Spring Boot 自定義Filter

一、Filter功能

它使使用者可以改變一個 request和修改一個response. Filter 不是一個servlet,它不能産生一個response,它能夠在一個request到達servlet之前預處理request,也可以在離開 servlet時處理response.換種說法,filter其實是一個 “servlet chaining” (servlet 鍊).

一個Filter包括：

1）、在servlet被調用之前截獲;

2）、在servlet被調用之前檢查servlet request;

3）、根據需要修改request頭和request資料;

4）、根據需要修改response頭和response資料;

5）、在servlet被調用之後截獲.

二、自定義Filter

• 方法一：

1. 實作filter方法

   public class GlobalFilter implements Filter {
       @Override
       public void init(FilterConfig filterConfig) throws ServletException {
   
       }
   
       @Override
       public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
           HttpServletRequest request = (HttpServletRequest) servletRequest;
           String requestURI = request.getRequestURI();
           System.out.println(requestURI);
           filterChain.doFilter(request, servletResponse);
       }
   
       @Override
       public void destroy() {
   
       }
   }                

2. 加載Filter 配置

   @Configuration
   public class FilterConfig {
   
       @Bean
       public FilterRegistrationBean filterRegistration(){
           // 建立過濾器注冊類
           FilterRegistrationBean registration = new FilterRegistrationBean();
           // 添加自定義 過濾器
           registration.setFilter(globalFilter());
           // 設定過濾器的URL模式
           registration.addUrlPatterns("/*");
           //設定過濾器順序
           registration.setOrder(1);
           return registration;
       }
       @Bean
       public GlobalFilter globalFilter(){
           return new GlobalFilter();
       }
   }                    

• 方法二（推薦）
  1. 自定義MyFilter, 如果請求URI 包含

     my

     ， 則進行下一步處理

     @WebFilter(filterName = "myFilter", urlPatterns = "/*")
     public class MyFilter implements Filter {
     
         @Override
         public void init(FilterConfig filterConfig) throws ServletException {
             System.out.println("init...");
         }
     
         @Override
         public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
             HttpServletRequest request = (HttpServletRequest) servletRequest;
             String requestURI = request.getRequestURI();
             if(requestURI.contains("my")){
                 System.out.println("成功啦。。。, 請求URI是:" + requestURI);
             }
             filterChain.doFilter(request, servletResponse);
         }
     
         @Override
         public void destroy() {
             System.out.println("destroy...");
         }
     }                

  2. 在Application 啟動類 添加

     @ServletComponentScan

     注解

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

轉載于:https://www.cnblogs.com/XtsLife/p/11383842.html