multipart/form-data格式接口调用工具类，实现文件上传

1、添加依赖

    <dependencies>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
        </dependency>
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
        </dependency>
    </dependencies>

2、举例工具类（具体请求参数自调）

package com.xpf.utils;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.mime.HttpMultipartMode;
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 java.io.IOException;
import java.io.InputStream;
import java.net.URISyntaxException;
import java.nio.charset.Charset;
import java.util.HashMap;

public class MulFormDataUtils {


    /**
     * multipart/form-data格式接口调用
     * @param headMap 请求头（自行根据调用接口封装）
     * @param url
     * @param paramMap 请求参数（自行根据调用接口封装）
     * @param inputStream
     * @return
     */
    public static String doPostUploadFile(HashMap<String, Object> headMap, String url, HashMap<String, Object> paramMap, InputStream inputStream){

        CloseableHttpClient client = HttpClients.createDefault();
        HttpPost post = new HttpPost();

        try {
            URIBuilder urlBuilder = new URIBuilder(url);
            post.setURL(urlBuilder.build());
        } catch (URISyntaxException e) {
            e.printStackTrace();
        }
        
        //封装请求头head
        //（ 千万千万不要把 "Content-Type":"multipart/form-data" 封装进请求头，否则会请求出错 ）
        //以下举例三条，根据需要调的接口的实际情况封装
        //headMap.put("x-qys-accesstoken", accessToken);
        //headMap.put("x-qys-timestamp", String.valueOf(timestamp));
        //headMap.put("x-qys-signature", md5Str);
        headMap.entrySet().forEach(p -> post.setHeader(p.getKey(), String.valueOf(p.getValue()) ));

        //解决中文乱码问题
        MultipartEntityBuilder builder = MultipartEntityBuilder.create();
        builder.setCharset(Charset.forName("UTF-8"));
        builder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
        builder.addBinaryBody("file", inputStream, ContentType.DEFAULT_BINARY.withCharset("UTF-8"), String.valueOf(paramMap.get("title")));

        //(这个是要调的接口的参数，根据实际情况组装)解决文件名中文乱码（？？？）
        builder.addTextBody("title", String.valueOf(paramMap.get("title")), ContentType.DEFAULT_TEXT.withCharset("UTF-8"));
        builder.addTextBody("fileType", String.valueOf(paramMap.get("fileType")));

        HttpEntity entity = builder.build();
        post.setEntity(entity);
        String result = null;

        try {
            HttpResponse response = client.execute(post);
            result = EntityUtils.toString(response.getEntity(), "UTF-8");

        } catch (IOException e) {
            e.printStackTrace();
        }

        return result;
    }


}

扩展一：

1、上面工具类一般是用于我方图片传到对方服务器上，需要封装请求头的情况。

下面假设对方系统一般会给你一个图片url，需要上传到我服务器上。

//文件上传（不需要封装请求头的）
/*
 * url：上传到我方需要调用的接口url
 * fileName：文件名
 * inputStream：需要上传的图片资源流
 *
*/
    public static String doPost(String url, String fileName, InputStream inputStream) {
        CloseableHttpClient httpClient = HttpClients.createDefault();
        String result = "";
        try {
            HttpPost httpPost = new HttpPost(url);
            MultipartEntityBuilder builder = MultipartEntityBuilder.create().setMode(HttpMultipartMode.RFC6532);
            // 文件流
            builder.addBinaryBody("files", inputStream, ContentType.MULTIPART_FORM_DATA, fileName);
            HttpEntity entity = builder.build();
            httpPost.setEntity(entity);
            // 执行提交
            HttpResponse response = httpClient.execute(httpPost);
            HttpEntity responseEntity = response.getEntity();
            if (responseEntity != null) {
                // 将响应内容转换为字符串
                result = EntityUtils.toString(responseEntity, StandardCharsets.UTF_8);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                httpClient.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }

2、实际调用仅供参考（对方一般会提供一个图片资源url，将url转成inputStream，再调用1中的接口即可）

//示例：提供一个图片url上传到远端服务器
List<Map<String, Object>> file0InfoList = getApplicationFormFileInfo(0, ytenantId);
for (int i = 0; i < file0InfoList.size(); i++) {
Map<String, Object> file0Map = file0InfoList.get(i);
//中间表id
String id = String.valueOf(file0Map.get("id"));
String applicationFormNo = String.valueOf(file0Map.get("application_form_no"));
String fileType = String.valueOf(file0Map.get("file_type"));
String fileUrl = String.valueOf(file0Map.get("file_url"));
String fileName = String.valueOf(file0Map.get("file_name"));
//需要上传图片资源的单据id
String formId = getReplaceApplicationFormId(fileType, applicationFormNo, ytenantId);

