java调用接口实现文件上传

import com.gap.open.core.base.IOpenApi;
import com.gap.open.core.base.OpenAuthConfig;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.collections.map.HashedMap;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.multipart.MultipartFile;
import org.springframework.web.multipart.MultipartHttpServletRequest;

import javax.annotation.Resource;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;
import java.util.UUID;

/**
 * @author huqi 2021/8/12
 */
@Slf4j
@Configuration
public class UploadFile {

    @Resource
    private OpenAuthConfig openAuthConfig;

    public File transferToFile(MultipartFile multipartFile) {
        // 选择用缓冲区来实现这个转换即使用java 创建的临时文件 使用 MultipartFile.transferto()方法 。
        File file = null;
        try {
            String filename = multipartFile.getResource().getFilename();
            String suffix = filename.substring(filename.lastIndexOf("."));
            file=File.createTempFile(UUID.randomUUID().toString(), suffix);
            multipartFile.transferTo(file);
            file.deleteOnExit();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return file;
    }

    public String upLoadFilePost(String actionUrl, MultipartHttpServletRequest request, String token) throws IOException {
        Map<String, MultipartFile> fileTemp = request.getFileMap();
        Map<String, File> files = new HashedMap();
        for(String key : fileTemp.keySet()){
            files.put(key,transferToFile(fileTemp.get(key)));
        }
        actionUrl = openAuthConfig.getDomainName() + actionUrl;
        log.info("post地址"+actionUrl);
        String BOUNDARY = java.util.UUID.randomUUID().toString();
        String PREFIX = "--", LINEND = "\r\n";
        String MULTIPART_FROM_DATA = "multipart/form-data";
        String CHARSET = "UTF-8";
        URL uri = new URL(actionUrl);
        HttpURLConnection conn = (HttpURLConnection) uri.openConnection();
        conn.setReadTimeout(5 * 1000);
        conn.setDoInput(true);
        conn.setDoOutput(true);
        conn.setUseCaches(false);
        conn.setRequestMethod("POST");
        conn.setRequestProperty("connection", "keep-alive");
        conn.setRequestProperty("Charsert", "UTF-8");
        conn.setRequestProperty("Content-Type", MULTIPART_FROM_DATA
                + ";boundary=" + BOUNDARY);
        conn.setRequestProperty(IOpenApi.BASIC_HEADER_TOKEN, IOpenApi.TOKEN_BEARER + token);
        DataOutputStream outStream = new DataOutputStream(
                conn.getOutputStream());
        // 发送文件数据
        if (files != null) {
            for (Map.Entry<String, File> file : files.entrySet()) {
                StringBuilder sb1 = new StringBuilder();
                sb1.append(PREFIX);
                sb1.append(BOUNDARY);
                sb1.append(LINEND);
                sb1.append("Content-Disposition: form-data; name=\"file\"; filename=\""
                        + file.getValue().getName() + "\"" + LINEND);
                sb1.append("Content-Type: application/octet-stream; charset="
                        + CHARSET + LINEND);
                sb1.append(LINEND);
                outStream.write(sb1.toString().getBytes());
                InputStream is = new FileInputStream(file.getValue());
                byte[] buffer = new byte[1024];
                int len = 0;
                while ((len = is.read(buffer)) != -1) {
                    outStream.write(buffer, 0, len);
                }
                is.close();
                outStream.write(LINEND.getBytes());
            }
        }
        // 请求结束标志
        byte[] end_data = (PREFIX + BOUNDARY + PREFIX + LINEND).getBytes();
        outStream.write(end_data);
        outStream.flush();
        // 得到响应码
        int res = conn.getResponseCode();
        if (res == 200) {
            InputStream in = conn.getInputStream();
            InputStreamReader isReader = new InputStreamReader(in);
            BufferedReader bufReader = new BufferedReader(isReader);
            String line = "";
            String data = "";
            while ((line = bufReader.readLine()) != null) {
                data += line;
            }
            outStream.close();
            conn.disconnect();
            return data;
        }
        outStream.close();
        conn.disconnect();
        return null;
    }
}