spring boot过滤器FilterRegistrationBean

有2种方式可以实现过滤器

1：通过FilterRegistrationBean实例注册

2：通过@WebFilter注解生效

这里选择第一种，因为第二种不能设置过滤器之间的优先级

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<Test1Filter> RegistTest1(){
        //通过FilterRegistrationBean实例设置优先级可以生效
        //通过@WebFilter无效
        FilterRegistrationBean<Test1Filter> bean = new FilterRegistrationBean<Test1Filter>();
        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<Test2Filter> RegistTest2(){
        //通过FilterRegistrationBean实例设置优先级可以生效
        //通过@WebFilter无效
        FilterRegistrationBean<Test2Filter> bean = new FilterRegistrationBean<Test2Filter>();
        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

如果把.addUrlPatterns();中拦截路径改成一样/test/*，则所有请求，都会触发2个过滤器，而且过滤器1永远在最先拦截