String suffix = null;
if (fileUrl.contains("jpeg")) {
	suffix = ".jpeg";
} else if (fileUrl.contains("jpg")) {
	suffix = ".jpg";
} else if (fileUrl.contains("png")) {
	suffix = ".png";
} else if (fileUrl.contains("JPEG")) {
	suffix = ".jpeg";
} else if (fileUrl.contains("JPG")) {
	suffix = ".jpg";
} else if (fileUrl.contains("PNG")) {
	suffix = ".png";
}
//（fileUrl是对方提供的需要上传的图片url）
URL url = new URL(UriUtils.encodePath(fileUrl, StandardCharsets.UTF_8));
//建立链接 获取流
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestProperty("Content-Type", "plain/text;charset=" + StandardCharsets.UTF_8);
conn.setRequestProperty("charset", String.valueOf(StandardCharsets.UTF_8));
conn.setDoInput(true);
conn.setDoOutput(true);
inStream = conn.getInputStream();
//（saveFileUrl是我方服务器url）
String saveFileUrl = appConfig.getDomainUrl() + FILEURL + accessToken + "&businessType=" + BUSINESSTYPE + "&businessId=" + formId;
//（调用1中的doPost()方法）
String doPost = doPost(saveFileUrl, fileName + suffix, inStream);
if (StringUtils.isNotBlank(doPost)) {
	JSONObject result = JSONObject.parseObject(doPost);
	if ("200".equals(result.get("code"))) {
		//上传完图片到BIP获取到返回的图片id
		String fileId = ((Map<String, String>) (((JSONArray) (((JSONObject) result.get("data")).get("data"))).get(0))).get("id");
		//更新version = 1 和 file_id
		if (StringUtils.isNotBlank(fileId)) {
			ApplicationFormFile applicationFormFile = new ApplicationFormFile();
			applicationFormFile.setId(id);
			applicationFormFile.setFileId(fileId);
			applicationFormFile.setVersion(1);
			applicationFormFile.setModifyTime(DateUtil.getNow());
			applicationFormFile.setPubts(DateUtil.getNow());

			int opr = applicationFormFileMapper.updateByPrimaryKeySelective(applicationFormFile);
		}

	} else {
		log.error("附件保存异常: {}。请确认图片url资源可以访问：{}", doPost, fileUrl);
	}

}

扩展二：获取不同接口的返回结果

1、获取接口返回的输入流（仅供参考）

//获取接口返回的输入流
try {
	HttpResponse response = com.yonyou.iuap.utils.HttpUtil.getInstance().doPost(domain + url,null,paramMap,headMap);
	InputStream inputStream = null;
	if (response != null) {
		int status = response.getStatusLine().getStatusCode();
		if (status >= 200 && status < 300) {
			HttpEntity resEntity = response.getEntity();
			if (resEntity != null) {
				inputStream = resEntity.getContent();
			}
		}
		return inputStream;
	}
} catch (Exception e) {
	log.info(ResultMessage.error(e.getMessage()));
}

2、获取接口返回的string类型数据（仅供参考）

//获取接口返回的string类型数据
HttpResponse response = HttpUtil.getInstance().doPost(delFileUrl, null, null);
if (response != null) {
    int status = response.getStatusLine().getStatusCode();
    if (status >= 200 && status < 300) {
        HttpEntity resEntity = response.getEntity();
        if (resEntity != null) {
            String result = EntityUtils.toString(resEntity);
            JSONObject jsonObject = JSONObject.parseObject(result);
            if ("200".equals(jsonObject.get("code"))) {
                //更新version = 0
                ApplicationFormFile applicationFormFile = new ApplicationFormFile();
                applicationFormFile.setId(id);
                applicationFormFile.setVersion(0);
                applicationFormFile.setModifyTime(DateUtil.getNow());
                applicationFormFile.setPubts(DateUtil.getNow());
                applicationFormFileMapper.updateByPrimaryKeySelective(applicationFormFile);
            }
        }

    }
}