SpringBoot中的filter

Love The Way You Lie 2021-12-01 13:24 258阅读 0赞

在 Spring Boot 中使用 Filter 与前面的使用 Servlet 相似，根据 Filter 注册方式的不同，有两种使用方式。若使用的是 Servlet3.0+版本，则两种方式均可使用；若使用的是 Servlet2.5版本，则只能使用配置类方式。

## 1.注解方式 ##

若使用的是 Servlet3.0+版本，可以直接使用 Filter 的注解对 Filter 进行注册。其总步骤有  
两步：

*  在定义好的 Filter 上使用@WebFilter 注解
 *  在入口类上添加@ServletComponentScan 注解 —>需要写扫描的包

### 1.1创建springboot ###

### 1.2创建filter ###

自定义filter实现Filter接口

package com.example.demo.filter;
    
    import lombok.extern.slf4j.Slf4j;
    import javax.servlet.*;
    import javax.servlet.annotation.WebFilter;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    /** * @author Created by niugang on 2019/7/20/15:46 */
    @WebFilter("/*")
    @Slf4j
    public class AccesLogFilter implements Filter { 
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException { 
            log.info("AccesLogFilter init");
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 
            HttpServletRequest request = (HttpServletRequest) servletRequest;
            HttpServletResponse response = (HttpServletResponse) servletResponse;
            String requesturi = request.getRequestURI();
    
            log.info("Request URI:{}",requesturi);
            filterChain.doFilter(request,response);
        }
    
        @Override
        public void destroy() { 
            log.info("AccesLogFilter destroy");
        }
    }

### 1.3修改springboot启动入口 ###

package com.example.demo;
    
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.web.servlet.ServletComponentScan;
    
    @SpringBootApplication
    @ServletComponentScan(basePackages="com.example.demo.filter")
    public class DemoApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(DemoApplication.class, args);
        }
    
    }

## 2.配置方式 ##

若使用的是 Servlet2.5 版本，没有 Filter 注解，此时只能使用配置类方式。其总步骤有  
两步，与@ServletComponentScan 注解无关。

*  定义 Filter
 *  定义配置类

### 2.1创建工程 ###

### 2.2创建filter ###

package com.example.demo.filter;
    
    import lombok.extern.slf4j.Slf4j;
    import javax.servlet.*;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import java.io.IOException;
    
    /** * @author Created by niugang on 2019/7/20/15:46 */
    @Slf4j
    public class AccesLogFilter implements Filter { 
    
        @Override
        public void init(FilterConfig filterConfig) throws ServletException { 
            log.info("AccesLogFilter init");
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 
            HttpServletRequest request = (HttpServletRequest) servletRequest;
            HttpServletResponse response = (HttpServletResponse) servletResponse;
            String requesturi = request.getRequestURI();
    
            log.info("Request URI:{}",requesturi);
            filterChain.doFilter(request,response);
        }
    
        @Override
        public void destroy() { 
            log.info("AccesLogFilter destroy");
        }
    }

### 2.3修改配置类 ###

package com.example.demo;
    
    import com.example.demo.filter.AccesLogFilter;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.boot.web.servlet.FilterRegistrationBean;
    import org.springframework.context.annotation.Bean;
    
    @SpringBootApplication
    public class DemoApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(DemoApplication.class, args);
        }
    
        @Bean
        public FilterRegistrationBean<AccesLogFilter> registration() { 
            //创建filter
            AccesLogFilter accesLogFilter = new AccesLogFilter();
            //注册过滤器
            FilterRegistrationBean<AccesLogFilter> registration = new FilterRegistrationBean<>(accesLogFilter);
            //添加条件
            registration.addUrlPatterns("/*");
            return registration;
        }
    
    }

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