自定义方法限制上传图片（文件）的格式

水深无声 2022-04-16 00:37 296阅读 0赞

import org.apache.catalina.core.ApplicationPart;
    import org.springframework.web.servlet.HandlerInterceptor;
    import org.springframework.web.servlet.ModelAndView;
    
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.Part;
    import java.io.IOException;
    import java.util.Collection;
    import java.util.List;
    
    /**
     * @author zlw
     * @date 2018/11/13
     * @description
     */
    public class UploadFileInterceptor implements HandlerInterceptor {
    
        /** 允许上传的图片格式 */
        private static final String[] PERMITTED_IMAGE_TYPE = {"jpg", "png"};
    
        @Override
        public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
            //在请求处理之前进行调用（Controller方法调用之前）
            // 只有返回true才会继续向下执行，返回false取消当前请求
            return isImageQuealified(httpServletRequest);
        }
    
        @Override
        public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
            //请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后）
        }
    
        @Override
        public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
            //在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）
        }
    
        /**
         * 注意：此方法不具有普适性，只适用于http的post请求，且第一个参数为MultipartFile类型的
         * 校验所拦截的请求中上传的图片的格式是否合格
         */
        private boolean isImageQuealified (HttpServletRequest httpServletRequest) throws IOException, ServletException {
    
            Collection<Part> parts =  httpServletRequest.getParts();
            String fileType = "";
    
            if (null != parts && parts.size() > 0) {
                List list = (List) parts;
                ApplicationPart partZero = (ApplicationPart) list.get(0);
                String zeroName = partZero.getSubmittedFileName();
                String trimedName = zeroName.trim();
                int lastDotIndex = trimedName.lastIndexOf(".");
                fileType = trimedName.substring(lastDotIndex + 1, trimedName.length());
            }
    
            for (String s : PERMITTED_IMAGE_TYPE) {
                if (fileType.equalsIgnoreCase(s)) {
                    return true;
                }
            }
            return false;
    
        }
    
    
    }

import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
    import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
    
    
    
    /**
     * 拦截器注册配置
     */
    @Configuration
    public class WebMvcConfig extends WebMvcConfigurerAdapter {
    
    
    
        /**
         * 上传的图片校验拦截器，将拦截器作为bean写入配置中，不能直接new,否则拦截器无法注入服务
         */
        @Bean
        public UploadFileInterceptor uploadFileInterceptor() {
            return new UploadFileInterceptor();
        }
    
        /**
         * 拦截器注册
         *
         * @param registry
         */
        @Override
        public void addInterceptors(InterceptorRegistry registry) {
            // 多个拦截器组成一个拦截器链
            // addPathPatterns 用于添加拦截规则
            // excludePathPatterns 用户排除拦截
            registry.addInterceptor(loginInterceptor());
            registry.addInterceptor(uploadFileInterceptor()).addPathPatterns("/pacs/uploadScreenShot");//对上传图片接口拦截，做图片格式校验
        }
    }