前言

在日常开发中，常常会将文件服务交由一个服务管理，那么有时候就涉及到其他系统中会有文件上传接口的文件，要转发到公用文件服务接口的需求。正好项目中用到了，这里存下代码。

方法

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.MultipartEntityBuilder;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.springframework.web.multipart.MultipartFile;

import java.io.IOException;
import java.nio.charset.Charset;

/**
 * @Description
 * @Author ChengQichuan
 * @Version V1.0.0
 * @Since 1.0
 * @Date 2020/6/19
 */
public class HttpClientUtil {


    /**
     * 文件上传转发
     * @param url
     * @param file
     * @return
     */
    public static String httpClientUploadFile(String url, MultipartFile file) {
//        String remote_url = url;// 第三方服务器请求地址
        CloseableHttpClient httpClient = HttpClients.createDefault();
        String result = "";
        try {
            String fileName = file.getOriginalFilename();
            HttpPost httpPost = new HttpPost(url);
            MultipartEntityBuilder builder = MultipartEntityBuilder.create();
            builder.addBinaryBody("file", file.getInputStream(), ContentType.MULTIPART_FORM_DATA, fileName);// 文件流
            builder.addTextBody("type", "2");// 类似浏览器表单提交，对应input的name和value
            HttpEntity entity = builder.build();
            httpPost.setEntity(entity);
            HttpResponse response = httpClient.execute(httpPost);// 执行提交
            HttpEntity responseEntity = response.getEntity();
            if (responseEntity != null) {
                // 将响应内容转换为字符串
                result = EntityUtils.toString(responseEntity, Charset.forName("UTF-8"));
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

}