Spring Boot 上傳/下載檔案 (上)

大家安安，今天來實作小畫家後端功能
1.上傳圖片 <-今天會介紹的
2.下載圖片
3.列出圖片網址

先設定application.properties的設定

# 允許多檔案上傳
spring.servlet.multipart.enabled=true
# Threshold after which files are written to disk.
spring.servlet.multipart.file-size-threshold=2KB
# 檔案最大大小
spring.servlet.multipart.max-file-size=200MB
# Max Request Size
spring.servlet.multipart.max-request-size=215MB

1.設計資料庫，處理entity
上傳圖片API，在資料庫應該要有幾個欄位
1.1資料格式，是jpg,txt之類的，之後若要分開列出比較方便
1.2ID
1.3檔案名稱
1.4使用者名稱
1.5檔案位置(要存取相對位置，這樣取出才方便)

@Repository
@Entity
@Table(name = "file_machan")
public class FileUpDownModel {

//    public FileUpDownModel(Integer id, Integer userId, String userName, String fileName, String type, String typeFormat, String fileDirectory) {
//        this.id = id;
//        this.userId = userId;
//        this.userName = userName;
//        this.fileName = fileName;
//        this.type = type;
//        this.filesize = typeFormat;
//        this.fileDirectory = fileDirectory;
//    }

    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    @Column(name = "id")
    private Integer id;


    public FileUpDownModel(){

    }


    public String getImgurl() {
        return imgurl;
    }

    public void setImgurl(String imgurl) {
        this.imgurl = imgurl;
    }

    @Column(name = "imgurl")
    private String  imgurl;

    @Column(name = "username")
    private String  userName;

    @Column(name = "filename")
    private String fileName;

    @Column(name = "type")
    private String type;

    public String getFilesize() {
        return filesize;
    }

    public void setFilesize(String filesize) {
        this.filesize = filesize;
    }

    @Column(name = "filesize")
    private String filesize;

    @Column(name = "filedirectory")
    private String fileDirectory="";


    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }


    public String getUserName() {
        return userName;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getFileName() {
        return fileName;
    }

    public void setFileName(String fileName) {
        this.fileName = fileName;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }


    public String getFileDirectory() {
        return fileDirectory;
    }

    public void setFileDirectory(String fileDirectory) {
        this.fileDirectory = fileDirectory;
    }

}

2.Repository
一樣，列出fileDirectory跟找全部

@Repository
public interface UpLoadRepository extends JpaRepository<FileUpDownModel,Integer> {
    FileUpDownModel findByFileDirectory (String fileDir);


    List<FileUpDownModel> findAll();
}

3.Service
先用依賴注入注入@Autowired repository
宣告一個path代表他要存在哪

@Service
public class
FileUpLoadService {

    @Autowired
    UpLoadRepository upLoadRepository;

    private Path fileStoreLocation;..}

3.1 constructor

@Autowired
public FileUpLoadService (FileUpDownModel upLoadModel){
      
    this.fileStoreLocation = Paths.get("/home/uuko/web/web-socket-project/src/main/resources/static/").toAbsolutePath().normalize();
    try {
        Files.createDirectories(this.fileStoreLocation);
    } catch (IOException e) {
        try {
            throw new Exception("Could not create the directory where the uploaded files will be stored",e);
        } catch (Exception exception) {
            exception.printStackTrace();
        }
    }
}

3.2

  public String storeNewFile(MultipartFile multipartFile,String userName,String fileSize) throws Exception {..}

拿到原本的fileName

String orgFileName = StringUtils.cleanPath(multipartFile.getOriginalFilename());

String newFileName = "";

判斷如果原本的fileName中有不符合元素
丟出exception
if (orgFileName.contains("..")){
throw new Exception("有不合法的元素 " + orgFileName);
}

拿ip
String command = "powershell -c "$(ipconfig | where {$_ -match 'IPv4.+\s(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})' } | out-null; $Matches[1]) > C:\Users\uuko\Desktop\web\web-socket-project\src\main\resources\ip.txt";

  String fileExtension="";
            String fileOrgName="";
            fileExtension=orgFileName.substring(orgFileName.lastIndexOf("."));
            fileOrgName=orgFileName.substring(0,orgFileName.lastIndexOf("."));
            newFileName=userName+"_"+fileOrgName+fileExtension;

接下來拿目標儲存地址，並複製到位置

     Path targetLocation = this.fileStoreLocation.resolve(newFileName);
            Files.copy(multipartFile.getInputStream(),targetLocation, StandardCopyOption.REPLACE_EXISTING);
            FileUpDownModel checkIfRepeat=upLoadRepository.findByFileDirectory(newFileName);

然後找到directory，看有沒有這個directory，然後把它存入資料庫

 if (checkIfRepeat!=null){
                checkIfRepeat.setImgurl("http://"+line0+":8080/"+newFileName);
                checkIfRepeat.setUserName(userName);
                checkIfRepeat.setFileName(newFileName);
                checkIfRepeat.setType(multipartFile.getContentType());
                checkIfRepeat.setFilesize(fileSize);
                checkIfRepeat.setFileDirectory(fileStoreLocation+"\\"+newFileName);
                upLoadRepository.save(checkIfRepeat);
            }

else {
                FileUpDownModel newFileModel = new FileUpDownModel();
                newFileModel.setImgurl("http://"+line0+":8080/"+newFileName);
                newFileModel.setType(multipartFile.getContentType());
                newFileModel.setFilesize(fileSize);
                newFileModel.setFileName(newFileName);
                newFileModel.setUserName(userName);
                newFileModel.setFileDirectory(fileStoreLocation+"\\"+newFileName);
                upLoadRepository.save(newFileModel);
            }
            return newFileName;

4.Controller
上傳

    @PostMapping("/uploadFile")
    public UploadFileResponse uploadFile(@RequestParam("file")MultipartFile file
    , @RequestParam("userName") String userName) throws Exception {



        String fileName=fileUpLoadService.storeNewFile(file,userName,String.valueOf(file.getSize()));


      ...

然後用servlet創出url並塞入資料庫

        String fileDownLoadUrL = ServletUriComponentsBuilder.fromCurrentContextPath()
        .path("/downloadFile/")
        .path(fileName)
        .toUriString();

**重點，要讓外面的人可以拿到圖片
就需要讓圖片是存在static資料夾才能拿到