Spring Boot整合Filter

客官°小女子只卖身不卖艺 2023-06-03 14:57 17阅读 0赞

### Spring Boot整合Filter ###

*  一、原有web.xml中Filter配置
 *  二、使用注解扫描完成Filter组件注册
 *  三、使用方法完成Filter组件注册

假设对一个servlet请求 /first 进行拦截过滤。

# 一、原有web.xml中Filter配置 #

<filter>
    	<filter-name>FirstFilter</filter-name>
    	<filter-class>com.tumbler.filter.FirstFilter</filter-class>
    </filter>
    <filter-mapping>
    	<filter-name>FirstFilter</filter-name>
    	<url-pattern>/first</url-pattern>
    </filter-mapping>

# 二、使用注解扫描完成Filter组件注册 #

1.  首先创建Servlet，直接拿整合Servlet中的第一种FirstServlet

/** * User：tumbler * Desc：SpringBoot整合Filter备用Servlet */
    @WebServlet(name = "FirstServlet", urlPatterns = "/first")
    public class FirstServlet extends HttpServlet { 
    
        @Override
        public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException { 
            System.out.println("This is First Servlet");
        }
    }

1.  创建Filter  
    主要使用注解@WebFilter()，其中urlPatterns = 一个字符串数组，代表可以拦截多种请求，例如urlPatterns = \{"*.do", "*.jsp"\}，这里只拦截FirstServlet中的 /first

/** * User：tumbler * Desc：SpringBoot整合Filter 方式一：使用注解扫描完成Filter组价注册 * * * @WebFilter(filterName = "FirstFilter", urlPatterns = {"*.do", "*.jsp"}) */
    @WebFilter(filterName = "FirstFilter", urlPatterns = "/first")
    public class FirstFilter implements Filter { 
        @Override
        public void init(FilterConfig filterConfig) throws ServletException { 
    
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 
            System.out.println("进入Filter");
            filterChain.doFilter(servletRequest, servletResponse);
            System.out.println("放行Filter");
        }
    
        @Override
        public void destroy() { 
    
        }
    }

1.  编写启动类，加上注解@ServletComponentScan

@SpringBootApplication
    @ServletComponentScan
    public class SpringBootFilterApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(SpringBootFilterApplication.class, args);
        }
    
    }

1.  启动项目并进行测试  
    浏览器输入http://localhost:8080/first, 观察控制台，Filter已经执行：

进入Filter
    This is First Servlet
    放行Filter

# 三、使用方法完成Filter组件注册 #

1.  首先准备要拦截的Servlet

/** * User：tumbler * Desc：SpringBoot整合Filter备用Servlet */
    public class SecondServlet extends HttpServlet { 
        @Override
        public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException { 
            System.out.println("This is second Servlet");
        }
    }

1.  创建SecondFilter，不使用注解

/** * User：tumbler * Desc：SpringBoot整合Filter 方式二：通过方法完成Filter组件注册 */
    public class SecondFilter implements Filter { 
        @Override
        public void init(FilterConfig filterConfig) throws ServletException { 
    
        }
    
        @Override
        public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException { 
            System.out.println("进入SecondFilter");
            filterChain.doFilter(servletRequest, servletResponse);
            System.out.println("放行SecondFilter");
        }
    
        @Override
        public void destroy() { 
    
        }
    }

1.  编写启动类，使用@Bean注解通过方法完成Filter和Servlet的注册， 类上不使用@ServletComponentScan

@SpringBootApplication
    public class SpringBootFilterApplication { 
    
        public static void main(String[] args) { 
            SpringApplication.run(SpringBootFilterApplication.class, args);
        }
    
        /** * 注册Servlet * @return Servlet */
        @Bean
        public ServletRegistrationBean servletRegistrationBean() { 
            ServletRegistrationBean servletRegistrationBean = new ServletRegistrationBean(new SecondServlet());
            servletRegistrationBean.addUrlMappings("/second");
            return servletRegistrationBean;
        }
    
        /** * 注册Filter * @return Filter */
        @Bean
        public FilterRegistrationBean filterRegistrationBean() { 
            FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(new SecondFilter());
            //filterRegistrationBean.addUrlPatterns(new String[]{"*.do", "*.jsp"});
            filterRegistrationBean.addUrlPatterns("/second");
            return filterRegistrationBean;
        }
    }

1.  启动项目并测试  
    浏览器输入http://localhost:8080/second, 观察控制台，Filter已经执行：

进入SecondFilter
    This is second Servlet
    放行SecondFilter