Upload Image File as Base64 String in Spring Boot

To upload image files as a String in Spring Boot, the file must first be converted into a Base64 string on the frontend and transfer the resulting value via a REST api. It is also imported to note that the size of the encoded Base64 file is increased by 33% of the original size. Therefore, this method is generally not preferred by most of the developers.

Follow these steps:

  1. Create a DTO class with two fields as shown in the example below:
    public class ImageDTO {
    	private String fileContentBase64;
    	private String fileName;
    	public String getFileContentBase64() {
    		return fileContentBase64;
    	public void setFileContentBase64(String fileContentBase64) {
    		this.fileContentBase64 = fileContentBase64;
    	public String getFileName() {
    		return fileName;
    	public void setFileName(String fileName) {
    		this.fileName = fileName;

    If you're going to save the file as a string in a database then you should also save the filename because you'll need it later to convert the base64 value to a file.

  3. Create a controller to upload an image file as a string:
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RequestBody;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    import com.example.uploadfiles.dto.ImageDTO;
    @RequestMapping(path = "/upload")
    public class ImageUploadController {
    	@PostMapping(path = "/images")
    	public void uploadFile(@RequestBody  ImageDTO imageDTO) {
    		// Here you can save image base64 string to database