案例14 Spring MVC文件上传案例

基于Spring MVC实现文件上传：

1. 使用commons-fileupload实现上传文件到本地目录。

2. 实现上传文件到阿里云OSS和从阿里云OSS下载文件到本地。

1. 创建项目

选择Maven快速构建web项目，项目名称为case14-springmvc03。

​

2. 配置Maven依赖

  4.0.0
  com.wfit.springmvc
  springmvc02
  1.0-SNAPSHOT
  war

  
    UTF-8
    1.8
    1.8
  

  
    
    
      org.springframework
      spring-webmvc
      5.3.8
    
    
    
      javax.servlet
      javax.servlet-api
      3.1.0
      provided
    
    
    
      commons-fileupload
      commons-fileupload
      1.4
    
    
    
      com.aliyun.oss
      aliyun-sdk-oss
      3.15.1
    
  

3. 创建Spring MVC配置文件

src.main.resources目录下创建spring-mvc.xml。

4. 配置web.xml

  
  
    encodingFilter
    org.springframework.web.filter.CharacterEncodingFilter
    
      encoding
      utf-8
    
  
  
    encodingFilter
    /*
  
  
  
    dispatcherServlet
    org.springframework.web.servlet.DispatcherServlet
    
    
      contextConfigLocation
      classpath:spring-mvc.xml
    
    
    1
  
  
    dispatcherServlet
    
    /
  

5. 创建UploadController类

在src.main.java.com.wfit.upload目录下创建UploadController类，实现文件上传。

@Controller
@RequestMapping("/upload")
public class UploadController {
    /**
     * 文件上传
     * @param file
     * @return
     */
    @PostMapping("/upload")
    @ResponseBody
    public String upload(MultipartFile file) throws IOException {
        //验证文件是否为空
        if(ObjectUtils.isEmpty(file) || file.getSize() <=0){
            return "file is empty";
        }
        //创建上传文件位置
        File uploadDir = new File("D:\\upload");
        //获取文件名
        String fileName = file.getOriginalFilename();
        //创建目标文件
        File desFile = new File(uploadDir,fileName);
        //执行上传操作
        file.transferTo(desFile);
        return "success";
    }
}

6. 创建OssController类

在src.main.java.com.wfit.upload目录下创建OssController类，实现上传文件到阿里云OSS和从阿里云OSS下载文件到本地。

@Controller
@RequestMapping("/oss")
public class OssController {

    //访问OSS的域名
    private static String endpoint = "oss-cn-beijing.aliyuncs.com";
    //accessKeyId和accessKeySecret是OSS的访问密钥
    private static String accessKeyId = "";
    private static String accessKeySecret = "";
    //Bucket用来管理所存储Object的存储空间
    private static String bucketName = "";
    //目标文件
    private static String objectName = "upload/123.txt";
    /**
     * 上传文件到阿里云OSS
     * @return
     */
    @PostMapping("/upload")
    @ResponseBody
    public String upload(MultipartFile file) throws IOException {
        //验证文件是否为空
        if(ObjectUtils.isEmpty(file) || file.getSize() <=0){
            return "file is empty";
        }
        InputStream inputStream = file.getInputStream();
        // 创建OSSClient实例
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);
        try {
            // 创建PutObjectRequest对象
            PutObjectRequest putObjectRequest = new PutObjectRequest(bucketName, objectName, inputStream);
            // 设置该属性可以返回response。如果不设置，则返回的response为空
            putObjectRequest.setProcess("true");
            // 创建PutObject请求
            PutObjectResult result = ossClient.putObject(putObjectRequest);
            // 如果上传成功，则返回200
            System.out.println(result.getResponse().getStatusCode());
        } catch (Exception e) {
            System.out.println("Error Message:" + e.getMessage());
        } 
        return "success";
    }

    /**
     * 下载阿里云文件到本地
     * @return
     */
    @PostMapping("/download")
    @ResponseBody
    public String download(String objName,String path) throws IOException {
        //下载目录
        String pathName = "download/123.txt";
        // 创建OSSClient实例
        OSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);
        try {
            // 下载Object到本地文件，并保存到指定的本地路径中
            ossClient.getObject(new GetObjectRequest(bucketName, objectName), new File(pathName));
        } catch (Exception e) {
            System.out.println("Error Message:" + e.getMessage());
        }
        return "success";
    }
}

7. Postman执行上传文件到本地目录

​

8. Postman执行上传到阿里云OSS

9. Postman执行从阿里云OSS下载文件到本地