spring MVC拦截器

2022年07月03日23:53:09 科技 1878

核心接口

HandlerInteceptor

HandlerInteceptor主要方法

1、boolean preHandle(): Controller方法执行前进行预处理，返回true，则继续执行方法处理，否则终止方法的继续处理；不进入postHandle、afterCompletion。

2、void postHandle()：所有拦截器的preHandle调用结束后且返回true，并且controller方法执行结束后视图渲染之前才进行调用。顺序则跟order指定的相反。

3、void afterCompletion()：所有拦截器的preHandle调用结束后且返回true，所有postHandle执行结束，视图渲染结束之后执行

使用

1、首先编写拦截器逻辑实现类

package com.falcon.design.interceptor;

import lombok.extern.slf4j.Slf4j;
import org.springframework.util.StopWatch;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@Slf4j
public class DesignIntercept implements HandlerInterceptor {

    private ThreadLocal<StopWatch> stopWatchThreadLocal = new ThreadLocal<>();

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        StopWatch stopWatch = new StopWatch();
        stopWatchThreadLocal.set(stopWatch);
        stopWatch.start();
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        stopWatchThreadLocal.get().stop();
        stopWatchThreadLocal.get().start();
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        StopWatch sw = stopWatchThreadLocal.get();
        String method = handler.getClass().getSimpleName();
        if(handler instanceof HandlerMethod){
            String beanType = ((HandlerMethod) handler).getBeanType().getName();
            String methodName = ((HandlerMethod) handler).getMethod().getName();
            method = beanType + "." + methodName;
        }
        log.info("{}, {}, {}, {}; {}ms, {}ms, {}ms",request.getRequestURI(),method,
                response.getStatus(), ex==null ? "-" : ex.getClass().getSimpleName(),
                sw.getTotalTimeMillis(), sw.getTotalTimeMillis()-sw.getLastTaskTimeMillis(), sw.getLastTaskTimeMillis());
        stopWatchThreadLocal.remove();
    }
}

2、在私有的webMvcConfiguer中通过addInterceptor方法加入到拦截容器

package com.falcon.design.config;

import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import com.falcon.design.interceptor.DesignIntercept;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.MediaType;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

import java.util.ArrayList;
import java.util.List;


@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

    public HttpMessageConverters FastJsonHttpMessageConverters(){
        return new HttpMessageConverters( stringHttpMessageConverter(), new FastJsonHttpMessageConvertExtension());
    }

    public class FastJsonHttpMessageConvertExtension extends FastJsonHttpMessageConverter{
        FastJsonHttpMessageConvertExtension(){
            List<MediaType> mediaTypes = new ArrayList<>();
            mediaTypes.add(MediaType.APPLICATION_JSON);
            setSupportedMediaTypes(mediaTypes);
        }
    }

    public StringHttpMessageConverter stringHttpMessageConverter(){
        return new StringHttpMessageConverter();
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(new DesignIntercept()).addPathPatterns("/design/**");
    }
}

3、测试