SpringBoot文件上传-编程知识

前端

<form action="/upload" method="post" enctype="multipart/form-data">姓名: <input type="text" name="username"><br>年龄: <input type="text" name="age"><br>头像: <input type="file" name="image"><br><input type="submit" value="提交">
</form>

三要素：

method 为post，因为post适合上传大文件
enctype=“multipart/form-data”
type=“file”

后端

Springboot默认单个文件最大为1M，可以在配置文件中进行设置

spring:#文件上传的配置servlet:multipart:max-file-size: 10MB # 单个文件max-request-size: 100MB #多个文件总大小

本地存储

@PostMapping("/upload")
public Result upload(String username , Integer age , MultipartFile image) throws Exception {log.info("文件上传: {}, {}, {}", username, age, image);//获取原始文件名String originalFilename = image.getOriginalFilename();//构造唯一的文件名 (不能重复) - uuid(通用唯一识别码)int index = originalFilename.lastIndexOf(".");//获取文件的后缀名String extname = originalFilename.substring(index);String newFileName = UUID.randomUUID() + extname;log.info("新的文件名: {}", newFileName);//将文件存储在服务器的磁盘目录中String path = "D:\\upload"+newFileName;image.transferTo(new File(path));return Result.success();
}

阿里云OSS存储

https://oss.console.aliyun.com/bucket
创建一个bucket

点击右上角AccessKey管理，添加一个Key

查看SDK帮助文档：
https://oss.console.aliyun.com/sdk
以及OSS文档
https://help.aliyun.com/zh/oss/developer-reference/overview-21

使用

引入maven依赖

<dependency><groupId>com.aliyun.oss</groupId><artifactId>aliyun-sdk-oss</artifactId><version>3.15.1</version>
</dependency>

java9以上需要添加下面依赖

<dependency><groupId>javax.xml.bind</groupId><artifactId>jaxb-api</artifactId><version>2.3.1</version>
</dependency>
<dependency><groupId>javax.activation</groupId><artifactId>activation</artifactId><version>1.1.1</version>
</dependency>
<!-- no more than 2.3.3-->
<dependency><groupId>org.glassfish.jaxb</groupId><artifactId>jaxb-runtime</artifactId><version>2.3.3</version>
</dependency>

复制阿里云提供的示例代码

import com.aliyun.oss.ClientException;
import com.aliyun.oss.OSS;
import com.aliyun.oss.common.auth.*;
import com.aliyun.oss.OSSClientBuilder;
import com.aliyun.oss.OSSException;
import com.aliyun.oss.model.PutObjectRequest;
import com.aliyun.oss.model.PutObjectResult;
import java.io.File;public class Demo {public static void main(String[] args) throws Exception {// Endpoint以华东1（杭州）为例，其它Region请按实际情况填写。String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";// 从环境变量中获取访问凭证。运行本代码示例之前，请确保已设置环境变量OSS_ACCESS_KEY_ID和OSS_ACCESS_KEY_SECRET。EnvironmentVariableCredentialsProvider credentialsProvider = CredentialsProviderFactory.newEnvironmentVariableCredentialsProvider();// 填写Bucket名称，例如examplebucket。String bucketName = "examplebucket";// 填写Object完整路径，完整路径中不能包含Bucket名称，例如exampledir/exampleobject.txt。String objectName = "exampledir/exampleobject.txt";// 填写本地文件的完整路径，例如D:\\localpath\\examplefile.txt。// 如果未指定本地路径，则默认从示例程序所属项目对应本地路径中上传文件。String filePath= "D:\\localpath\\examplefile.txt";// 创建OSSClient实例。OSS ossClient = new OSSClientBuilder().build(endpoint, credentialsProvider);try {// 创建PutObjectRequest对象。PutObjectRequest putObjectRequest = new PutObjectRequest(bucketName, objectName, new File(filePath));// 如果需要上传时设置存储类型和访问权限，请参考以下示例代码。// ObjectMetadata metadata = new ObjectMetadata();// metadata.setHeader(OSSHeaders.OSS_STORAGE_CLASS, StorageClass.Standard.toString());// metadata.setObjectAcl(CannedAccessControlList.Private);// putObjectRequest.setMetadata(metadata);// 上传文件。PutObjectResult result = ossClient.putObject(putObjectRequest);           } catch (OSSException oe) {System.out.println("Caught an OSSException, which means your request made it to OSS, "+ "but was rejected with an error response for some reason.");System.out.println("Error Message:" + oe.getErrorMessage());System.out.println("Error Code:" + oe.getErrorCode());System.out.println("Request ID:" + oe.getRequestId());System.out.println("Host ID:" + oe.getHostId());} catch (ClientException ce) {System.out.println("Caught an ClientException, which means the client encountered "+ "a serious internal problem while trying to communicate with OSS, "+ "such as not being able to access the network.");System.out.println("Error Message:" + ce.getMessage());} finally {if (ossClient != null) {ossClient.shutdown();}}}
}

编辑.bash_profile文件

export OSS_ACCESS_KEY_ID= 
export OSS_ACCESS_KEY_SECRET=

上面这种是为了演示Demo做的，在项目中是写在yml文件里面，可以定义下面属性：

#阿里云OSS
aliyun:oss:endpoint: xxxaccessKeyId: xxxaccessKeySecret: xxxbucketName: xxx

通过文件读取：

@Data
@Component
@ConfigurationProperties(prefix = "aliyun.oss")
public class AliOSSProperties {private String endpoint;private String accessKeyId;private String accessKeySecret;private String bucketName;
}

上传图片工具类：


/*** 阿里云 OSS 工具类*/
@Component
public class AliOSSUtils {@Autowiredprivate AliOSSProperties aliOSSProperties;/*** 实现上传图片到OSS*/public String upload(MultipartFile file) throws IOException {//获取阿里云OSS参数String endpoint = aliOSSProperties.getEndpoint();String accessKeyId = aliOSSProperties.getAccessKeyId();String accessKeySecret = aliOSSProperties.getAccessKeySecret();String bucketName = aliOSSProperties.getBucketName();// 获取上传的文件的输入流InputStream inputStream = file.getInputStream();// 避免文件覆盖String originalFilename = file.getOriginalFilename();String fileName = UUID.randomUUID().toString() + originalFilename.substring(originalFilename.lastIndexOf("."));//上传文件到 OSSOSS ossClient = new OSSClientBuilder().build(endpoint, accessKeyId, accessKeySecret);ossClient.putObject(bucketName, fileName, inputStream);//文件访问路径String url = endpoint.split("//")[0] + "//" + bucketName + "." + endpoint.split("//")[1] + "/" + fileName;// 关闭ossClientossClient.shutdown();return url;// 把上传到oss的路径返回}
}

Controller中使用：

@Autowired
private AliOSSUtils aliOSSUtils;@PostMapping("/upload")
public Result upload(MultipartFile image) throws IOException {log.info("文件上传, 文件名: {}", image.getOriginalFilename());//调用阿里云OSS工具类进行文件上传String url = aliOSSUtils.upload(image);log.info("文件上传完成,文件访问的url: {}", url);return Result.success(url);
}