如何将图片/文件的base64字符串转换为FilePart

import org.springframework.core.io.ByteArrayResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.client.MultipartBodyBuilder;
import org.springframework.http.codec.multipart.FilePart;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Base64;

public class Base64ToFilePartConverter {
    public static FilePart convert(String base64String) throws IOException {
        // 解码base64字符串为字节数组
        byte[] bytes = Base64.getDecoder().decode(base64String);

        // 将字节数组写入文件
        File file = new File("temp.jpg");
        try (FileOutputStream fos = new FileOutputStream(file)) {
            fos.write(bytes);
        }

        // 创建FilePart对象
        MultipartBodyBuilder builder = new MultipartBodyBuilder();
        builder.part("file", new ByteArrayResource(bytes) {
            @Override
            public String getFilename() {
                return "temp.jpg";
            }
        }, MediaType.IMAGE_JPEG);

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.MULTIPART_FORM_DATA);

        return new FilePart("file", file, headers);
    }
}