SpringBoot自定义Filter的顺序

业务背景

项目中有一个jar包里面有别人封装好的一个Filter用来校验token ， 但是新功能不需要校验token， 但是又没有办法跳过 ， 因此需要我在这个jar包Filter执行之前 ， 在request中放入一个固定的token用来通过校验 。

最开始使用 @Order(0) 注解 试图将我写的Filter在jar包中的Filter之前执行 , 但是经过实验@Order(0) 并没有作用。需要在FilterRegistrationBean的时候设置order排序 。

package cn.com.baidu.filter;

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

@Configuration
public class FilterConfig{

    @Bean
    public FilterRegistrationBean Filter0(){
        FilterRegistrationBean filterRegistrationBean=new FilterRegistrationBean();
        filterRegistrationBean.setFilter(new PageFilter());//设置过滤器名称
        filterRegistrationBean.addUrlPatterns("/app/page/*");//配置过滤规则
        filterRegistrationBean.setOrder(0); //order的数值越小 则优先级越高
        return filterRegistrationBean;
    }

}

package cn.com.baidu.filter;

import org.springframework.stereotype.Component;
import java.io.IOException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
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.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;

@WebFilter(urlPatterns = "/app/page/*", filterName = "pageFilter")
@Component
public class PageFilter implements Filter {

    public PageFilter() {
    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req = (HttpServletRequest)request;
        // 因为request无法直接设置heafer , 因此需要对HttpServletRequest进行再封装
        MutableHttpServletRequest mutableRequest = new MutableHttpServletRequest(req);
        if(req.getHeader("token") == null) {
            // 如果请求头里面没有token , 就放入一个固定的token , 用来跳过jar包中的校验
            mutableRequest.putHeader("token", "固定的token");
        }
        chain.doFilter(mutableRequest, response);
    }

    public void init(FilterConfig filterConfig) throws ServletException {
        System.out.println("----pageFilter过滤器初始化----");
    }

    public void destroy() {
        System.out.println("----pageFilter过滤器销毁----");
    }
}

package cn.com.baidu.filter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletRequestWrapper;
import java.util.*;

class MutableHttpServletRequest extends HttpServletRequestWrapper {

    private final Map<String, String> customHeaders;

    public MutableHttpServletRequest(HttpServletRequest request){
        super(request);
        this.customHeaders = new HashMap<String, String>();
    }

    public void putHeader(String name, String value){
        this.customHeaders.put(name, value);
    }

    public String getHeader(String name) {
        String headerValue = customHeaders.get(name);
        if (headerValue != null){
            return headerValue;
        }
        return ((HttpServletRequest) getRequest()).getHeader(name);
    }

    public Enumeration<String> getHeaderNames() {
        Set<String> set = new HashSet<String>(customHeaders.keySet());
        Enumeration<String> e = ((HttpServletRequest) getRequest()).getHeaderNames();
        while (e.hasMoreElements()) {
            String n = e.nextElement();
            set.add(n);
        }
        return Collections.enumeration(set);
    }
}