SSM:拦截器&model&文件的上传和下载

public class MyInterceptor implements HandlerInterceptor {
    public boolean  preHandle(HttpServletRequest request, HttpServletResponse response, Object   handler) throws Exception{
        System.out.println("===========处理前==========");
        return false; //   当return false 不会执行之后的
    }
    //日志
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object   handler, ModelAndView modelAndView) throws Exception{
        System.out.println("===========处理后==========");
    }
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object   handler, Exception  ex) throws Exception{
        System.out.println("===========清理 ==========");
    }
}

<!--拦截器 的配置 -->
    <mvc:interceptors>
        <mvc:interceptor>
<!--            包括这个 请求 下面 的 所有请求 -->
<!--            /**    文件下所有-->
<!--            /*    文件下一个-->
            <mvc:mapping path="/**"/>
            <bean class="com.youren.interceptor.MyInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

package com.youren.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
@Controller
public class ModelTest {
    @RequestMapping("/hello")
    public String test(ModelAndView model) {
        // 业务代码
        String result = "HelloSpringMVC";
        model.addObject("msg", result);
        return "forward:/WEB-INF/jsp/test.jsp";
   //       return  "redirect:index.jsp";
    }
}

<dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>4.0.1</version>
    </dependency>
    <dependency>
        <groupId>commons-fileupload</groupId>
        <artifactId>commons-fileupload</artifactId>
        <version>1.3.3</version>
    </dependency>

<!--    the file upload configuration-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<!--   request encoding   default is ISO-8859-1     -->
        <property name="defaultEncoding" value="utf-8" />
<!--      max    10485760=10m   -->
        <property name="maxUploadSize" value="10485760"/>
        <property name="maxInMemorySize" value="40960"/>
    </bean>

@RestController
public class fileController {
    @RequestMapping("/upload")
    public String upload(@RequestParam("file")CommonsMultipartFile file, HttpServletRequest request)  throws IOException {
        // get the filename
        String uploadFileName = file.getOriginalFilename();
//        judge
        if("".equals(uploadFileName)){
            return "redirect:/index.jsp";
        }
        System.out.println("the upload filename  is:"+uploadFileName);
//        save the file path
        String path= request.getServletContext().getRealPath("/upload");
//        if  the path is not existing create it
        File realPath= new File(path);
        if(!realPath.exists()){
            realPath.mkdirs();
        }
        System.out.println("the upload file path is :"+realPath);
        InputStream inputStream = file.getInputStream();    // input stream
        OutputStream outputStream =new FileOutputStream(new File(realPath,uploadFileName));
//        读取写出
        int len = 0;
        byte[] buffer= new byte[1024];
        while ((len=inputStream.read(buffer))!=-1){
            outputStream.write(buffer,0,len);
            outputStream.flush();
        }
        outputStream.close();
        inputStream.close();
        return "redirect:/index.jsp";
    }
}