@Component
//定義攔截器類，實現(xiàn)HandlerInterceptor接口
//注意當前類必須受Spring容器控制
public class ProjectInterceptor implements HandlerInterceptor {
    @Override
    //原始方法調(diào)用前執(zhí)行的內(nèi)容
    //返回值類型可以攔截控制的執(zhí)行，true放行，false終止
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle...");
        return true;
    }
 
    @Override
    //原始方法調(diào)用后執(zhí)行的內(nèi)容
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle...");
    }
 
    @Override
    //原始方法調(diào)用完成后執(zhí)行的內(nèi)容
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        System.out.println("afterCompletion...");
    }
}

2、定義配置類，繼承WebMvcConfigurationSupport，實現(xiàn)addInterceptor（注意掃描加載配置）

@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport {
 
    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        。。。
    }
}

3、添加攔截器并設(shè)定攔截的訪問路徑，路徑可以通過可變參數(shù)設(shè)置多個

@Configuration
public class SpringMvcSupport extends WebMvcConfigurationSupport {
    @Autowired
    private ProjectInterceptor projectInterceptor;
 
    @Override
    protected void addInterceptors(InterceptorRegistry registry) {
        //配置攔截器
        registry.addInterceptor(projectInterceptor).addPathPatterns("/books","/books/*");
    }
}

4、使用標準接口WebMvcConfigurer簡化開發(fā)（注意：侵入式較強）

@Configuration
@ComponentScan({"com.itheima.controller"})
@EnableWebMvc
//實現(xiàn)WebMvcConfigurer接口可以簡化開發(fā)，但具有一定的侵入性
public class SpringMvcConfig implements WebMvcConfigurer {
    @Autowired
    private ProjectInterceptor projectInterceptor;
 
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        //配置攔截器
        registry.addInterceptor(projectInterceptor).addPathPatterns("/books","/books/*");
    }
}

攔截器執(zhí)行流程