文件的上传与下载

文件上传下载案例

1、文件上传

1.1 导入依赖

<!-- 文件上传相关依赖 -->
<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.4</version>
</dependency>
<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.3</version>
</dependency>

1.2 springmvc配置文件中增加文件解析器

<!-- 文件上传解析器，bean的id必须叫 multipartResolver-->
<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
    <property name="maxUploadSize" value="10240000"></property>
</bean>

1.3 handler

@RestController
public class UploadController {

    @RequestMapping("/upload")
    public String upload(@RequestParam("img") MultipartFile img, HttpSession session){
        try {
            String originalFilename = img.getOriginalFilename();
            String extName = originalFilename.substring(originalFilename.lastIndexOf("."));  //.jpg
    
            String realPath = session.getServletContext().getRealPath("/files");
            System.out.println("-->" + realPath);
    
            String uuid = UUID.randomUUID().toString().replaceAll("-", "");
    
            File dest = new File(realPath, uuid.concat(extName));
            img.transferTo(dest);
        } catch (IOException e) {
            e.printStackTrace();
        }
    
        return "success";
    }


}

1.4 测试

• 上传成功后，在realPath目录下有一个文件。

2、文件下载

2.1 页面

<a href="download?name=gzmn.jpg">下载gzmn.jpg</a>

2.2 Controller

package com.qf.java2007.web.controller;


import org.apache.commons.io.IOUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.FileInputStream;

import java.io.OutputStream;

/**
 * @author ghy
 * @version 1.0
 */
@RestController
public class DownloadController {

    @RequestMapping("/download")
    public void download(String name, HttpSession session, HttpServletResponse response){
        try {
            //通过文件名获取到服务器上的真实文件
            String filePath = session.getServletContext().getRealPath("/files/" + name);
            FileInputStream in = new FileInputStream(filePath);
            //告知浏览器以附件的形式去打开这个资源
            response.addHeader("content-disposition", "attachment;filename=" + name);
            OutputStream out = response.getOutputStream();
            IOUtils.copy(in, out);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
    
}