springBoot 中添加mvc攔截器interceptor

步驟:

    1.定義攔截器

    2.配置攔截器

正文:

1.定義攔截器,   實現 HandlerInterceptor 接口, 重寫接口的方法,在spring mvc 的攔截器中有三個方法

1)preHandle :進入controller前 

方法參數(HttpServletRequest request, HttpServletResponse response, Object handler)

重點是request和response,一般主要使用這兩個參數,比如從request中獲取特定的值,然後進行某些操作,或者修改response的響應頭之類的操作

2)postHandle :進入controller中,在return前

方法參數(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable ModelAndView modelAndView)

重點是modelAndView,此步驟主要是攔截modelAndView,在返回modelAndView前對modelAndView進行一些操作,比如添加或者刪除一些鍵值對

3)afterCompletion :出controller後,試圖解析前

方法參數(HttpServletRequest request, HttpServletResponse response, Object handler, @Nullable Exception ex)

重點是Exception ex,此步驟主要是攔截異常,對異常進行操作

示例:

public class PermissionInterceptor implements HandlerInterceptor {
    private Logger logger = LoggerFactory.getLogger(PermissionInterceptor.class);
    @Autowired
    private SsoProxy ssoProxy;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        //TODO 權限攔截
        String requestURI = request.getRequestURI();
//        logger.info("uri: = " + requestURI);
        return true;
    }
}

 2.配置攔截器

1)實例化自定義攔截器,並交由spring管理,

2)編寫配置類,並繼承  WebMvcConfigurationSupport 類,重寫 addInterceptors(InterceptorRegistry registry) 方法;

WebMvcConfigurationSupport 是springmvc的默認配置類,之前用WebMvcConfigurerAdapter,現WebMvcConfigurerAdapter已棄用,改用WebMvcConfigurationSupport,該類對springmvc的配置默認添加了一些實現,並提供了支持擴展的方法,使用者只需要繼承該類,然後補充自己的配置,例如添加攔截器,添加攔截器的方法:addInterceptors

@Configuration
//@Order(-1)
public class AppConfig extends WebMvcConfigurationSupport {

    @Bean
    public PermissionInterceptor getPermissionInterceptor(){
        return new PermissionInterceptor();
    }

    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(getPermissionInterceptor()).addPathPatterns("/**/api/**");
        super.addInterceptors(registry);
    }