简单了解SpringBoot过滤器及使用方式

过滤器简介

• 过滤器依赖Servlet容器，属于Servlet规范的一部分。
• 在实现上基于Servlet容器的函数回调，可以对几乎所有请求进行过滤。
• Filter的生命周期由Servlet容器管理。
  

过滤器执行流程

过滤器配置使用方式一

@Order(1) // 指定过滤器的执行顺序
@WebFilter(filterName = "CostTimeFilter", urlPatterns = "
  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
    this.url = filterConfig.getInitParameter("URL");
    System.out.println("Filter init...");
  }

  
  @Override
  public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
  	long start = System.currentTimeMillis();
    System.out.println(start + " Filter doFilter before...");
    filterChain.doFilter(servletRequest, servletResponse);
  	long end = System.currentTimeMillis();
    System.out.println(end + "Filter doFilter after...");
  }

  
  @Override
  public void destroy() {
    System.out.println("Filter destroy...");
  }
}

@RestController
public class IndexContoller {
  @RequestMapping("/query")
  public void query() throws Exception {
    System.out.println("IndexContoller query...");
  }
}

@SpringBootApplication
@ServletComponentScan // 扫描 Servlet 相关的组件
public class SpringBootFilterApplication {
  public static void main(String[] args) {
    SpringApplication.run(SpringBootFilterApplication.class, args);
  }
}

过滤器配置方式二

public class CostTimeFilter implements Filter {
  private String url;
  
  @Override
  public void init(FilterConfig filterConfig) throws ServletException {
    this.url = filterConfig.getInitParameter("URL");
    System.out.println("Filter init...");
  }

  
  @Override
  public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
  	long start = System.currentTimeMillis();
    System.out.println(start + " Filter doFilter before...");
    filterChain.doFilter(servletRequest, servletResponse);
  	long end = System.currentTimeMillis();
    System.out.println(end + "Filter doFilter after...");
  }

  
  @Override
  public void destroy() {
    System.out.println("Filter destroy...");
  }
}

@Configuration
public class FilterConfig {
  @Bean
  public FilterRegistrationBean registFilter() {
    FilterRegistrationBean registration = new FilterRegistrationBean();
    registration.setFilter(new CostTimeFilter());
    registration.addUrlPatterns("/*");
    registration.setName("CostTimeFilter");
    registration.setOrder(1);
    return registration;
  }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。