filter过滤器

filter过滤器实现方式有两种：

• 过滤器实现方式一
  第一步：创建MyFilter类实现Filter接口

  package com.example.lambda.annotation;
  
  import lombok.extern.slf4j.Slf4j;
  import org.springframework.core.annotation.Order;
  
  import javax.servlet.*;
  import javax.servlet.annotation.WebFilter;
  import java.io.IOException;
  
  /**
   * @author: WZ
   * @create: 2022-10-19 09:04
   * @description: 过滤器实现方式1
   **/
  @Component
  @Slf4j
  public class MyFilter implements Filter {
  
      @Override
      public void init(FilterConfig filterConfig) throws ServletException {
          log.info("---------------【{}】创建...", this.getClass().getSimpleName());
      }
  
      @Override
      public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
          log.info("---------------【{}】执行...", this.getClass().getSimpleName());
          filterChain.doFilter(servletRequest, servletResponse);
      }
  
      @Override
      public void destroy() {
          log.info("---------------【{}】销毁", this.getClass().getSimpleName());
      }
  }
  
  

  第二步：创建MyFilterConfig配置类 向spring容器注册filter

  
  package com.example.lambda.annotation;
  
  import org.springframework.boot.web.servlet.FilterRegistrationBean;
  import org.springframework.context.annotation.Bean;
  import org.springframework.context.annotation.Configuration;
  
  import javax.annotation.Resource;
  import javax.servlet.Filter;
  
  /**
   * @author: WZ
   * @create: 2022-10-19 09:15
   * @description: 向spring容器注册filter
   **/
  
  @Configuration
  public class MyFilterConfig {
      @Resource
      private MyFilter myFilter;
  
      @Bean
      public FilterRegistrationBean testFilterRegistration() {
          //创建要向指定的ServletRegistrationBeans注册的新FilterRegistrationBean实例
          FilterRegistrationBean registration = new FilterRegistrationBean(myFilter);
          //添加过滤器将针对的URL模式
          registration.addUrlPatterns("/test/*");
          //设置注册bean的名称
          registration.setName("myFilter");
          //设置注册bean的顺序 值越大越靠后执行
          registration.setOrder(1);
          return registration;
      }
  }
  
  

• 过滤器实现方式二
  通过@WebFilter注解实现

  package com.example.lambda.annotation;
  
  import lombok.extern.slf4j.Slf4j;
  import org.springframework.core.annotation.Order;
  
  import javax.servlet.*;
  import javax.servlet.annotation.WebFilter;
  import java.io.IOException;
  
  /**
   * @author: WZ
   * @create: 2022-10-19 09:04
   * @description: 过滤器实现方式1
   **/
  //@Component 无需添加此注解，在启动类添加@ServletComponentScan注解后，会自动将带有@WebFilter的注解进行注入！
  @WebFilter(urlPatterns = "/test/*", filterName = "myFilter")
  //需要在SpringBootApplication上添加
  //@ServletComponentScan Servlet、Filter、Listener 可以直接通过 @WebServlet、@WebFilter、@WebListener 注解自动注册，无需其他代码
  @Order(1) //指定过滤器的执行顺序,
  @Slf4j
  public class MyFilter implements Filter {
  
      @Override
      public void init(FilterConfig filterConfig) throws ServletException {
          log.info("---------------【{}】创建...", this.getClass().getSimpleName());
      }
  
      @Override
      public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
          log.info("---------------【{}】执行...", this.getClass().getSimpleName());
          filterChain.doFilter(servletRequest, servletResponse);
      }
  
      @Override
      public void destroy() {
          log.info("---------------【{}】销毁", this.getClass().getSimpleName());
      }
  }