SpringMVC实现文件上传和下载

ResponseEntity实现文件下载

使用ResponseEntity实现下载文件的功能

package com.lalala.controller;

import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpSession;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

@Controller
public class FileUploadAndDownloadController {
    @RequestMapping("/testDownload")
    public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws IOException {
        //获取ServletContext对象
        ServletContext servletContext = session.getServletContext();
        //获取服务器中文件的真实路径
        String realPath = servletContext.getRealPath("/static/img/1.jpg");
        //创建输入流
        InputStream is = new FileInputStream(realPath);
        //创建字节数组
        byte[] bytes = new byte[is.available()];
        //将流读到字节数组中
        is.read(bytes);
        //创建HttpHeaders对象设置响应头信息
        MultiValueMap<String, String> headers = new HttpHeaders();
        //设置要下载方式以及下载文件的名字
        headers.add("Content-Disposition", "attachment;filename=1.jpg");
        //设置响应状态码
        HttpStatus statusCode = HttpStatus.OK;
        //创建ResponseEntity对象
        ResponseEntity<byte[]> responseEntity = new ResponseEntity<>(bytes, headers, statusCode);
        //关闭输入流
        is.close();
        return responseEntity;
    }
}

实现文件上传

添加依赖：

<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.1</version>
</dependency>

在springmvc.xml中配置文件上传解析器：

<!-- 配置文件上传解析器，将上传的文件封装为MultipartFile -->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>

controller如下：

package com.lalala.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletContext;
import javax.servlet.http.HttpSession;
import java.io.File;
import java.io.IOException;
import java.util.UUID;

@Controller
public class FileUploadAndDownloadController {
    @RequestMapping("/testUpload")
    public String testUp(MultipartFile photo, HttpSession session) throws IOException {
        //获取上传的文件的文件名
        String fileName = photo.getOriginalFilename();
        //获取上传文件的后缀名
        String suffixName = fileName.substring(fileName.lastIndexOf("."));
        //将UUID作为文件名
        fileName = UUID.randomUUID().toString() + suffixName;
        //获取服务器中photo目录的路径
        ServletContext servletContext = session.getServletContext();
        String photoPath = servletContext.getRealPath("photo");
        File file = new File(photoPath);
        if(!file.exists()){
            file.mkdir();
        }
        String finalPath = photoPath + File.separator + fileName;
        //实现上传功能
        photo.transferTo(new File(finalPath));
        return "success";
    }
}