SpringBoot项目实战之HandlerInterceptorAdapter实现自定义拦截器

SpringBoot中提供了HandlerInterceptorAdapter适配器供我们自定义拦截器，可以拦截自定义或所有的请求做相应的处理。

HandlerInterceptorAdapter中共有四个方法：

preHandle ：在Controller方法被调用前执行
postHandle ：在Controller方法调用后执行
afterCompletion ：在整个请求处理完成之后执行
afterConcurrentHandlingStarted ：用来处理异步请求，当Controller中有异步请求方法的时候会触发该方法。

实现步骤

自定义拦截器

继承HandlerInterceptorAdapter，重写方法（在实际项目中，可以按照实际的业务重写方法，不需要重写全部四个方法）

/**
 * @Author zhangting
 * @Desc 自定义拦截器
 * @Date 2020/08/04
 **/
@Component
@Slf4j
public class MyInterceptor1 extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        log.info("----- preHandle(1) -----");
        return super.preHandle(request, response, handler);
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        log.info("----- postHandle(1) -----");
        super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        log.info("----- afterCompletion(1) -----");
        super.afterCompletion(request, response, handler, ex);
    }

    @Override
    public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        log.info("----- afterConcurrentHandlingStarted(1) -----");
        super.afterConcurrentHandlingStarted(request, response, handler);
    }
}

注册拦截器

实现WebMvcConfigurer，注册拦截器

/**
 * @Author zhangting
 * @Desc 注册拦截器
 * @Date 2020/08/04
 **/
@Configuration
public class InterceptorConfig implements WebMvcConfigurer {

    @Autowired
    private MyInterceptor1 myInterceptor1;


    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(myInterceptor1);
    }
}

上面实现的是自定义一个拦截器的情景，但是一般在实际项目中会需要自定义多个拦截器，那么这些拦截器的执行顺序又是如何确定的呢？拦截器内部的方法的执行顺序又是怎样的呢？

自定义多个拦截器

定义MyInterceptor2拦截器

/**
 * @Author zhangting
 * @Desc 自定义拦截器
 * @Date 2020/08/04
 **/
@Component
@Slf4j
public class MyInterceptor2 extends HandlerInterceptorAdapter {

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        log.info("----- preHandle(2) -----");
        return super.preHandle(request, response, handler);
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        log.info("----- postHandle(2) -----");
        super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        log.info("----- afterCompletion(2) -----");
        super.afterCompletion(request, response, handler, ex);
    }

    @Override
    public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        log.info("----- afterConcurrentHandlingStarted(2) -----");
        super.afterConcurrentHandlingStarted(request, response, handler);
    }
}

将自定义的MyInterceptor2拦截器注册到容器中

/**
 * @Author zhangting
 * @Desc 注册拦截器
 * @Date 2020/08/04
 **/
@Configuration
public class InterceptorConfig implements WebMvcConfigurer {

    @Autowired
    private MyInterceptor1 myInterceptor1;

    @Autowired
    private MyInterceptor2 myInterceptor2;

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(myInterceptor1);
        registry.addInterceptor(myInterceptor2);
    }
}