图片Url转MultipartFile形式

1 前言

常常遇见这样一种情景：接受到了 URL 形式的图片，需要保存到自己的服务器上，这时候就需要使用 URL 转 MultipartFile 的功能，此文介绍转换的工具类。

2 图片

我准备转换的图片如下：

URL：http://bpic.588ku.com/element_origin_min_pic/19/03/15/75076c485081d15ed9c224ad3e4ce4a1.jpg

3 代码

import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.commons.CommonsMultipartFile;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileItemFactory;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.http.entity.ContentType;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;

public class Url2MultipartFile {
    public static void main(String[] args) throws IOException {
        String url = "http://bpic.588ku.com/element_origin_min_pic/19/03/15/75076c485081d15ed9c224ad3e4ce4a1.jpg";
        MultipartFile fileItem = createFileItem(url);
        File folder = new File("D:/data/pic");
        folder.mkdirs();
        fileItem.transferTo(new File(folder + "/pic.jpg"));
    }

    private static MultipartFile createFileItem(String url) {

        FileItem item = null;
        try {
            HttpURLConnection conn = (HttpURLConnection) new URL(url).openConnection();
            conn.setReadTimeout(30000);
            conn.setConnectTimeout(30000);
            //设置应用程序要从网络连接读取数据
            conn.setDoInput(true);
            conn.setRequestMethod("GET");
            if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {
                InputStream is = conn.getInputStream();
                // 创建工厂对象
                FileItemFactory factory = new DiskFileItemFactory(16, null);
                // 通过工厂对象创建 item 对象
                item = factory.createItem(null, ContentType.IMAGE_JPEG.toString(), false, null);
                OutputStream os = item.getOutputStream();
                int bytesRead = 0;
                byte[] buffer = new byte[8192];
                while ((bytesRead = is.read(buffer, 0, 8192)) != -1) {
                    os.write(buffer, 0, bytesRead);
                }
                os.close();
                is.close();
            }
        } catch (IOException e) {
            throw new RuntimeException("文件下载失败", e);
        }

        return new CommonsMultipartFile(item);
    }
}