush();
            out.close();
            return;
        }
        //校验是否是管理员
        boolean adminRole = userService.checkAdminRole(currentUser);
        if (adminRole) {
            filterChain.doFilter(servletRequest, servletResponse);
        } else {
            PrintWriter out = new HttpServletResponseWrapper(
                    (HttpServletResponse) servletResponse).getWriter();
            out.write("{\n"
                    + "    \"status\": 10009,\n"
                    + "    \"msg\": \"NEED_ADMIN\",\n"
                    + "    \"data\": null\n"
                    + "}");
            out.flush();
            out.close();
        }
    }

    @Override
    public void destroy() {

    }
}

2.管理员过滤器配置

package com.imooc.mall.config;

import com.imooc.mall.filter.AdminFilter;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

/**
 * 描述：     Admin过滤器的配置
 */
@Configuration
public class AdminFilterConfig {

    @Bean
    public AdminFilter adminFilter() {
        return new AdminFilter();
    }

    @Bean(name = "adminFilterConf")
    public FilterRegistrationBean adminFilterConfig() {
        FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();
        filterRegistrationBean.setFilter(adminFilter());
        filterRegistrationBean.addUrlPatterns("/admin/category/*");
        filterRegistrationBean.addUrlPatterns("/admin/product/*");
        filterRegistrationBean.addUrlPatterns("/admin/order/*");
        filterRegistrationBean.setName("adminFilterConf");
        return filterRegistrationBean;
    }
}