springboot-添加过滤器

过滤器一次，顾名思义，过滤一些东西等等。那么怎么实现呢，具体代码如下

首先肯定需要建一个filter的包，创建一个过滤类实现filter接口，用来过滤

package com.gateway.filter;

import java.io.IOException;

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 org.springframework.stereotype.Component;

@Component
public class UserFilter implements Filter {

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {
        // TODO Auto-generated method stub
        
    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain chain)
            throws IOException, ServletException {
            HttpServletRequest request=(HttpServletRequest) servletRequest;
        
            HttpServletResponse response=(HttpServletResponse) servletResponse;
            
            System.out.println("过滤器实现");
            
            chain.doFilter(request, response);
    }

    @Override
    public void destroy() {
        // TODO Auto-generated method stub
        
    }

}

然后在启动类中将该过滤类加载进去

@Bean
     public FilterRegistrationBean filterRegistrationBean(){
        
        FilterRegistrationBean  filterRegistrationBean=new FilterRegistrationBean();
        
        List<String>urlPatterns=new ArrayList<String>();
        
        filterRegistrationBean.setFilter(new UserFilter());
        
        urlPatterns.add("/user/touser");
        
        filterRegistrationBean.setUrlPatterns(urlPatterns);
        return filterRegistrationBean;
    }

由上可知，我们过滤的路径是/user/touser,那么过滤器和拦截器先进谁呢，debug测试即可得知，当路径/user/touser过来，先进入过滤器完成之后在进入拦截器，最后执行 完成之后进入controller